研究者総覧
宮林 謙吉 (ミヤバヤシ ケンキチ)
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Last Updated :2021/06/02
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学位
研究キーワード
- 無機シンチレーター結晶を用いた電磁カロリメーターの開発研究 クオーコニウム似エキゾチックハドロンの探索 Ｂ中間子崩壊過程におけるＣＰ非保存測定 電子・陽電子衝突による素粒子の実験的研究 development of the electromagnetic calorimeter with in-organic scintillators. Search for Quarkonium-like exotic hadrons Measurements of CP violation in B meson decay Experimental study of elementary particles with electron-positron collider
研究分野
経歴
- 2007年04月 - 2012年03月 奈良女子大学 理学部 准教授
- 2016年04月 奈良女子大学 研究院 自然科学系 教授
- 1998年04月 - 2007年03月 奈良女子大学 理学部 助教授
- 1994年10月 - 1998年03月 奈良女子大学 理学部 助手
- 2012年04月 - 2016年03月 奈良女子大学 研究院 自然科学系 准教授
学歴
- - 1994年09月 名古屋大学 大学院理学研究科 博士後期課程物理学専攻 中退 日本国
- - 1992年03月 名古屋大学 大学院理学研究科 博士前期課程物理学専攻 修了
- - 1990年03月 名古屋大学 理学部 物理学科 卒業 日本国
委員歴
- 2004年05月 - 2005年04月 日本物理学会 素粒子実験領域世話人 日本物理学会 society
学協会
- 2013年02月 大阪大学核物理研究センター 高運動量ビームラインにおけるハドロン分光計画・技術諮問委員会
- 2020年04月 - 2022年03月 大阪大学核物理研究センター 大阪大学核物理研究センター運営委員会委員 others
その他
論文
Study of B →p p ππ STUDY of B →p p ππ CHU K. et al.
© 2020 authors. Using a data sample of 772×106 BB pairs collected on the Ï'(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e-collider, we report the observation of B0→ppπ+π- A nd the first observation of B+→ppπ+π0. We measure a decay branching fraction of (0.83±0.17±0.17)×10-6 in B0→ppπ+π-for Mπ+π-<1.22 GeV/c2 with a significance of 5.5 standard deviations. The contribution from B0→ppK0 is excluded. We measure a decay branching fraction of (4.58±1.17±0.67)×10-6 for B+→ppπ+π0 with Mπ+π0<1.3 GeV/c2 with a significance of 5.4 standard deviations. We study the difference of the Mpp distributions in B0→ppπ+π- A nd B+→ppπ+π0., 2020年03月01日, Physical Review D, 101 (5), doi;scopus;scopus_citedby研究論文（学術雑誌）
Observation of a vector charmoniumlike state in e+e-→ Ds+ Ds1 (2536)-+ c. c.
© 2019 authors. Published by the American Physical Society. Using a data sample of 921.9 fb-1 collected with the Belle detector, we study the process of e+e-→Ds+Ds1(2536)-+c.c. via initial-state radiation. We report the first observation of a vector charmoniumlike state decaying to Ds+Ds1(2536)-+c.c. with a significance of 5.9σ, including systematic uncertainties. The measured mass and width are (4625.9-6.0+6.2(stat)±0.4(syst)) MeV/c2 and (49.8-11.5+13.9(stat)±4.0(syst)) MeV, respectively. The product of the e+e-→Ds+Ds1(2536)-+c.c. cross section and the branching fraction of Ds1(2536)-→D∗0K-is measured from the DsDs1(2536) threshold to 5.59 GeV., 2019年12月31日, Physical Review D, 100 (11), doi;scopus;scopus_citedby研究論文（学術雑誌）
Search for the rare decay of B+ →+νγ with improved hadronic tagging
© 2018 authors. Published by the American Physical Society. We present the result of the search for the rare B meson decay of B+→+νγ with =e,μ. For the search the full data set recorded by the Belle experiment of 711 fb-1 integrated luminosity near the (4S) resonance is used. Signal candidates are reconstructed for photon energies Eγ larger than 1 GeV using a novel multivariate tagging algorithm. The novel algorithm fully reconstructs the second B meson produced in the collision using hadronic modes and was specifically trained to recognize the signal signature in combination with hadronic tag-side B meson decays. This approach greatly enhances the performance. Background processes that can mimic this signature, mainly charmless semileptonic decays and continuum processes, are suppressed using multivariate methods. The number of signal candidates is determined by analyzing the missing mass squared distribution as inferred from the signal side particles and the kinematic properties of the tag-side B meson. No significant excess over the background-only hypothesis is observed and upper limits on the partial branching fraction ΔB with Eγ>1 GeV individually for electron and muon final states as well as for the average branching fraction of both lepton final states are reported. We find a Bayesian upper limit of ΔB(B+→+νγ)<3.0×10-6 at 90% CL and also report an upper limit on the first inverse moment of the light-cone distribution amplitude of the B meson of λB>0.24 GeV at 90% CL., 2018年12月01日, Physical Review D, 98 (11), doi;url;scopus_citedby研究論文（学術雑誌）
Measurement of ηc (1S), ηc (2S), and nonresonant η′π+π- production via two-photon collisions
© 2018 authors. Published by the American Physical Society. We report the measurement of γγ→ηc(1S),ηc(2S)→η′π+π- with η′ decays to γρ and ηπ+π- using 941 fb-1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The ηc(1S) mass and width are measured to be M=[2984.6±0.7 (stat)±2.2 (syst)±0.3 (model)] MeV/c2 and Γ=[30.8-2.2+2.3 (stat)±2.5 (syst)±1.4 (model)] MeV, respectively. First observation of ηc(2S)→η′π+π- with a significance of 5.5σ including systematic error is obtained, and the ηc(2S) mass is measured to be M=[3635.1±3.7 (stat)±2.9 (syst)±0.4 (model)] MeV/c2. The products of the two-photon decay width and branching fraction (B) of decays to η′π+π- are determined to be ΓγγΓγγB=[65.4±2.6 (stat)±7.8 (syst)] eV for ηc(1S) and [5.6-1.1+1.2 (stat)±1.1 (syst)] eV for ηc(2S). The cross sections for γγ→η′π+π- and η′f2(1270) are measured for the first time., 2018年10月01日, Physical Review D, 98 (7), 1-19, doi;scopus;scopus_citedby研究論文（学術雑誌）
Observation of Π (4S) →η′ Π (1S)
© 2018 American Physical Society. Published by the American Physical Society under the terms of the «https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. We report the first observation of the hadronic transition Π(4S)→η′ Π (1S), using 496 fb-1 data collected at the Π (4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct the η′ meson through its decays to ρ0γ and to π+π-η, with η→γγ. We measure B(Π(4S)→η′Π(1S))=[3.43±0.88(stat)±0.21(syst)]×10-5, with a significance of 5.7σ., 2018年08月06日, Physical Review Letters, 121 (6), doi;pubmed;scopus;scopus_citedby研究論文（学術雑誌）
Search for ϒ(1S,2S)→Zc+Zc(′)− and e+e−→Zc+Zc(′)− at s=10.52 , 10.58, and 10.867 GeV
© 2018 American Physical Society. The first search for double charged charmoniumlike state production in Ï?(1S) and Ï?(2S) decays and in e+e- annihilation at s=10.52, 10.58, and 10.867 GeV is conducted using data collected with the Belle detector at the KEKB asymmetric energy electron-positron collider. No significant signals are observed in any of the studied modes, and the 90% credibility level upper limits on their product branching fractions in Ï?(1S) and Ï?(2S) decays [B(Ï?(1S,2S)→Zc+Zc(′)-)×B(Zc+→π++cc) (cc=J/ψ, χc1(1P), ψ(2S))] and the product of Born cross section and branching fraction for e+e-→Zc+Zc(′)- (σ(e+e-→Zc+Zc(′)-)×B(Zc+→π++cc)) at s=10.52, 10.58, and 10.867 GeV are determined. Here, Zc refers to the Zc(3900) and Zc(4200) observed in the πJ/ψ final state, the Zc1(4050) and Zc2(4250) in the πχc1(1P) final state, and the Zc(4050) and Zc(4430) in the πψ(2S) final state., 2018年06月14日, Physical Review D, 97 (11), 1-16, doi;scopus;scopus_citedby研究論文（学術雑誌）
Study of KS0 pair production in single-tag two-photon collisions
© 2018 authors. We report a measurement of the cross section for KS0 pair production in single-tag two-photon collisions, γ∗γ→KS0KS0, for Q2 up to 30 GeV2, where Q2 is the negative of the invariant mass squared of the tagged photon. The measurement covers the kinematic range 1.0 GeV研究論文（学術雑誌）
Measurement of the τ Michel parameters η and ξκ in the radiative leptonic decay τ - → l - ν
© The Author(s) 2018. We present a measurement of the Michel parameters of the τ lepton, η and ξκ, in the radiative leptonic decay τ - → l - ν τ ν l γ using 711 fb -1 of collision data collected with the Belle detector at the KEKB e + e - collider. The Michel parameters are measured in an unbinned maximum likelihood fit to the kinematic distribution of e + e - → τ + τ - → (π + π 0 ν τ )(l - ν τ ν l γ)(l = e or μ The measured values of the Michel parameters are η = -1.3 ± 1.5 ± 0.8 and ξκ = 0.5 ± 0.4 ± 0.2, where the first error is statistical and the second is systematic. This is the first measurement of these parameters. These results are consistent with the Standard Model predictions within their uncertainties, and constrain the coupling constants of the generalized weak interaction., 2018年02月01日, Progress of Theoretical and Experimental Physics, 2018 (2), 1-26, doi;scopus;scopus_citedbyτ νl γ研究論文（学術雑誌）
Averages of b-hadron, c-hadron, and τ -lepton properties as of summer 2016
© 2017, The Author(s). This article reports world averages of measurements of b-hadron, c-hadron, and τ-lepton properties obtained by the Heavy Flavor Averaging Group using results available through summer 2016. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays, and Cabbibo–Kobayashi–Maskawa matrix elements., 2017年12月01日, European Physical Journal C, 77 (12), doi;scopus;scopus_citedby研究論文（学術雑誌）
Study of η and dipion transitions in ϒ(4S) decays to lower bottomonia
© 2017 American Physical Society. We study hadronic transitions between bottomonium states using 496 fb-1 data collected at the ?(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e-collider. We measure B(?(4S)→π+π(1S))=(8.2±0.5(stat)±0.4(syst))×10-5, B(?(4S)→π+π(2S))=(7.9±1.0(stat)±0.4(syst))×10-5, and B(?(4S)→η?(1S))=(1.70±0.23(stat)±0.08(syst))×10-4. We measure the ratio of branching fractions R=B(?(4S)→η?(1S))/B(?(4S)→π+π(1S))=2.07±0.30(stat)±0.11(syst). We search for the decay ?(1D31,2)→η?(1S), but do not find significant evidence for such a transition. We also measure the initial-state radiation production cross sections of the ?(2S,3S) resonances and we find values compatible with the expected ones. Finally, the analysis of the ?(4S)→π+π(1S) events shows indications for a resonant contribution due to the f0(980) meson., 2017年09月01日, Physical Review D, 96 (5), 1-11, doi;scopus;scopus_citedby研究論文（学術雑誌）
Search for the 0 - Glueball in (1S) and (2S) decays
© 2017 American Physical Society. We report the first search for the JPC=0 - glueball in (1S) and (2S) decays with data samples of (102±2)×106 and (158±4)×106 events, respectively, collected with the Belle detector. No significant signals are observed in any of the proposed production modes, and the 90% credibility level upper limits on their branching fractions in (1S) and (2S) decays are obtained. The inclusive branching fractions of the (1S) and (2S) decays into final states with a χc1 are measured to be B( (1S)→χc1+anything)=(1.90±0.43(stat)±0.14(syst))×10-4 with an improved precision over prior measurements and B((2S)→χc1+anything)=(2.24±0.44(stat)±0.20(syst))×10-4 for the first time., 2017年01月04日, Physical Review D, 95 (1), 1-13, doi;scopus;scopus_citedby研究論文（学術雑誌）
Studies of charmed strange baryons in the Λd final state at Belle
© 2016 American Physical Society. We report the discovery of Ξc(3055)0, observed by its decay into the final-state ΛD0, and present the first observation and evidence of the decays of Ξc(3055)+ and Ξc(3080)+ into ΛD+. We also perform a combined analysis of the ΛD+ with the Σc++K- and Σc∗++K- decay modes to measure the ratios of branching fractions, masses and widths with improved accuracy. We measure the ratios of branching fractions B(Ξc(3055)+→ΛD+)/B(Ξc(3055)+→Σc++K-)=5.09±1.01±0.76, B(Ξc(3080)+→ΛD+)/B(Ξc(3080)+→Σc++K-)=1.29±0.30±0.15, and B(Ξc(3080)+→Σc∗++K-)/B(Ξc(3080)+→Σc++K-)=1.07±0.27±0.04, where the uncertainties are statistical and systematic. The analysis is performed using a 980 fb-1 data sample collected with the Belle detector at the KEKB asymmetric-energy e+e- collider., 2016年08月08日, Physical Review D, 94 (3), 1-13, doi;scopus;scopus_citedby研究論文（学術雑誌）
Observation of the Decay Bs0 →k0 K 0
© 2016 American Physical Society. We measure the decay Bs0→K0K0 using data collected at the ?(5S) resonance with the Belle detector at the KEKB e+e- collider. The data sample used corresponds to an integrated luminosity of 121.4 fb-1. We measure a branching fraction B(Bs0→K0K0)=[19.6-5.1+5.8(stat)±1.0(syst)±2.0(NBs0Bs0)]×10-6 with a significance of 5.1 standard deviations. This measurement constitutes the first observation of this decay., 2016年04月, Physical Review Letters, 116 (16), 1-6, doi;scopus;scopus_citedby研究論文（学術雑誌）
Search for the rare decay D0 →γγ at Belle
© 2016 American Physical Society. We search for the rare radiative decay D0→γγ using a data sample with an integrated luminosity of 832 fb-1 recorded by the Belle detector at the KEKB e+e- asymmetric-energy collider. We find no statistically significant signal and set an upper limit on the branching fraction of B(D0→γγ)<8.5×10-7 at 90% confidence level. This is the most restrictive limit on the decay channel to date., 2016年03月09日, Physical Review D, 93 (5), 1-7, doi;scopus;scopus_citedby研究論文（学術雑誌）
Measurement of the decay B →dℓνℓ in fully reconstructed events and determination of the Cabibbo-Kobayashi-Maskawa matrix element |Vcb |
© 2016 American Physical Society. We present a determination of the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element |Vcb| using the decay B→Dℓνℓ (ℓ=e,μ) based on 711 fb-1 of e+e-→ (4S) data recorded by the Belle detector and containing 772×106 BB¯ pairs. One B meson in the event is fully reconstructed in a hadronic decay mode, while the other, on the signal side, is partially reconstructed from a charged lepton and either a D+ or D0 meson in a total of 23 hadronic decay modes. The isospin-averaged branching fraction of the decay B→Dℓνℓ is found to be B(B0→D-ℓ+νℓ)=(2.31±0.03(stat)±0.11(syst))%. Analyzing the differential decay rate as a function of the hadronic recoil with the parametrization of Caprini, Lellouch, and Neubert and using the form-factor prediction G(1)=1.0541±0.0083 calculated by FNAL/MILC, we obtain ηEW|Vcb|=(40.12±1.34)×10-3, where ηEW is the electroweak correction factor. Alternatively, assuming the model-independent form-factor parametrization of Boyd, Grinstein, and Lebed and using lattice QCD data from the FNAL/MILC and HPQCD collaborations, we find ηEW|Vcb|=(41.10±1.14)×10-3., 2016年02月25日, Physical Review D, 93 (3), 1-14, doi;scopus;scopus_citedby研究論文（学術雑誌）
Observation of B0 →p Λ ¯ D (∗)-
© 2015 American Physical Society. We report the first observation of the decays B0→pΛ¯D(∗)-. The data sample of 711 fb-1 used in this analysis corresponds to 772×106 BB¯ pairs, collected at the (4S) resonance by the Belle detector at the KEKB asymmetric-energy e+e- collider. We observe 19.8σ and 10.8σ excesses of events for the two decay modes and measure the branching fractions of B0→pΛ¯D- and B0→pΛ¯D∗- to be (25.1±2.6±3.5)×10-6 and (33.6±6.3±4.4)×10-6, respectively, where the first uncertainties are statistical and the second are systematic. These results are not compatible with the predictions based on the generalized factorization approach. In addition, a threshold enhancement in the dibaryon (pΛ¯) system is observed, consistent with that observed in similar B decays., 2015年11月24日, Physical Review Letters, 115 (22), 1-8, doi;scopus;scopus_citedby研究論文（学術雑誌）
Measurement of e+e- →γχcJ via initial state radiation at Belle
© 2015 American Physical Society. The process e+e-→γχcJ (J=1, 2) is studied via initial state radiation using 980fb-1 of data at and around the (nS) (n=1, 2, 3, 4, 5) resonances collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. No significant signal is observed except from ψ(2S) decays. Upper limits on the cross sections between s=3.80 and 5.56 GeV are determined at the 90% credibility level, which range from a few pb to a few tens of pb. We also set upper limits on the decay rate of the vector charmonium [ψ(4040), ψ(4160), and ψ(4415)] and charmoniumlike [Y(4260), Y(4360), and Y(4660)] states to γχcJ., 2015年06月17日, Physical Review D - Particles, Fields, Gravitation and Cosmology, 92 (1), arxiv;web_of_science;doi;arxiv_url;arxiv_url;url研究論文（学術雑誌）
Measurement of B0 → D-
© 2015 American Physical Society. We report a measurement of the B0 and B+ meson decays to the D-sK0Sπ+ and D-sK+K+ final states, respectively, using 657 × 106BB¯ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e+ collider. Using the D-s → φ π-, K∗(892)0K- and K0SK- decay modes for the Ds reconstruction, we measure the following branching fractions: B(B0 → D-sK0sπ+) = [0.47 ± 0.06(stat) ± 0.05(syst)] × 10-4 and B(B+ → D-sK+K+) = [0.93 ± 0.22(stat) ± 0.10(syst)] × 10-5. We find the ratio of the branching fraction of B+ → D-sK+K+ to that of the analogous Cabibbo-favored B+ → D-sK+π+ decay to be RB = 0.054 ± 0.013(stat) ± 0.006(syst), which is consistent with the naive factorization model. We also observe a deviation of the DsK invariant-mass distribution from the three-body phase-space model for both studied decays., 2015年02月26日, Physical Review D - Particles, Fields, Gravitation and Cosmology, 91 (3), 032008, doi;scopus;scopus_citedbys K0S π+ and B+ → D-s K+K+ branching fractions研究論文（学術雑誌）
Electromagnetic calorimeter for Belle II
The electromagnetic calorimeter of the BELLE II detector for experiments at Super B-factory SuperKEKB is briefly described. The project of the calorimeter upgrade to meet severe background conditions expected at the upgraded KEK B factory is presented., 2015年, 16TH INTERNATIONAL CONFERENCE ON CALORIMETRY IN HIGH ENERGY PHYSICS (CALOR 2014), 587, doi;web_of_science研究論文（国際会議プロシーディングス）
Observation of the decay B0 →η′K∗ (892)0
© 2014 American Physical Society. We report a search for charmless hadronic decays of neutral B mesons to η′K∗(892)0. The results are based on a 711fb-1 data sample that contains 772×106BB¯ pairs, collected at the (4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. We observe the decay for the first time with a significance of 5.0 standard deviations and obtain its branching fraction B[B0→η′K∗(892)0]=[2.6±0.7(stat)±0.2(syst)]×10-6. We also measure the CP-violating asymmetry as ACP[B0→η′K∗(892)0]=-0.22±0.29(stat)±0.07(syst)., 2014年10月, Physical Review D - Particles, Fields, Gravitation and Cosmology, 90 (7), web_of_science;doi;url研究論文（学術雑誌）
Upgrade of the Belle II electromagnetic calorimeter
The construction of the SuperKEKB electron-positron collider and upgrade of the Belle II spectrometer are going on at KEK aiming at high precision measurements in bottom, charm and tau flavor sectors. We describe a replacement of the electronics for the CsI(T-l) crystal calorimeter with PIN-PD readout to match the luminosity increase up to 8 x 10(35) cm(-2)s(-1) at maximum. A plan to replace CsI(T-l) crystals with pure CsI in the endcaps is also mentioned., 2014年09月, JOURNAL OF INSTRUMENTATION, 9, doi;web_of_science研究論文（学術雑誌）
Upgrade of trigger and DAQ for CsI at Belle II
The designed luminosity of the Belle detector after its upgrade (Belle II experiment) is 40 times higher than the maximum reached before its shutdown for an upgrade. This necessitates an upgrade of the Belle DAQ system together with the upgrade of many detector's subsystems. In this paper the upgrade of the Belle Electromagnetic calorimeter (ECL) electronics is described., 2014年09月, JOURNAL OF INSTRUMENTATION, 9, doi;web_of_science研究論文（学術雑誌）
Measurement of time-dependent CP violation in B0 → η′K0 decays
© 2014, The Author(s). Abstract: We present a measurement of the time-dependent CP violation parameters in B<sup>0</sup> → η′K<sup>0</sup> decays. The measurement is based on the full data sample containing 772 × 10<sup>6</sup> (Formula Presented.) pairs collected at the Υ(4S) resonance using the Belle detector at the KEKB asymmetric-energy e<sup>+</sup>e<sup>−</sup> collider. The measured values of the mixing-induced and direct CP violation parameters are: (Formula Presented.) (Formula Presented.) where the first uncertainty is statistical and the second is systematic. The values obtained are the most accurate to date. Furthermore, these results are consistent with our previous measurements and with the world-average value of sin 2ϕ<inf>1</inf> measured in B<sup>0</sup> → J/ψK<sup>0</sup> decays., 2014年08月26日, Journal of High Energy Physics, 2014 (10), arxiv;web_of_science;doi;arxiv_url;arxiv_url;url研究論文（学術雑誌）
Search for B+ → e+νe and B+ → μ+νμ decays using hadronic tagging
© 2015 American Physical Society. We present a search for the rare leptonic decays B+ → e+νe and B+ → μ+νμ, using the full Υ(4S) data sample of 772 × 106 B B¯ pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. One of the B mesons from the Υ(4S) → B B¯ decay is fully reconstructed in a hadronic mode, while the recoiling side is analyzed for the signal decay. We find no evidence of a signal in any of the decay modes. Upper limits of the corresponding branching fractions are determined as B(B+ → e+νe) < 3.5 × 10-6 and B(B+ → μ+νμ) < 2.7 × 10-6 at 90% confidence level., 2014年06月24日, Physical Review D - Particles, Fields, Gravitation and Cosmology, 91 (5), arxiv;web_of_science;doi;arxiv_url;arxiv_url;urlFirst observation of Cabibbo-suppressed Ξc0 decays
We report the first observation of the Cabibbo-suppressed decays Ξc0→Ξ-K+, Ξc0→ΛK +K- and Ξc0→Λφ, using a data sample of 711 fb-1 collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We measure the ratios of branching fractions to be B(Ξc0→Ξ -K+)B(Ξc0→Ξ-π+)=(2. 75±0.51±0.25)×10-2, B(Ξc0→ΛK +K-)B(Ξc0→Ξ-π+)=(2. 86±0.61±0.37)×10-2 and B(Ξc0→Λ φ)B(Ξc0→Ξ-π+)=(3.43±0. 58±0.32)×10-2, where the first uncertainty is statistical and the second is systematic. © 2013 American Physical Society., 2013年06月25日, Physical Review D - Particles, Fields, Gravitation and Cosmology, 88 (7), 1 - 71103, j_global;arxiv;web_of_science;doi;arxiv_url;arxiv_url;url研究論文（学術雑誌）
Search for B→h(*) νν̄ with the full Belle Υ(4S) data sample
We report a search for the rare decays B→h(*) νν̄, where h(z.ast;) stands for K+, KS0, K*+, K*0, π+, π0, ρ+, ρ0 and p. The results are obtained from a 711 fb-1 data sample that contains 772×106BB̄ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB e+e- collider. We search for signal candidates by fully reconstructing a hadronic decay of the accompanying B meson and requiring a single h(*) meson left on the signal side. No significant signal is observed and we set upper limits on the branching fractions at 90% confidence level. The measurements of B+→K *+νν̄, B+→π +νν̄, B0→π0νν̄ and B0→ρ0ν ν̄ provide the world's currently most restrictive limits. © 2013 American Physical Society., 2013年03月15日, Physical Review D - Particles, Fields, Gravitation and Cosmology, 87 (11), arxiv;web_of_science;doi;arxiv_url;arxiv_url;urlSearch for heavy neutrinos at Belle
We report on a search for heavy neutrinos in B-meson decays. The results are obtained using a data sample that contains 772×106BB̄ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. No signal is observed and upper limits are set on mixing of heavy neutrinos with left-handed neutrinos of the Standard Model in the mass range 0.5-5.0 GeV/c2. © 2013 American Physical Society., 2013年01月07日, Physical Review D - Particles, Fields, Gravitation and Cosmology, 87 (7), 1 - 71102, j_global;arxiv;web_of_science;doi;arxiv_url;arxiv_url;url研究論文（学術雑誌）
Evidence for B-→τ-ν̄τ with a hadronic tagging method using the full data sample of belle
We measure the branching fraction of B-→τ -ν̄τ using the full Υ(4S) data sample containing 772×106 BB̄ pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. Events with BB̄ pairs are tagged by reconstructing one of the B mesons decaying into hadronic final states, and B-→τ -ν̄τ candidates are detected in the recoil. We find evidence for B-→τ -ν̄τ with a significance of 3.0 standard deviations including systematic errors and measure a branching fraction B(B -→τ-ν̄τ)=[0.72-0.25+0. 27(stat)±0.11(syst)]×10-4. © 2013 American Physical Society., 2012年08月23日, Physical Review Letters, 110 (13), pubmed;arxiv;web_of_science;doi;arxiv_url;arxiv_url;urlObservation of D+→K+η(′ and search for CP violation in D+→π+η(′) decays
We report the first observation of the doubly Cabibbo-suppressed decays D+→K+η(′) using a 791fb-1 data sample collected with the Belle detector at the KEKB asymmetric-energy e +e- collider. The ratio of the branching fractions of doubly Cabibbo-suppressed relative to singly Cabibbo-suppressed D +→π+η(′) decays are B(D +→K+η)/B(D+→π+η )=(3.06±0.43±0.14)% and B(D+→K+η ′)/B(D+→π+η ′)=(3.77±0.39±0.10)%. From these, we find that the relative final-state phase difference between the tree and annihilation amplitudes in D+ decays, δTA, is (72±9)°or (288±9)°. We also report the most precise measurements of CP asymmetries to date: ACPD+→π +η=(+1.74±1.13±0.19)% and ACPD+→ π+η′=(-0.12±1.12±0.17)%. © 2011 American Physical Society., 2011年11月, Physical Review Letters, 107 (22), web_of_science;doi;url研究論文（学術雑誌）
Search for lepton-number-violating B+→D- +′+ decays
We perform the first search for lepton-number-violating B +→D-+′+ decays, where and ′ stand for e or μ, using 772×106 BB̄ pairs accumulated at the Υ(4S) resonance with the Belle detector at the KEKB e+e- collider. No evidence for these decays has been found. Assuming uniform three-body phase space distributions for the D-+′+ decays, we set the following upper limits on the branching fractions at 90% confidence level: B(B+→D-e+e+)<2. 6×10-6, B(B+→D-e+μ +)<1.8×10-6 and B(B+→D -μ+μ+)<1.1×10-6. © 2011 American Physical Society., 2011年10月, Physical Review D - Particles, Fields, Gravitation and Cosmology, 84 (7), web_of_science;doi;url研究論文（学術雑誌）
Bounds on the width, mass difference and other properties of X(3872) → π+π-J/ψ decays
© 2011 American Physical Society. We present results from a study of X(3872) → ππJ/ψ decays produced via exclusive B → KX(3872) decays. We determine the mass to be MX(3872)= (3871.85 ± 0.27(stat) ± 0.19(syst)) MeV, a 90% confidence level upper limit on the natural width of ΓX(3872)< 1.2 MeV, the product branching fraction B(B+→ K+X(3872)) X B(X(3872) → π+π-J/ψ) = (8.63±0.82(stat)±0.52(syst)) × 10-6, and a ratio of branching fractions B(B0→ K0X(3872))/B(B+→ K+X(3872)) = 0.50±0.14(stat) ±0.04(syst). The difference in mass between the X(3872) → π+π-J/ψ signals in B+and B0decays is ΔMX(3872)= (-0.71 ± 0.96(stat) ± 0.19(syst)) MeV. A search for a charged partner of the X(3872) in the decays B¯0→ K-X+or B+→ K0X+, X+→ π+π0J/ψ resulted in upper limits on the product branching fractions for these processes that are well below expectations for the case that the X(3872) is the neutral member of an isospin triplet. In addition, we examine possible JPCquantum number assignments for the X(3872) based on comparisons of angular correlations between final state particles in X(3872) → π+π-J/ψ decays with simulated data for JPCvalues of 1++and 2-+. We examine the influence of ρ-ω interference in the M(π+π-) spectrum. The analysis is based on a 711 fb-1data sample that contains 772 × 106BB¯ meson pairs collected at the Γ(4S) resonance in the Belle detector at the KEKB e+e-collider., 2011年09月07日, Physical Review D - Particles, Fields, Gravitation and Cosmology, 84 (5), 1-15, doi;scopus;scopus_citedby研究論文（学術雑誌）
Observation of Bs0→J/ψf0(980) and evidence for Bs0→J/ψf0(1370)
We report the observation of Bs0→J/ψf0(980) and evidence for Bs0→J/ψf0(1370), which are CP eigenstate decay modes. These results are obtained from 121.4fb-1 of data collected at the Υ(5S) resonance with the Belle detector at the KEKB e +e- collider. We measure the branching fractions B(Bs0→J/ψf0(980);f0(980) →π+π-)=(1.16-0.19+0.31(stat)-0.17+0.15(syst)-0. 18+0.26(NBs(*)B̄s(*)))×10-4 with a significance of 8.4σ, and B(Bs0→J/ψf0(1370);f 0(1370)→π+π-)=(0.34-0.14+0.11(stat) -0.02+0.03(syst)-0.05+0.08(NBs(*)B̄s(*))) ×10-4 with a significance of 4.2σ. The last error listed is due to uncertainty in the number of produced Bs(*)B̄s(*) pairs. © 2011 American Physical Society., 2011年03月, Physical Review Letters, 106 (12), web_of_science;doi;url研究論文（学術雑誌）
Radiation hardness test of Pr:LuAG and BSO scintillators
We measured radiation hardness of two kinds of newly developed inorganic scintillators, Pr:LuAG and BSO. The amounts of irradiation for our test were -rays up to 100 Gy and neutrons up to 1012 neutrons/cm2 fluence. These radiation doses are corresponding to SuperKEKB/Belle-II 10 years operation. For -rays, both Pr:LuAG and BSO scintillators showed reasonably good radiation hardness, (113)% and (63)%, respectively, for 100 Gy. For neutrons, at 1011 neutrons/cm2, light output degradation was 6% in both scintillators. At 1012 neutrons/cm2, BSO is still found to be robust, light output decrease is 8%, while Pr:LuAG shows 36% degradation. © 2010 IEEE., 2010年, IEEE Nuclear Science Symposium Conference Record, 278 - 279, doi研究論文（国際会議プロシーディングス）
Effects of radiation damage caused by proton irradiation on Multi-Pixel Photon Counters (MPPCs)
We have investigated the effects caused by proton-induced radiation damage on Multi-Pixel Photon Counter (MPPC), a pixelized photon detector developed by Hamamatsu Photonics. The leakage current of irradiated MPPC samples linearly increases with total irradiated doses due to radiation damage, which is not completely recovered even after a year from the irradiation. No significant change has been observed in the gains at least up to 8.0 Gy (9.1 × 107 n / mm2 in 1 MeV neutron equivalent fluence, Φeq). The device has completely lost its photon-counting capability due to baseline fluctuations and noise pile-up after 21 Gy irradiation (2.4 × 108 n / mm2 in Φeq), which might be problematic for some applications, such as ring-imaging Cherenkov detectors. We have found that the pulse-height resolution has been slightly deteriorated after 42 Gy irradiation (4.8 × 108 n / mm2 in Φeq), where the measured sample has been illuminated with a few hundred photons. This effect should be considered in the case of energy-measurement applications. © 2009 Elsevier B.V. All rights reserved., 2009年05月21日, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 603 (3), 301 - 308, doi研究論文（学術雑誌）
Evidence for the ηb(2S) and observation of h b(1P)→ηb(1S)γ and hb(2P) →ηb(1S)γ
We report the first evidence for the ηb(2S) using the h b(2P)→ηb(2S)γ transition and the first observation of the hb(1P)→ηb(1S)γ and hb(2P)→ηb(1S)γ transitions. The mass and width of the ηb(1S) and ηb(2S) are measured to be mηb (1S)=(9402.4±1.5±1.8) MeV/c2, m ηb (2S)=(9999.0±3.5-1.9+2.8) MeV/c2, and Γηb (1S)=(10.8-3.7-2.0+4.0+4.5) MeV. We also update the hb(1P) and hb(2P) mass measurements. We use a 133.4 fb-1 data sample collected at energies near the γ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+e - collider. © 2012 American Physical Society., 2009年02月19日, Physical Review Letters, 109 (23), web_of_science;doi;urlBelle electromagnetic calorimeter
We report the performance of the Belle electromagnetic calorimeter for the first three years operation. Good mass resolutions for π0 and η are obtained to be 4.8 and 12.1 MeV/c2, respectively. The degradation of light output due to the radiation damage is small, about 3% for the radiation dose of 40 rad. These performances promise further study of B physics with neutral particle reconstruction. © 2002 Elsevier Science B.V. All rights reserved., 2002年11月21日, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 494 (1-3), 298 - 302, doi研究論文（国際会議プロシーディングス）
Study of exclusive Beta decays to charmed baryons
Using 29.1 fb -1 of data accumulated at the γ(4S) with the Belle detector at KEKB, we have studied the decay modes B̄ 0→Λ c+p̄π + π -→ B -→Λ c+p̄π -, and B̄ 0→Λ c+p̄. We report branching fractions of exclusive B decays to charmed baryons with four-, three- and two-body final states, including intermediate ∑ c++ and ∑ c0 states. We observed B̄ 0→∑ c2(2455) ++p̄π - for the first time with a branching fraction of (2.38 -0.55+0.63±0.41 ±0.62)×10 -4 and observed evidence for the two-body decay B -→∑ c(2455) 0p̄ with a branching fraction of (0.45 -0.19+0.26±0.07±0.12) ×10 -4. We also set improved upper limits for the two-body decays B̄ 0→Λ c+p̄ and B̄ -→∑ c(2520) 0p̄. © 2002 The American Physical Society., 2002年11月, PHYSICAL REVIEW D, 66 (9), doi;web_of_science;url研究論文（学術雑誌）
Measurement of the jet width in γγ collisions and in e+e- annihilation process at TRISTAN
The shape of jets produced in (quasi-) real photon-photon collisions as well as in e+e- annihilation process has been studied with a cone jet finding algorithm, using the data taken with the TOPAZ detector at the TRISTAN e+e- collider at an average center-of-mass energy (√see) of 58 GeV. The results are presented in terms of the jet width as a function of the jet transverse energy (ETjet) as well as a scaled transverse jet energy, XT( = 2ETjet/√s)- The jet width narrows as ETjet increases; however, at the same value of ETjet the jet width in γγ collisions at TRISTAN is significantly narrower than that in γp collisions at HERA. By comparing our results with the data in other reactions, it has been shown that the jet width in γγ, γp, pp̄ collisions as well as the e+e- annihilation process has an approximate scaling behavior as a function of XT. © 1999 Elsevier Science B.V. All rights reserved., 1999年, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 451 (1-2), 256 - 266, doi;url研究論文（学術雑誌）
e+e-反応における強い結合定数αsの測定
The strong coupling constant αs was determined from analyses of the thrust, heavy jet mass and, differential 2-jet rate, using e+e- hadronic events at s = 58 GeV with the TOPAZ detector at TRISTAN. The NLLjet Monte Carlo simulation (NLLjet) and analytic formulae based on resummation up to the next-to-leading logarithms combined with O(α2 s) calculations were used to evaluate αs. The average αs values at Q2 = (58 GeV)2 from the analyses are αs = 0.125 ± 0.009 for NLLjet and αs = 0.132 ± 0.008 for the resummed analytic formulae. © 1993., 1993年09月02日, フィジックス・レター, 313 (3-4), 475 - 482, doi研究論文（学術雑誌）
CsI(Tl) pulse shape discrimination with the Belle II electromagnetic calorimeter as a novel method to improve particle identification at electron–positron colliders
2020年12月, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 982, 164562 - 164562, doi研究論文（学術雑誌）
Production cross sections of hyperons and charmed baryons from e+e- annihilation near s =10.52 GeV
© 2018 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP 3 . We measure the inclusive production cross sections of hyperons and charmed baryons from e+e- annihilation using a 800 fb-1 data sample taken near the (4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. The feed-down contributions from heavy particles are subtracted using our data, and the direct production cross sections are presented for the first time. The production cross sections divided by the number of spin states for S=-1 hyperons follow an exponential function with a single slope parameter except for the Σ(1385)+ resonance. Suppression for Σ(1385)+ and Ξ(1530)0 hyperons is observed. Among the production cross sections of charmed baryons, a factor of 3 difference for Λc+ states over Σc states is observed. This observation suggests a diquark structure for these baryons., 2018年04月, Physical Review D, 97 (7), 072005, doi;scopus;scopus_citedby研究論文（学術雑誌）
Measurements of the absolute branching fractions of B + → X
© 2018 authors. Published by the American Physical Society. We present the measurement of the absolute branching fractions of B+→Xcc̄K+ and B+→D̄(∗)0π+ decays, using a data sample of 772×106 BB̄ pairs collected at the (4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. Here, Xcc̄ denotes ηc, J/ψ, χc0, χc1, ηc(2S), ψ(2S), ψ(3770), X(3872), and X(3915). We do not observe significant signals for X(3872) or X(3915) and set the 90% confidence level upper limits at B(B+→X(3872)K+)<2.6×10-4 and B(B+→X(3915)K+)<2.8×10-4. These represent the most stringent upper limit for B(B+→X(3872)K+) to date and the first limit for B(B+→X(3915)K+). The measured branching fractions for ηc and ηc(2S) are the most precise to date, B(B+→ηcK+)=(12.0±0.8±0.7)×10-4 and B(B+→ηc(2S)K+)=(4.8±1.1±0.3)×10-4, where the first and second uncertainties are statistical and systematic, respectively., 2018年01月01日, Physical Review D, 97 (1), 012005, doi;scopus;scopus_citedbycc̄ K + and B + → D̄ (*)0 π + at Belle研究論文（学術雑誌）
Measurement of the τ lepton polarization and R(D*) in the decay B¯→D*τ−ν¯τ with one-prong hadronic τ decays at Belle
© 2018 authors. Published by the American Physical Society. With the full data sample of 772×106 BB̄ pairs recorded by the Belle detector at the KEKB electron-positron collider, the decay B̄→D∗τ-ν̄τ is studied with the hadronic τ decays τ-→π-ντ and τ-→ρ-ντ. The τ polarization Pτ(D∗) in two-body hadronic τ decays is measured, as well as the ratio of the branching fractions R(D∗)=B(B̄→D∗τ-ν̄τ)/B(B̄→D∗-ν̄), where - denotes an electron or a muon. Our results, Pτ(D∗)=-0.38±0.51(stat)-0.16+0.21(syst) and R(D∗)=0.270±0.035(stat)-0.025+0.028(syst), are consistent with the theoretical predictions of the standard model. The polarization values of Pτ(D∗)>+0.5 are excluded at the 90% confidence level., 2018年01月01日, Physical Review D, 97 (1), 012004, doi;scopus;scopus_citedby研究論文（学術雑誌）
Evidence for Isospin Violation and Measurement of CP Asymmetries in B -> K*(892)gamma
We report the first evidence for isospin violation in B -> K*gamma and the first measurement of the difference of CP asymmetries between B+->.K*(+)gamma and B-0 -> K-*0 gamma. This analysis is based on the data sample containing 772 x 10(6)BB pairs that was collected with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. We find evidence for the isospin violation with a significance of 3.1 sigma, Delta(0+) = [+6.2 +/- 1.5(stat) +/- 0.6(syst) +/- 1.2(f (+-)/f(00))] %, where the third uncertainty is due to the uncertainty on the fraction of B+B- to (BB0)-B-0 production in gamma(4S) decays. The measured value is consistent with predictions of the standard model. The result for the difference of CP asymmetries is Delta A(CP) = [+2.4 +/- 2.8(stat) +/- 0.5(syst)] %, consistent with zero. The measured branching fractions and CP asymmetries for charged and neutral B meson decays are the most precise to date. We also calculate the ratio of branching fractions of B-0 -> K-*0 gamma to B-s(0) -> phi gamma., 2017年11月, PHYSICAL REVIEW LETTERS, 119 (19), 111801, doi;web_of_science研究論文（学術雑誌）
Search for Lambda(+)(c) -> phi p pi(0) and branching fraction measurement of Lambda(+)(c) -> K- pi(+) p pi(0)
We have searched for the Cabibbo-suppressed decay Lambda(+)(c) -> pi p(0) in e(+) e(-) collisions using a data sample corresponding to an integrated luminosity of 915 fb(-1). The data were collected by the Belle experiment at the KEKB e(+) e(-) asymmetric-energy collider running at or near the (4S) and (5S) resonances. No significant signal is observed, and we set an upper limit on the branching fraction of B(Lambda(+)(c) -> phi p(0)) < 15.3 x 10(-5) at 90% confidence level. The contribution of nonresonant Lambda(+)(c) -> K+ K- p pi(0) decays is found to be consistent with zero, and the corresponding upper limit on its branching fraction is set to be B(Lambda(+)(c) ->. K+ K- p pi(0))(NR) < 6.3 x 10(-5) at 90% confidence level. We also search for an intermediate hidden-strangeness pentaquark decay P-s(+) -> phi p. We see no evidence for this intermediate decay and set an upper limit on the product branching fraction of B(Lambda(+)(c) -> P-s(+) pi(0)) x B(P-s(+) -> phi p) < 8.3 x 10(-5) at 90% confidence level. Finally, we measure the branching fraction for the Cabibbo-favored decay Lambda(+)(c) -> K- pi(+) p pi(0); the result is B(Lambda(+)(c) -> K- pi(+) p pi(0)) = (4.42 +/- 0.05(stat)+/- 0.12(syst)+/- 0.16(norm))%, which is the most precise measurement to date., 2017年09月, PHYSICAL REVIEW D, 96 (5), 051102, doi;web_of_science研究論文（学術雑誌）
Invariant-mass and fractional-energy dependence of inclusive production of dihadrons in e(+) e(-) annihilation at root s=10.58 GeV
The inclusive cross sections for dihadrons of charged pions and kaons (e(+)e(-) -> hhX) in electron-positron annihilation are reported. They are obtained as a function of the total fractional energy and invariant mass for any di-hadron combination in the same hemisphere as defined by the thrust event-shape variable and its axis. Since same-hemisphere dihadrons can be assumed to originate predominantly from the same initial parton, di-hadron fragmentation functions are probed. These di-hadron fragmentation functions are needed as an unpolarized baseline in order to quantitatively understand related spindependent measurements in other processes and to apply them to the extraction of quark transversity distribution functions in the nucleon. The di- hadron cross sections are obtained from a 655 fb(-1) data sample collected at or near the Y (4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider., 2017年08月, PHYSICAL REVIEW D, 96 (3), 032005, doi;web_of_science研究論文（学術雑誌）
Measurement of branching fraction and direct CP asymmetry in charmless B+ -> K+ K- pi(+) decays at Belle
We report a study of the charmless hadronic decay of the charged B meson to the three-body final state K+K-pi(+). The results are based on a data sample that contains 772 x 10(6) B (B) over bar pairs collected at the Y (4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The measured inclusive branching fraction and direct CP asymmetry are (5.38 +/- 0.40 +/- 0.35) x 10(-6) and -0.170 +/- 0.073 +/- 0.017, respectively, where the first uncertainties are statistical and the second are systematic. The K+K- invariant mass distribution of the signal candidates shows an excess in the region below 1.5 GeV/c(2), which is consistent with the previous studies from BABAR and LHCb. In addition, strong evidence of a large direct CP asymmetry is found in the low K+K- invariant-mass region., 2017年08月, PHYSICAL REVIEW D, 96 (3), 031101, doi;web_of_science研究論文（学術雑誌）
Observation of an alternative chi(c0)(2P) candidate in e(+)e(-)-> J/psi D(D)over-bar
We perform a full amplitude analysis of the process e(+)e(-)-> J/psi D (D) over bar, where D refers to either D-0 or D+. A new charmoniumlike state X*(3860) that decays to D (D) over bar is observed with a significance of 6.5 sigma. Its mass is (3862(-32)(+26) (+40)(-13) )MeV= c(2), and its width is (201(-67) (+154)(-82) (+88)) MeV. The J(PC) = 0(++) hypothesis is favored over the 2(++) hypothesis at the level of 2.5s. The analysis is based on the 980 fb(-1) data sample collected by the Belle detector at the asymmetric-energy e(+)e(-)collider KEKB., 2017年06月, PHYSICAL REVIEW D, 95 (11), 112003, doi;web_of_science研究論文（学術雑誌）
Measurement of the tau Lepton Polarization and R(D*) in the Decay (B)over-bar -> D* tau(-) (v)over-bar(tau)
We report the first measurement of the tau lepton polarization P-tau(D*) in the decay (B) over bar -> D* tau(-) (v) over bar (tau) as well as a newmeasurement of the ratio of the branching fractions R(D*) = B((B) over bar -> D* tau(-) (v) over bar (tau)) / B((B) over bar -> D* l(-) (v) over bar (l)), where l(-) denotes an electron or a muon, and the tau is reconstructed in the modes tau(-) -> pi(-) v(tau) and tau(-) -> rho(-) v(tau). We use the full data sample of 772 x 10(6) B (B) over bar pairs recorded with the Belle detector at the (KEKB) over bar electron-positron collider. Our results, P-tau(D*) = -0.38 +/- 0.51 (stat)(-0.16)(+0.21) (syst) and R(D*) = 0.270 +/- 0.035 (stat)(- 0.025)(+0.028) (syst), are consistent with the theoretical predictions of the standard model., 2017年05月, PHYSICAL REVIEW LETTERS, 118 (21), 211801, doi;web_of_science研究論文（学術雑誌）
Lepton-Flavor-Dependent Angular Analysis of B -> K*l(+)l(-)
We present a measurement of angular observables and a test of lepton flavor universality in the B -> K(+)l(+)l(-) decay, where l is either e or mu. The analysis is performed on a data sample corresponding to an integrated luminosity of 711 fb(-1) containing 772 x 10(6) B (B) over bar pairs, collected at the Upsilon(4S) resonance with the Belle detector at the asymmetric-energy e(+)e(-) collider KEKB. The result is consistent with standard model (SM) expectations, where the largest discrepancy from a SM prediction is observed in the muon modes with a local significance of 2.6 sigma., 2017年03月, PHYSICAL REVIEW LETTERS, 118 (11), 111801, doi;web_of_science研究論文（学術雑誌）
Search for D-0 decays to invisible final states at Belle
We report the result from the first search for D-0 decays to invisible final states. The analysis is performed on a data sample of 924 fb(-1) collected at and near the gamma(4S) and gamma(5S) resonances with the Belle detector at the KEKB asymmetric-energy e(|) e(-) collider. The absolute branching fraction is determined using an inclusive D-0 sample, obtained by fully reconstructing the rest of the particle system including the other charmed particle. No significant signal yield is observed and an upper limit of 9.4 x 10(-5) is set on the branching fraction of D-0 to invisible final states at 90% confidence level., 2017年01月, PHYSICAL REVIEW D, 95 (1), 011102, doi;web_of_science研究論文（学術雑誌）
Observation of D-0 -> rho(0)gamma and Search for CP Violation in Radiative Charm Decays
We report the first observation of the radiative charm decay D-0 -> rho(0)gamma and the first search for CP violation in decays D-0 -> rho(0)gamma, phi gamma, and (K) over bar (*0)(892)gamma, using a data sample of 943 fb(-1) collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The branching fraction is measured to be B(D-0 -> rho(0)gamma) = (1.77 +/- 0.30 +/- 0.07) x 10(-5), where the first uncertainty is statistical and the second is systematic. The obtained CP asymmetries A(CP)(D-0 ->rho(0)gamma) = +0.056 +/- 0.152 +/- 0.006, A(CP)(D-0 -> phi gamma) = -0.094 +/- 0.066 +/- 0.001, and A(CP)(D-0 -> (K) over bar (*0) gamma = -0.003 +/- 0.020 +/- 0.000 are consistent with no CP violation. We also present an improved measurement of the branching fractions B(D-0 -> phi gamma) = (2.76 +/- 0.19 +/- 0.10) x 10(-5) and B(D-0 -> (K) over bar (*0) gamma = (4.66 +/- 0.21 +/- 0.21) x 10(-4)., 2017年01月, PHYSICAL REVIEW LETTERS, 118 (5), 051801, doi;web_of_science研究論文（学術雑誌）
Measurement of the branching ratio of (B)over-bar(0) -> D*(+)tau(-)(nu)over-bar(tau) relative to (B)over-bar(0) -> D*(+)l(-)(nu)over-bar(l) decays with a semileptonic tagging method
We report a measurement of the ratio R(D*) = B((B) over bar (0) -> D*(+)tau(-)(nu) over bar (tau))/B((B) over bar (0) -> D*(+)l(-)(nu) over bar (l))where l denotes an electron or a muon. The results are based on a data sample containing 772 x 10(6) B (B) over bar pairs recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) collider. We select a sample of B-0(B) over bar (0) pairs by reconstructing both B mesons in semileptonic decays to D*(-/+)l(+/-). We measure R(D*) = 0.302 +/- 0.030(stat) +/- 0.011(syst), which is within 1.6 sigma of the Standard Model theoretical expectation, where the standard deviation sigma includes systematic uncertainties. We use this measurement to constrain several scenarios of new physics in a model-independent approach., 2016年10月, PHYSICAL REVIEW D, 94 (7), 072007, doi;web_of_science研究論文（学術雑誌）
Measurement of the CKM angle phi(1) in B-0 -> (D)over-bar(*)(0)h(0), (D)over-bar(0) -> K-S(0)pi(+)pi(-) decays with time-dependent binned Dalitz plot analysis
We report a measurement of the CP-violation parameter phi(1) obtained in a time-dependent analysis of B-0 -> (D) over bar(*)(0)h(0) decays followed by (D) over bar (0) -> K-S(0)pi(+)pi decay. A model-independent measurement is performed using the binned Dalitz plot technique. The measured value is phi(1) = 11.7 degrees +/- 7.8 degrees(stat) +/- 2.1 degrees (syst). Treating sin 2 phi(1) and cos 2 phi(1) as independent parameters, we obtain sin 2 phi(1) = 0.43 +/- 0.27(stat) +/- 0.08(syst) and cos 2 phi(1) = 1.06 +/- 0.33(stat)(-0.15)(+0.21)(syst). The results are obtained with a full data sample of 772 x 10(6)B (B) over bar pairs collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider., 2016年09月, PHYSICAL REVIEW D, 94 (5), 052004, doi;web_of_science研究論文（学術雑誌）
Study of excited Xi(c) states decaying into Xi(0)(c) and Xi(+)(c) baryons
Using a data sample of 980 fb(-1) of e(+)e(-) annihilation data taken with the Belle detector operating at the KEKB asymmetric-energy e(+)e(-) collider, we report the results of a study of excited Xi(c) states that decay, via the emission of photons and/or charged pions, into Xi(0)(c) or Xi(+)(c) ground state charmed-strange baryons. We present new measurements of the masses of all members of the Xi(0)(c), Xi(c)(2645), Xi(c)(2790), Xi(c)(2815), and Xi(c)(2980) isodoublets, measurements of the intrinsic widths of those that decay strongly, and evidence of previously unknown transitions., 2016年09月, PHYSICAL REVIEW D, 94 (5), 052001, doi;web_of_science研究論文（学術雑誌）
First observation of γγ →p p K+K- and search for exotic baryons in pK systems
© 2016 American Physical Society. The process γγ→ppK+K- and its intermediate processes are measured for the first time using a 980 fb-1 data sample collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The production of ppK+K- and a Λ(1520)0 (Λ(1520)0) signal in the pK- (pK+) invariant mass spectrum are clearly observed. However, no evidence for an exotic baryon near 1540 MeV/c2, denoted as Θ(1540)0 (Θ(1540)0) or Θ(1540)++ (Θ(1540) - ), is seen in the pK- (pK+) or pK+ (pK-) invariant mass spectra. Cross sections for γγ→ppK+K-, Λ(1520)0pK++c.c. and the products σ(γγ→Θ(1540)0pK++c.c.)B(Θ(1540)0→pK-) and σ(γγ→Θ(1540)++pK-+c.c.)B(Θ(1540)++→pK+) are measured. We also determine upper limits on the products of the χc0 and χc2 two-photon decay widths and their branching fractions to ppK+K- at the 90% credibility level., 2016年06月, Physical Review D, 93 (11), web_of_science;doi;url研究論文（学術雑誌）
First Observation of the Doubly Cabibbo-Suppressed Decay of a Charmed Baryon: Λc+ →pK+π-
© 2016 American Physical Society. We report the first observation of the decay Λc+→pK+π- using a 980 fb-1 data sample collected by the Belle detector at the KEKB asymmetric-energy e+e- collider. This is the first observation of a doubly Cabibbo-suppressed decay of a charmed baryon. We measure the branching ratio of this decay with respect to its Cabibbo-favored counterpart to be B(Λc+→pK+π-)/B(Λc+→pK-π+)=(2.35±0.27±0.21)×10-3, where the uncertainties are statistical and systematic, respectively., 2016年06月, Physical Review Letters, 117 (1), web_of_science;doi;url研究論文（学術雑誌）
Exotic hadrons with heavy flavors: X, Y, Z, and related states
both in experiments and in theories. In this review, we provide topical discussions by selecting X, Y, Z particles, to which Belle has made important contributions. These are X(3872), Y (4260), Z(c)(4430)(+), Z(c)(3900)(+), Z(b)(10610)(+), and Z(b)(10650)(+). Based on the current experimental observations, we discuss these states with emphasis on the hadronic molecule whose dynamics is governed by chiral symmetry and heavy-quark symmetry of QCD. We also mention briefly various interpretations and some theoretical predictions for the as yet undiscovered exotic hadrons., 2016年06月, PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS, 2016 (6), 062C01, doi;web_of_science研究論文（学術雑誌）
First model-independent Dalitz analysis of B0 → DK∗0, D → KS π+π-decay
© 2016 The Author(s). We report a measurement of the amplitude ratio rS of B → DK∗and B → D K∗decays with a Dalitz analysis of D → KS 0π +π-decays, for the first time using a modelindependent method. We set an upper limit rS < 0.87 at the 68% confidence level, using the full data sample of 711 fb-1 corresponding to 772 × 106 BB pairs collected at the (4S) resonance with the Belle detector at the KEKB e+e-collider. This result is obtained from observables x-= +0.4+1.0+0.0-0.6-0.1 ± 0.0, y-=-0.6+-0 1.8 0+-0 0.1 0 ± 0.1, x+ = +0.1+-0 0.7 4+-0 0.0 1 ± 0.1, and y+ = +0.3+-0 0.5 8+-0 0.0 1 ± 0.1, where x± = rS cos(dS ± f3), y± = rS sin(dS ± f3), and f3 (dS) is the weak (strong) phase difference between B → DK∗and B → D K ∗0., 2016年04月, Progress of Theoretical and Experimental Physics, 2016 (4), web_of_science;doi;url研究論文（学術雑誌）
Inclusive and exclusive measurements of B decays to chi(c1) and chi(c2) at Belle
We report inclusive and exclusive measurements for chi(c1) and chi(c2) production in B decays. We measure B(B -> chi X-c1) = (3.03 +/- 0.05 (stat) +/- 0.24(syst)) x 10(-3) and B(B -> chi X-c2) = (0.70 +/- 0.06 (stat) +/- 0.10(syst)) x 10(-3). For the first time, chi(c2) production in exclusive B decays in the modes B-0 -> chi(c2) pi K--(+) and B-0 -> chi(c2) pi(-)pi K-+(+) has been observed, along with first evidence for the B-0 -> chi(c2) pi K--(s)0 decay mode. For chi c1 production, we report the first observation in the B+ -> chi(c1) pi(-)pi K-+(+), B-0 -> chi(c1) pi(-)pi K-+(s)0 and B-0 -> chi(c1) pi(-)pi K-+(+) decay modes. Using these decay modes, we observe a difference in the production mechanism of chi(c2) in comparison to chi(c1) in B decays. In addition, we report searches for X(3872) and chi(c1) (2P) in the B+ -> (chi(c1) pi(+)pi(-))K+ decay mode. The reported results use 772 x 10(6) B (B) over bar events collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider., 2016年03月, PHYSICAL REVIEW D, 93 (5), 052016, doi;web_of_science研究論文（学術雑誌）
Measurement of D0-D0 mixing and search for CP violation in D0→K+K-,π+π- decays with the full Belle data set
© 2015 The Authors. We report an improved measurement of D0D0 mixing and a search for CP violation in D0 decays to CP-even final states K+K- and π+π-. The measurement is based on the final Belle data sample of 976 fb-1. The results are yCP=(1.11±0.22±0.09)% and AΓ=(-0.03±0.20±0.07)%, where the first uncertainty is statistical and the second is systematic., 2016年02月, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 753, 412 - 418, web_of_science;doi;url研究論文（学術雑誌）
Study of pi(0) pair production in single-tag two-photon collisions
We report a measurement of the differential cross section of pi(0) pair production in single-tag two-photon collisions, gamma*gamma -> pi(0) pi(0), in e(+) e(-) scattering. The cross section is measured for Q(2) up to 30 GeV2, where Q(2) is the negative of the invariant mass squared of the tagged photon, in the kinematic range 0.5 GeV < W < 2.1 GeV and vertical bar cos theta*vertical bar < 1.0 for the total energy and pion scattering angle, respectively, in the gamma*gamma center-of-mass system. The results are based on a data sample of 759 fb(-1) collected with the Belle detector at the KEKB asymmetric-energy e(+) e(-) collider. The transition form factor of the f(0)(980) and that of the f(2)(1270) with the helicity-0, -1, and -2 components separately are measured for the first time and are compared with theoretical calculations., 2016年02月, PHYSICAL REVIEW D, 93 (3), 032003, doi;web_of_science研究論文（学術雑誌）
Search for B-0 -> pi(-)tau(+)nu(tau) with hadronic tagging at Belle
We search for the process B-0 -> pi(-) tau(+)nu(tau) using the full Belle data set of 711 fb(-1), corresponding to 772 x 10(6)B (B) over bar pairs, collected at the gamma (4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We reconstruct one B meson in a hadronic decay and search for the B-0 -> pi(-)tau(+)nu(tau) process in the remainder of the event. No significant signal is observed and an upper limit of B(B-0 -> pi(-) tau(+)nu(tau)) < 2.5 x 10(-4) is obtained at the 90% confidence level., 2016年02月, PHYSICAL REVIEW D, 93 (3), 052016, doi;web_of_science研究論文（学術雑誌）
First observation of the decay B-0 -> psi(2S)pi(0)
We report a measurement of the B-0 -> psi(2S)pi(0) branching fraction based on the full Upsilon(4S) data set of 772 x 10(6) B (B) over bar pairs collected by the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We obtain B(B-0 -> psi(2S)pi(0)) = (1.17 +/- 0.17(stat) +/- 0.08(syst)) x 10(-5). The result has a significance of 7.2 standard deviations and is the first observation of the decay B-0 -> psi(2S)pi(0)., 2016年02月, PHYSICAL REVIEW D, 93 (3), 031101, doi;web_of_science研究論文（学術雑誌）
Study of B-0 -> rho(+)rho(-) decays and implications for the CKM angle phi(2)
We present a measurement of the branching fraction and the longitudinal polarization fraction of B-0 -> rho(+)rho(-) decays, as well as the time-dependent CP violating parameters in decays into longitudinally polarized rho(+)rho(-) pairs with Belle's final data set of 772 x 10(6) B (B) over bar pairs, at the Upsilon(4S) resonance, collected at the asymmetric-energy e(+)e(-) collider KEKB. We obtain B(B-0 -> rho(+)rho(-)) = (28.3 +/- 1.5(stat) +/- 1.5(syst)) x 10(-6), f(L) = 0.988 +/- 0.012(stat) +/- 0.023(syst), A(CP) = 0.00 +/- 0.10(stat) +/- 0.06(syst), S-CP = -0.13 +/- 0.15(stat) +/- 0.05(syst). We perform an isospin analysis to constrain the Cabibbo-Kobayashi-Maskawa angle phi(2) and obtain two solutions with phi(2) = (93.7 +/- 10.6)degrees, being most compatible with other Standard-Model based fits to the data., 2016年02月, PHYSICAL REVIEW D, 93 (3), 032010, doi;web_of_science研究論文（学術雑誌）
Measurement of the branching ratio of (B)over-bar -> D-(*())tau(-)(nu)over-bar(tau) relative to (B)over-bar -> D(*)l(-)(nu)over-bar(l) decays with hadronic tagging at Belle
We report a measurement of the branching fraction ratios R(D)(()*()) of (B) over bar -> D-(*())tau(-)(nu) over bar (tau) relative to (B) over bar -> D-(*())l(-)(nu) over barl (where l = e or mu) using the full Belle data sample of 772 x 10(6)B (B) over bar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The measured values are R(D) = 0.375 +/- 0.064(stat) +/- 0.026(syst) and R(D*) = 0.293 +/- 0.038 (stat) +/- 0.015 (syst). The analysis uses hadronic reconstruction of the tag-side B meson and purely leptonic t decays. The results are consistent with earlier measurements and do not show a significant deviation from the standard model prediction., 2015年10月, PHYSICAL REVIEW D, 92 (7), 072014, doi;web_of_science研究論文（学術雑誌）
First Observation of CP Violation in (B)over-bar(0) -> D(CP)((*))h(0) Decays by a Combined Time-Dependent Analysis of BABAR and Belle Data
We report a measurement of the time-dependent CP asymmetry of (B) over bar (0) -> D(CP)((*))h(0) decays, where the light neutral hadron h(0) is a pi(0), eta , or omega meson, and the neutral D meson is reconstructed in the CP eigenstates K+K-, K-S(0)pi(0) or K-S(0)omega. The measurement is performed combining the final data samples collected at the Upsilon(4S) resonance by the BABAR and Belle experiments at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471 +/- 3) x 10(6) B (B) over bar pairs recorded by the BABAR detector and (772 +/- 11) x 10(6) B (B) over bar pairs recorded by the Belle detector. We measure the CP asymmetry parameters -eta S-f = +0.66 +/- 0.10(stat) +/- 0.06(syst) and C = -0.02 +/- 0.07(stat) +/- 0.03(syst). These results correspond to the first observation of CP violation in (B) over bar (0) -> D(CP)((*))h(0) decays. The hypothesis of no mixing-induced CP violation is excluded in these decays at the level of 5.4 standard deviations., 2015年09月, PHYSICAL REVIEW LETTERS, 115 (12), 121604, doi;web_of_science研究論文（学術雑誌）
First Observation of the Hadronic Transition Upsilon(4S) -> eta h(b)(1P) and New Measurement of the h(b)(1P) and eta(b)(1S) Parameters
Using a sample of 771.6 x 10(6) Upsilon Upsilon(4S) decays collected by the Belle experiment at the KEKB e(+)e(-) collider, we observe, for the first time, the transition Upsilon(4S) -> eta h(b)(1P) with the branching fraction B[Upsilon(4S) -> eta h(b)(1P)] = (2.18 +/- 0.11 +/- 0.18) x 10(-3) and we measure the h(b)(1P) mass M-hb(1P) = (9899.3 +/- 0.4 +/- 1.0) MeV/c(2), corresponding to the hyperfine (HF) splitting Delta M-HF(1P) = (0.6 +/- 0.4 +/- 1.0) MeV/c(2). Using the transition h(b)(1P) -> gamma eta(b)(1S), we measure the eta(b)(1S) mass M-eta b(1S) = (9400.7 +/- 1.7 +/- 1.6) MeV/c(2), corresponding to Delta M-HF(1S) = (59.6 +/- 1.7 +/- 1.6) MeV/c(2), the eta(b)(1S) width Gamma(eta b)(1S) = (8(-5)(+6)+/- 5) MeV/c(2) and the branching fraction B[h(b)(1P) -> gamma eta(b)(1S)] = (56 +/- 8 +/- 4)%., 2015年09月, PHYSICAL REVIEW LETTERS, 115 (14), 142001, doi;web_of_science研究論文（学術雑誌）
Study of D** production and light hadronic states in the (B)over-bar(0) -> D*(+)omega pi(-) decay
We report on the first observations of (B) over bar (0) -> D-1 (2430)(0)omega, (B) over bar (0) -> D-1 (2420)(0)omega, and (B) over bar (0) -> D-2* (2460)(0)omega decays. The (B) over bar (0) -> D*(+) rho(1450)(-) decay is also observed. The branching fraction measurements are based on (771.6 +/- 10.6) x 10(6) B (B) over bar events collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The fractions of longitudinal polarization of the D** states as well as partial wave fractions of the D-1 (2430)(0) are obtained. We also set a 90% confidence level upper limit for the product of branching fractions of B((B) over bar (0) -> D*(+)b(1) (1235)(-)) x B(b(1) (1235)(-) -> omega pi(-)). The measurements show evidence of nontrivial final-state interaction phases for the rho-meson-like amplitudes., 2015年07月, PHYSICAL REVIEW D, 92 (1), 012013, doi;web_of_science研究論文（学術雑誌）
Measurements of B -> (D)over-barDs0*(+)(2317) decay rates and a search for isospin partners of the Ds0*(+)(2317)
We report improved measurements of the product branching fractions B(B+ --> (D) over bar D-0(s0)*(+)(2317)) x B(D-s0*(+)(2317) --> D-s(+) pi(0)) (8.0(-1.2)(+1.3) +/- 1.1 +/- 0.4) x 10(-4) and B(B-0 --> D-Ds0*(+)(2317)) x B(D-s0*(+)(2317)) --> D-s(+) pi(0)) = (10.2(-1.2)(+1.3) +/- 1.0 +/- 0.4) x 10(-4) where the first errors are statistical, the second are systematic and the third are from D and D-s(+) branching fractions. In addition, we report negative results from a search for hypothesized neutral (z(0)) and doubly charged (z(++)) isospin partners of the D-s0*(+)(2317) and provide upper limits on the product branching fractions B(B-0 --> D(0)z(0)) x B(z(0) --> D-s(+)pi(-)) and B(B+ --> D(0)z(++) ) x B(z(++) --> D-s(+)pi(+)) that are more than an order of magnitude smaller than theoretical expectations for the hypotheses that the D-s0(*+)(2317) is a member of an isospin triplet. The analysis uses a 711 fb(-1) data sample containing 772 million B (B) over bar -meson pairs collected at the Upsilon(4S) resonance in the Belle detector at the KEKB collider., 2015年05月, PHYSICAL REVIEW D, 91 (9), 092011, doi;web_of_science研究論文（学術雑誌）
Measurement of the direct CP asymmetry in B ¯ →xs+dγ decays with a lepton tag
© 2015 American Physical Society. We report the measurement of the direct CP asymmetry in the radiative B¯→Xs+dγ decay using a data sample of (772±11)×106 BB¯ pairs collected at the (4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. The CP asymmetry is measured as a function of the photon energy threshold. For Eγ∗≥2.1GeV, where Eγ∗ is the photon energy in the center-of-mass frame, we obtain ACP(B¯→Xs+dγ)=(2.2±3.9±0.9)%, consistent with the standard model prediction., 2015年04月, Physical Review Letters, 114 (15), doi;web_of_science;url研究論文（学術雑誌）
Amplitude analysis of e(+)e(-) -> Upsilon(nS)pi(+)pi(-) at root s=10.866 GeV
We report results on studies of the e(+)e(-) annihilation into three-body Upsilon(nS)pi(+)pi(-) (n = 1, 2, 3) final states including measurements of cross sections and the full amplitude analysis. The cross sections measured at root s = 10.866 GeV and corrected for the initial state radiation are sigma(e(+)e(-) --> Upsilon(1S)pi(+)pi(-)) = (2.27 +/- 0.12 +/- 0.14) pb, sigma(e(+)e(-) --> Upsilon(2S)pi(+)pi(-)) = (4.07 +/- 0.16 +/- 0.45) pb, and sigma(e(+)e(-) --> Upsilon(3S)pi(+)pi(-)) = (1.46 +/- 0.09 +/- 0.16) pb. Amplitude analysis of the three-body Upsilon(nS)pi(+)pi(-) final states strongly favors I-G(J(P)) = 1(+)(1(+)) quantum-number assignments for the two bottomonium-like Z(b)(+/-) states, recently observed in the Upsilon(nS)pi(+) and h(b)(mP)pi(+)(m = 1, 2) decay channels. The results are obtained with a 121.4 fb(-1) data sample collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider., 2015年04月, PHYSICAL REVIEW D, 91 (7), 072003, doi;web_of_science研究論文（学術雑誌）
Observation of X(3872) in B -> X(3872)K pi decays
We report the first observation of B-0 -> X(3872)(K+pi(-)) and evidence for B+ -> X(3872)(K-0 pi(+)). We measure the product of branching fractions for the former to be B(B-0 -> X(3872)(K+pi(-)) x B(X(3872) -> J/psi pi(+)pi(-)) = (7.9 +/- 1.3(stat) +/- 0.4(syst) x 10(-6) and find that B-0 -> X(3872)K*(892)(0) does not dominate the B-0 -> X(3872)K+pi(-) decay mode. We also measure B(B+ -> X(3872)(K-0 pi(+))) x B(X(3872) -> J/psi pi(+)pi(-)) = (10.6 +/- 3.0(stat) +/- 0.9(syst) x 10(-6). This study is based on the full data sample of 711 fb(-1) (772 x 10(6)B (B) over bar pairs) collected at the Upsilon(4S) resonance with the Belle detector at the KEKB collider., 2015年03月, PHYSICAL REVIEW D, 91 (5), 051101, doi;web_of_science研究論文（学術雑誌）
Measurement of time-dependent CP violation in B-0 - eta ' K-0 decays
We present a measurement of the time-dependent CP violation parameters in B0 -> eta'K-0 decays. The measurement is based on the full data sample containing 772 x 10(6) B (B) over bar pairs collected at the Upsilon(4S) resonance using the Belle detector at the KEKB asymmetric-energy e+e- collider. The measured values of the mixing-induced and direct CP violation parameters are: sin 2 phi(eff)(1) = +0.68 +/- 0.07 +/- 0.03, A(eta'K0) = +0.03 +/- 0.05 +/- 0.04, where the first uncertainty is statistical arid the second is systernatic. The values obtained are the most accurate to date. lurthierrimore. these results are consistent with our previous measurements and with the world-average value of sin 2 phi(1) measured in B-0 -> J/psi K-0 decays., 2014年10月, JOURNAL OF HIGH ENERGY PHYSICS, 1410 (10), 165, doi;web_of_science研究論文（学術雑誌）
Measurement of branching fractions and CP violation parameters in B -> omega K decays with first evidence of CP violation in B-0 -> omega K-s(0)
We present a measurement of the branching fractions and charge- parity-( CP-) violating parameters in B..K decays. The results are obtained from the final data sample containing 772 x 10(6) BB _ pairs collected at the.d4S_ resonance with the Belle detector at the KEKB asymmetric- energy e_e- collider. We obtain the branching fractions BdB0 0 _d4.5 0.4dstat_ 0.3dsyst_x10- 6; BdB_..K__ d6.80.4dstat_ 0.4dsyst__x10- 6 which are in agreement with their respective current world averages. For the CP- violating parameters, we obtain A.K0 S - 0.36 +/- 0.19dstat_ 0.05dsyst_; S.K0 S _0.91 0.32dstat_ 0.05dsyst_; A.K_ - 0.03 +/- 0.04dstat_ 0.01dsyst_; where A and S represent the direct and mixing- induced CP asymmetry, respectively. We find no evidence of CP violation in the decay channel B_..K_; however, we obtain the first evidence of CP violation in the B0..K0 S decay channel at the level of 3.1 standard deviations., 2014年07月, PHYSICAL REVIEW D, 90 (1), 012002, doi;web_of_science研究論文（学術雑誌）
Measurement of the Branching Fraction B(Lambda(+)(c) -> pK(-)pi(+))
We present the first model-independent measurement of the absolute branching fraction of the Lambda(+)(c) -> pK(-)pi(+)decay using a data sample of 978 fb(-1) collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The number of Lambda(+)(c) baryons is determined by reconstructing the recoiling D(*)(-)(p) over bar pi(+)system in events of the type e(+)e(-) -> D(*)(-)(p) over bar pi(+)Lambda(+)(c). The branching fraction is measured to be B(Lambda(+)(c) -> pK(-)pi(+)) = (6.84 +/- 0.24(-0.27)(+0.21))%, where the first and second uncertainties are statistical and systematic, respectively., 2014年07月, PHYSICAL REVIEW LETTERS, 113 (4), 042002, doi;web_of_science研究論文（学術雑誌）
Study of B-0 -> rho(0)rho(0) decays, implications for the CKM angle phi(2) and search for other B-0 decay modes with a four-pion final state
We present a study of the branching fraction of the decay B-0 -> rho(0)rho(0) and the fraction of longitudinally polarized rho(0) mesons in this decay. The results are obtained from the final data sample containing 772 x 10(6) B (B) over bar pairs collected at the gamma(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We find 166 +/- 59 B-0 -> rho(0)rho(0) events (including systematic uncertainties), corresponding to a branching fraction of B(B-0 -> rho(0)rho(0)) = (1.02 +/- 0.30(stat) +/- 0.15(syst)) x 10(-6) with a significance of 3.4 standard deviations and a longitudinal polarization fraction f(L) = 0.21(-0.22)(+0.18()stat) +/- 0.15(syst). We use the longitudinal polarization fraction to determine the Cabibbo-Kobayashi-Maskawa matrix angle phi(2) = (84.9 +/- 13.5)degrees through an isospin analysis in the B ->rho rho system. We furthermore find 125 +/- 41 B-0 -> f(0)rho(0) events, corresponding to B(B-0 -> f(0)rho(0)) x B(f(0) -> pi(+)pi(-)) = (0.78 +/- 0.22(stat) +/- 0.11(syst)) x 10(-6), with a significance of 3.1 standard deviations. We find no other significant contribution with the same final state, and set upper limits at 90% confidence level on the (product) branching fractions, B(B-0 -> pi(+)pi(-)pi(+)pi(-)) < 11.2 x 10(-6), B(B-0 -> rho(0)pi(+)pi(-)) < 12.0 x 10(-6), B(B-0 -> f(0)pi(+)pi(-)) x B(f(0) -> pi(+)pi(-)) < 3.0 x 10(-6) and B(B-0 -> f(0)f(0)) x B(f(0) -> pi(+)pi(-))(2) < 0.2 x 10(-6)., 2014年04月, PHYSICAL REVIEW D, 89 (7), 072008, doi;web_of_science研究論文（学術雑誌）
Measurement of branching fractions for B -> J/psi eta K decays and search for a narrow resonance in the J/psi eta final state
We report an observation of the B-+/- -> J/psi eta K-+/- and B-0 -> J/psi eta K-S(0) decays using 772 x 10(6)B (B) over bar pairs collected at the gamma (4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We obtain the branching fractions B(B-+/- -> J/psi eta K-+/-) = (1.27 +/- 0.11 (stat.) +/- 0.11 ( syst.)) x 10(- 4) and B(B-0 -> J/psi eta K-S(0)) = ( 5.22 +/- 0.78 (stat.) +/- 0.49 (syst.)) x 10(-5). We search for a new narrow charmonium(- like) state X in the J/psi eta mass spectrum and find no significant excess. We set upper limits on the product of branching fractions, B(B-+/- -> XK +/-) B(X -> J/psi eta), at 3872 MeV c(-2) where a C-odd partner of X(3872) may exist, psi(4040) and psi(4160) assuming their known mass and width, and over a range from 3.8 to 4.8 GeV c(-2). The obtained upper limits at 90% confidence level for XC-odd(3872), psi(4040), and psi(4160) are 3.8 x 10(-6), 15.5 x 10(-6), and 7.4 x 10(-6), respectively., 2014年04月, PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS, 043 (4), C01, doi;web_of_science研究論文（学術雑誌）
Search for doubly charmed baryons and study of charmed strange baryons at Belle
We report results of a study of doubly charmed baryons and charmed strange baryons. The analysis is performed using a 980 fb(-1) data sample collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We search for doubly charmed baryons Xi(+(+))(cc) with the Lambda(+)(c) K- pi(+)(pi(+) ) and. Xi(0)(c) pi(+)(pi(+)) final states. No significant signal is observed. We also search for two excited charmed strange baryons, Xi(c)(3055)(+) and Xi(c)(3123)(+) with the Sigma(++)(c)(2455)K- and Sigma(++)(c)(2520)K- final states. The Xi(c)(3055)(+) signal is observed with a significance of 6.6 standard deviations including systematic uncertainty, while no signature of the Xi(c)(3123)(+) is seen. We also study properties of the Xi(c)(2645)(+) and measure a width of 2.6 +/- 0.2(stat) +/- 0.4(syst) MeV/c(2), which is the first significant determination., 2014年03月, PHYSICAL REVIEW D, 89 (5), 052003, doi;web_of_science研究論文（学術雑誌）
Measurement of the CP violation parameters in B-0 -> pi(+) pi(-) decays
We present a measurement of the charge-parity (CP) violating parameters in B-0 -> pi(+) pi(-) decays. The results are obtained from the final data sample containing 772 x 10(6) B (B) over bar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+) e(-) collider. We obtain the CP violation parameters A(cp)(B-0 -> pi(+) pi(-)) = +0.33 +/- 0.06(stat) +/- 0.03(syst), S-cp(B-0 -> pi(+) pi(-)) = -0.64 +/- 0.08(stat) +/- 0.03(syst), where A(CP) and S-CP represent the direct and mixing-induced CP asymmetries in B-0 -> pi(+) pi(-) decays, respectively. Using an isospin analysis including results from other Belle measurements, we find 23.8 degrees < phi(2) < 66.8 degrees is disfavored at the 1 sigma level, where phi(2) is one of the three interior angles of the Cabibbo-Kobayashi-Maskawa unitarity triangle related to B-u,B-d decays., 2013年11月, PHYSICAL REVIEW D, 88 (9), 092003, doi;web_of_science研究論文（学術雑誌）
Experimental constraints on the spin and parity of the Z(4430)(+)
We perform a full amplitude analysis of B-0 -> psi'K+ pi(-) decays, with psi' -> mu + mu- or e+e -, to constrain the spin and parity of the Z(4430)-. The JP = 1(+) hypothesis is favored over the 0(-), 1(-), 2(-) and 2(+) hypotheses at the levels of 3: 4 sigma, 3: 7 sigma, 4: 7 sigma and 5.1 sigma , respectively. The analysis is based on a 711 fb(-1) data sample that contains 772 x 10(6) B (B) over bar pairs collected at the Upsilon(4S) resonance by the Belle detector at the asymmetric-energy e(+)e(-) collider KEKB., 2013年10月, PHYSICAL REVIEW D, 88 (7), 074026, doi;web_of_science研究論文（学術雑誌）
First observation of the Z(b)(0)(10610) in a Dalitz analysis of Upsilon(10860) -> Upsilon(nS)pi(0)pi(0)
We report the first observation of Upsilon(10860) -> Upsilon(1, 2, 3S)pi(0)pi(0) decays. The neutral partner of the Z(1/b)(10610), the Z(b)(0)(10610) decaying to Upsilon(2, 3S)pi(0), is observed for the first time with a 6.5 sigma significance using a Dalitz analysis of Upsilon(10860) -> Upsilon (2, 3S)pi(0)pi(0) decays. The results are obtained with a 121.4 fb(-1) data sample collected with the Belle detector at the Upsilon(10860) resonance at the KEKB asymmetric- energy e(+)e(-) collider., 2013年09月, PHYSICAL REVIEW D, 88 (5), 052016, doi;web_of_science研究論文（学術雑誌）
Evidence of a new narrow resonance decaying to χ
We report measurements of B→χc1γK and χc2γK decays using 772×106 BB̄ events collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. Evidence of a new resonance in the χc1γ final state is found with a statistical significance of 3.8σ. This state has a mass of 3823.1±1.8(stat)±0.7(syst) MeV/c2, a value that is consistent with theoretical expectations for the previously unseen 1D23 cc̄ meson. We find no other narrow resonance and set upper limits on the branching fractions of the X(3872)→χc1γ and χc2γ decays. © 2013 American Physical Society., 2013年07月16日, Physical Review Letters, 111 (3), 032001, doi;scopus;scopus_citedbyc1 γ in B→χc1 γK研究論文（学術雑誌）
Study of e(+)e(-) -> pi(+)pi(-) J/psi and Observation of a Charged Charmoniumlike State at Belle
The cross section for e(+)e(-) -> pi(+)pi(-) J/psi between 3.8 and 5.5 GeV is measured with a 967 fb(-1) data sample collected by the Belle detector at or near the Upsilon(nS) (n = 1, 2, . . . , 5) resonances. The Y(4260) state is observed, and its resonance parameters are determined. In addition, an excess of pi(+)pi(-) J/psi production around 4 GeV is observed. This feature can be described by a Breit-Wigner parametrization with properties that are consistent with the Y(4008) state that was previously reported by Belle. In a study of Y(4260) -> pi(+)pi(-) J/psi decays, a structure is observed in the M(pi(+/-) J/psi) mass spectrum with 5.2 sigma significance, with mass M = (3894.5 +/- 6.6 +/- 4.5) MeV/c(2) and width Gamma = (63 +/- 24 +/- 26) MeV/c(2), where the errors are statistical and systematic, respectively. This structure can be interpreted as a new charged charmoniumlike state., 2013年06月, PHYSICAL REVIEW LETTERS, 110 (25), 252002, doi;web_of_science研究論文（学術雑誌）
Evidence for the η
We report the first evidence for the ηb(2S) using the h b(2P)→ηb(2S)γ transition and the first observation of the hb(1P)→ηb(1S)γ and hb(2P)→ηb(1S)γ transitions. The mass and width of the ηb(1S) and ηb(2S) are measured to be mηb (1S)=(9402.4±1.5±1.8) MeV/c2, m ηb (2S)=(9999.0±3.5-1.9+2.8) MeV/c2, and Γηb (1S)=(10.8-3.7-2.0+4.0+4.5) MeV. We also update the hb(1P) and hb(2P) mass measurements. We use a 133.4 fb-1 data sample collected at energies near the γ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+e - collider. © 2012 American Physical Society., 2012年12月, Physical Review Letters, 109 (23), doi;web_of_science;urlb (2S) and observation of hb (1P)→ηb (1S)γ and hb (2P) →ηb (1S)γ研究論文（学術雑誌）
Measurement of gamma gamma* -> pi(0) transition form factor at Belle
We report a measurement of the process gamma gamma* -> pi(0) with a 759 fb(-1) data sample recorded with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The pion transition form factor, F(Q(2)), is measured for the kinematical region 4 GeV2 <= Q(2) <= 40 GeV2, where -Q(2) is the invariant-mass squared of a virtual photon. The measured values of Q(2)vertical bar F(Q(2))vertical bar agree well with the previous measurements below Q(2) similar or equal to 9 GeV2 but do not exhibit the rapid growth in the higher Q(2) region seen in another recent measurement, which exceeds the asymptotic QCD expectation by as much as 50%., 2012年11月, PHYSICAL REVIEW D, 86 (9), 092007, doi;web_of_science研究論文（学術雑誌）
TIME-DEPENDENT CP VIOLATION AND MIXING AT B FACTORIES
In the last decade, two B-factory experiments, BaBar and Belle performed a large number of measurements related to time-dependent CP violation and B-(B) over bar (0) mixing. Achievements of those measurements are reviewed and possible room for New Physics is discussed., 2012年07月, ACTA PHYSICA POLONICA B, 43 (7), 1553 - 1560, doi;web_of_science研究論文（学術雑誌）
Search for the decay B-0 -> DK*(0) followed by D -> K- pi(+)
We report a study of the decay B-0 -> DK+ pi(-) followed by D -> K- pi(+) , where D indicates D-0 or (D) over bar (0). We reconstruct the DK+ pi(-) state in a phase space corresponding to DK*(892)(0). The CP-violating angle phi(3) affects its decay rate via the interference between b -> u and b -> c transitions. The result is obtained from a 711 fb(-1) data sample that contains 772 X 10(6)B (B) over bar pairs collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+) e(-) collider. We measure the ratio R-DK*0 Gamma(B-0 -> [K- pi(+) ](D)K+ pi(-))/Gamma(B-0 -> [K+ pi(-)](D)K+ pi(-)) to be (4.5(-5.0-1.8)(+5.6+2.8)) X 10(-2), and set an upper limit of R-DK*0 < 0.16 at the 95% credible interval., 2012年07月, PHYSICAL REVIEW D, 86 (1), 011101, doi;web_of_science研究論文（学術雑誌）
First measurement of phi(3) with a model-independent Dalitz plot analysis of B-+/- -> DK +/-, D -> K-S(0)pi(+)pi(-) decay
We present the first measurement of the angle phi(3) of the unitarity triangle using a model-independent Dalitz plot analysis of B-+/- -> DK +/-, D -> K-S(0)pi(+)pi(-) ecays. The method uses, as input, measurements of the strong phase of the D -> K-S(0)pi(+)pi(-) amplitude from the CLEO Collaboration. The result is based on the full data set of 772 x 10(6) B (B) over bar pairs collected by the Belle experiment at the Gamma(4S) resonance. We obtain phi(3) = (77.3(-14.9)(+15.1) +/- 4.1 +/- 4.3)degrees and the suppressed amplitude ratio r(B) = 0.145 +/- 0.030 +/- 0.010 +/- 0.011. Here the first error is statistical, the second is the experimental systematic uncertainty, and the third is the error due to the precision of the strong-phase parameters obtained by CLEO., 2012年06月, PHYSICAL REVIEW D, 85 (11), 112014, doi;web_of_science研究論文（学術雑誌）
Measurements of branching fractions and time-dependent CP violating asymmetries in B-0 -> D-(*D-)+/-(-/+) decays
We report measurements of branching fractions and time-dependent CP asymmetries in B-0 -> D+D- and B-0 -> D*D-+/-(-/+) decays using a data sample that contains (772 +/- 11) x 10(6)B (B) over bar pairs collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We determine the branching fractions to be B(B-0 -> D+D-) = (2.12 +/- 0.16 +/- 0.18) X 10(-4) and B(B-0 -> D*D-+/-(-/+)) = (6.14 +/- 0.29 +/- 0.50) x 10(-4). We measure CP asymmetry parameters SD+D- = -1.06(-0.14)(+0.21) +/- 0.08 and CD+D- = -0.43 +/- 0.16 +/- 0.05 in B-0 -> D+D- and A(D*D) = +0.06 +/- 0.05 +/- 0.02, S-D*D = -0.78 +/- 0.15 +/- 0.05, C-D*D = -0.01 +/- 0.11 +/- 0.04, +/- Delta S-D*D = -0.13 +/- 0.15 +/- 0.04 and Delta C-D*D = +0.12 +/- 0.11 +/- 0.03 in B-0 -> D*D-+/-(-/+), where the first uncertainty is statistical and the second is systematic. We exclude the conservation of CP symmetry in both decays at equal to or greater than 4 sigma significance., 2012年05月, PHYSICAL REVIEW D, 85 (9), 091106, doi;web_of_science研究論文（学術雑誌）
Search for Time-Dependent CPT Violation in Hadronic and Semileptonic B Decays
We report a new sensitive search for C P T violation, which includes improved measurements of the C P T-violating parameter z and the total decay-width difference normalized to the averaged width delta(d) delta(d) of the two B-d mass eigenstates . The results are based on a data sample of 535 x 10(6) B B pairs collected at the Epsilon(4 S) resonance with the Belle detector at the KEKB asymmetric-energy e(+) e(-) collider. We obtain Re (z) = [+1.9 +/- 3.7 (stat) +/- 3.3 (syst)] x 10(>-2), qm (z) = [-5.7 +/- 3.3 (stat) +/- 3.3 (syst)] x 10(-3), and delta(d) / delta(d) = [-1.7 +/- 1.8 (stat) +/- 1.1 (syst)] x 10(-2), all of which are consistent with zero. This is the most precise single measurement of these parameters in the neutral B-meson system to date., 2012年04月, PHYSICAL REVIEW D, 85 (7), 091102, doi;web_of_science研究論文（学術雑誌）
Precise Measurement of the CP Violation Parameter sin2 phi(1) in B-0 -> (c(c)over-bar)K-0 Decays
We present a precise measurement of the CP violation parameter sin2 phi(1) and the direct CP violation parameter A(f) using the final data sample of 772 x 10(6) B (B) over bar pairs collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson is reconstructed in a J / psi K-S(0), psi (2S)K-S(0), chi K-c1(S)0, or J / psi K-L(0) CP eigenstate and its flavor is identified from the decay products of the accompanying B meson. From the distribution of proper-time intervals between the two B decays, we obtain the following CP violation parameters: sin2 phi(1) = 0.667 +/- 0.023(stat) +/- 0.012(syst) and A(f) = 0.006 +/- 0.016(stat) +/- 0.012(syst)., 2012年04月, PHYSICAL REVIEW LETTERS, 108 (17), 171802, doi;web_of_science研究論文（学術雑誌）
Physics achievements from the Belle experiment
The Belle experiment, running at the KEKB e(+)e(-) asymmetric energy collider during the first decade of the century, achieved its original objective of precisely measuring differences between particles and antiparticles in the B system. After collecting 1000 fb(-1) of data at various Upsilon resonances, Belle also obtained the many other physics results described in this article., 2012年, PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS, (1), doi;web_of_science;url研究論文（学術雑誌）
Study of B-+/- -> K-+/-(KSK pi)(0) decay and determination of eta(c) and eta(c)(2S) parameters
We report the results of a study of B KIrk and /II K tic(2S) decays followed by qc and '/c(2S) decays to (K5K7). The results are obtained from a data sample containing 535 million BB-meson pairs collected by the Belle experiment at the KEKB e+e- collider. We measure the products of the branching fractions B(B > IC7ic)13(71, Ks K 7T) = (26.7 1.4(stat)+N(syst) 4.9(model)) x 10-6 and 8(B -+ K 71c(25))8(rIc(2S) Ksi(7tT) = (3.4+N(stat + model)t(syst)) x 10-6. Interference with the non-resonant component leads to significant model uncertainty in the measurement of these product branching fractions. Our analysis accounts for this interference and allows the model uncertainty to be reduced. We also obtain the following charmonia masses and widths: MO/c) = (2985.4 1.5(stat)1:8(syst)) MeV /c2, r(t1c)= (35.1 3.1(sta0+1:2(syst)) MeV/c2, M(ric (2S)) = (3636.111(stat + model)+3:70 (syst)) MeV/c2, r (17c (2S)) = (6.61:1(stat + model)11(syst)) MeV/c2. C) 2011 Elsevier B.V. All rights reserved., 2011年12月, PHYSICS LETTERS B, 706 (2-3), 139 - 149, doi;web_of_science研究論文（学術雑誌）
Bounds on the width, mass difference and other properties of X(3872) -> pi(+)pi(-) J/psi decays
We present results from a study of X(3872) -> pi pi J/psi decays produced via exclusive B -> KX(3872) decays. We determine the mass to be M-X(3872) = (3871.85 +/- 0.27(stat) +/- 0.19(syst)) MeV, a 90% confidence level upper limit on the natural width of Gamma(X(3872)) < 1.2 MeV, the product branching fraction B(B+ -> K+X(3872)) X B(X(3872) -> pi(+)pi(-) J/psi) = (8.63 +/- 0.82(stat) +/- 0.52(syst)) X 10(-6), and a ratio of branching fractions B(B-0 -> (KX)-X-0(3872))/B(B+ -> K+X(3872)) = 0.50 +/- 0.14(stat)) +/- 0.04(syst). The difference in mass between the X(3872) -> pi(+)pi(-) J/psi signals in B+ and B-0 decays is Delta M-X(3872) = (-0.71 +/- 0.96(stat) +/- 0.19(syst)) MeV. A search for a charged partner of the X(3872) in the decays <(B)over bar>(0) -> K-X+ or B+ -> (KX+)-X-0, X+ -> pi(+)pi(0) J/psi resulted in upper limits on the product branching fractions for these processes that are well below expectations for the case that the X(3872) is the neutral member of an isospin triplet. In addition, we examine possible J(PC) quantum number assignments for the X(3872) based on comparisons of angular correlations between final state particles in X(3872) -> pi(+)pi(-) J/psi decays with simulated data for J(PC) values of 1(++) and 2(-+). We examine the influence of rho-omega interference in the M(pi(+)pi(-)) spectrum. The analysis is based on a 711 fb(-1) data sample that contains 772 x 10(6) B (B) over bar meson pairs collected at the gamma(4S) resonance in the Belle detector at the KEKB e(+)e(-) collider., 2011年09月, PHYSICAL REVIEW D, 84 (5), 052004, doi;web_of_science研究論文（学術雑誌）
Search for CP Violation in tau(+/-) -> K-S(0)pi(+/-)nu(tau) Decays at Belle
We report on a search for CP violation in tau(+/-) -> K-S(0)pi(+/-)nu(tau) decays using a data sample of 699 fb(-1) collected by the Belle experiment at the KEKB electron-positron asymmetric-energy collider. The CP asymmetry is measured in four bins of the invariant mass of the K-S(0)pi(+/-) system and found to be compatible with zero with a precision of O(10(-3)) in each mass bin. Limits for the CP violation parameter Im(eta(S)) are given at the 90% confidence level. These limits are |Im(eta(S))| < 0.026 or better, depending on the parametrization used to describe the hadronic form factors, and improve upon previous limits by 1 order of magnitude., 2011年09月, PHYSICAL REVIEW LETTERS, 107 (13), 131801, doi;web_of_science研究論文（学術雑誌）
Observation of X(3872) -> J/psi gamma and Search for X(3872) -> psi 'gamma in B Decays
We report a study of B -> (J/psi gamma)K and B -> (psi'gamma)K decay modes using 772 X 10(6) B (B) over bar events collected at the Y(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. We observe X(3872) -> J/psi gamma and report the first evidence for chi(c2) -> J/psi gamma in B -> (X-c (c) over bar gamma)K decays, while in a search for X(3872) -> psi'gamma no significant signal is found. We measure the branching fractions, B(B-+/- -> X(3872)K-+/-)B(X(3872) -> J/psi gamma) = (1.78(-0.44)(+0.48) +/- 0.12) X 10(-6), B(B-+/- -> chi K-c2(+/-)) = (1.11(-0.34)(+0.36) +/- 0.09) X 10(-5), B(B+ -> X(3872)K+)B(X(3872) -> psi'gamma) < 3.45 X 10(-6) (upper limit at 90% C. L.), and also provide upper limits for other searches., 2011年08月, PHYSICAL REVIEW LETTERS, 107 (9), 091803, doi;web_of_science研究論文（学術雑誌）
Evidence for the Suppressed Decay B- -> DK-, D -> K+pi-
The suppressed decay chain B- -> DK-, D -> K+pi(-), where D indicates a (D) over bar (0) or D-0 state, provides important information on the CP-violating angle phi(3). We measure the ratio R-DK of the decay rates to the favored mode B- -> DK-, D -> K+pi(-) to be R-DK = [1.63(-0.41)(+0.44)(stat)(-0.13)(+0.07)(syst)] x 10(-2), which indicates the first evidence of the signal with a significance of 4.1 sigma. We also measure the asymmetry A(DK) between the charge-conjugate decays to be A(DK) = -0.39(-0.28)(+0.26)(stat)(-0.03)(+0.04)(syst). The results are based on the full 772 x 10(6) B (B) over bar pair data sample collected at the Gamma(4S) resonance with the Belle detector., 2011年06月, PHYSICAL REVIEW LETTERS, 106 (23), 231802, doi;web_of_science研究論文（学術雑誌）
Study of the K+ pi(+) pi(-) final state in B+ -> J/psi K+ pi(+) pi(-) and B+ -> psi ' K+ pi(+) pi(-)
Using 535 X 10(6) B-meson pairs collected by the Belle detector at the KEKB e(+)e(-) collider, we measure branching fractions of (7.16 +/- 0.10(stat) +/- 0.60(syst) X 10(-4) for B+ -> J/psi K+ pi(+) pi(-) and (4.31 +/- 0.20(stat) +/- 0.50(syst)) X 10(-4) for B+ -> psi' K+ pi(+) pi(-). We perform amplitude analyses to determine the resonant structure of the K+ pi(+) pi(-) final state in B+ -> J/psi K+ pi(+) pi(-) and B+ -> psi' K+ pi(+) pi(-) and find that the K-1(1270) is a prominent component of both decay modes. There is significant interference among the different intermediate states, which leads, in particular, to a striking distortion of the rho line shape due to the omega. Based on the results of the fit to the B+ -> J/psi K+ pi(+) pi(-) data, the relative decay fractions of the K-1(1270) to K rho, K omega, and K*(892)pi are consistent with previous measurements, but the decay fraction to K-0(*)(1430) is significantly smaller. Finally, by floating the mass and width of the K-1(1270) in an additional fit of the B+ -> J/psi K+ pi(+) pi(-) data, we measure a mass of (1248.1 +/- 3.3(stat) +/- 1.4(syst)) MeV/c(2) and a width of (119.5 +/- 5.2(stat) +/- 6.7(syst)) MeV/c(2) for the K-1(1270)., 2011年02月, PHYSICAL REVIEW D, 83 (3), 032005, doi;web_of_science研究論文（学術雑誌）
Search for CP-violating charge asymmetry in B-+/- -> J/psi K-+/- decays
We present the result of a search for charge asymmetry in B-+/- -> J/psi K-+/- decays using 772 X 10(6) B (B) over bar pairs collected at the Y(4S) resonance by the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The CP-violating charge asymmetry is measured to be A(CP)(B+ -> J/psi K+) = [-0.76 +/- 0.50 (stat) +/- 0.22 (syst)]%., 2010年11月, PHYSICAL REVIEW D, 82 (9), 091104, doi;web_of_science研究論文（学術雑誌）
Measurements of branching fractions for B-0 -> D-s(+) pi(-) and (B)over-bar(0) -> D-s(+) K-
We present improved measurements of the branching fractions for the decays B-0 -> D-s(+) pi(-) and (B) over bar (0) -> D-s(+) K- using a data sample of 657 X 10(6) B (B) over bar events collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric- energy e(+)e(-) collider. The results are B(B-0 -> D-s(+) pi(-)) = (1.99 +/- 0.26 +/- 0.18) X 10(-5) and B((B) over bar (0) -> D-s(+) K-) = (1.91 +/- 0.24 +/- 0.17) X 10(-5), where the uncertainties are statistical and systematic, respectively. Based on these results, we determine the ratio between amplitudes of the doubly Cabibbo suppressed decay B-0 -> D+pi(-) and the Cabibbo favored decay B-0 -> D-pi(+), R-D pi = [1.71 +/- 0.11(stat) +/- 0.09(syst) +/- 0.02(theo)]%, where the last term denotes the theory error., 2010年09月, PHYSICAL REVIEW D, 82 (5), 051103, doi;web_of_science研究論文（学術雑誌）
Evidence for direct CP violation in the decay B-+/- -> D-(*()) K-+/-, D -> K-S(0)pi(+)pi(-) and measurement of the CKM phase phi(3)
We present a new measurement of the unitarity triangle angle phi(3) using a Dalitz plot analysis of the K-S(0)pi(+)pi(-) decay of the neutral D meson produced in B-+/- -> D-(*()) K-+/- decays. The method exploits the interference between D-0 and (D) over bar (0) to extract the angle phi(3), strong phase delta, and the ratio r of suppressed and allowed amplitudes. We apply this method to a 605 fb(-1) data sample collected by the Belle experiment. The analysis uses three decays: B-+/- -> DK +/-, and B-+/- -> D*K-+/- with D* -> D pi(0) and D* -> D gamma, as well as the corresponding charge-conjugate modes. From a combined maximum likelihood fit to the three modes, we obtain phi(3) = 78.4 degrees (+10.8 degrees)(-11.6 degrees) +/- 3.6 degrees (syst) +/- 8.9 degrees (model). CP conservation in this process is ruled out at the confidence level (1 - CL) = 5 X 10(-4), or 3.5 standard deviations., 2010年06月, PHYSICAL REVIEW D, 81 (11), 112002, doi;web_of_science研究論文（学術雑誌）
Measurement of the branching fractions for B-0 -> Ds(*+)pi(-) and B-0 -> Ds*-K+ decays
We present a study of B-0 -> D-s*(+)pi(-) and B-0 -> D-s*K--(+) decays based on a sample of 657 x 10(6) B (B) over bar events collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We measure the branching fractions to be B(B-0 -> D-s*(+)pi(-)) = (1.75 +/- 0.34(stat) +/- 0.17(syst) +/- 0.11(B)) x 10(-5) and B(B-0 -> D-s*K--(+)) = (2.02 +/- 0.33(stat) +/- 0.18(syst) +/- 0.13(B)) x 10(-5), with significances of 6.1 and 8.0 standard deviations, respectively. The first uncertainty is statistical, the second is due to the experimental systematics, and the third is from uncertainties in the D-s(+) decay branching fractions. From our measurements, we obtain the most precise determination so far of R-D*pi, where R-D*pi is the ratio between amplitudes of the doubly Cabibbo-suppressed decay B-0 -> D*(+)pi(-) and the Cabibbo-favored B-0 -> D*(-)pi(+) decay., 2010年02月, PHYSICAL REVIEW D, 81 (3), 031101, doi;web_of_science研究論文（学術雑誌）
Study of the B -> X(3872)(-> D*(0)(D)over-bar(0)K decay
We present a study of B -> X(3872)K with X(3872) decaying to D*(0)(D) over bar (0) using a sample of 657 x 10(6) B (B) over bar pairs recorded at the Gamma(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. Both D*(0) -> D-0 gamma and D*(0) -> D-0 pi(0) decay modes are used. We find a peak of 50.1(-11.1)(+14.8) events with a mass of (3872.9(-0.4-0.5)(+0.6+0.4)) MeV/c(2), a width of d 3.9(-1.4-1.1)(+2.8+0.2)) MeV/c(2) and a product branching fraction B(B -> X(3872)K) X B(X(3872) -> D*(0)(D) over bar (0)) = (0.80 +/- 0.20 +/- 0.10) X 10(-4), where the first errors are statistical and the second ones are systematic. The significance of the signal is 6.4 sigma. The difference between the fitted mass and the D*(0)(D) over bar (0) threshold is calculated to be (1.1(-0.4-0.3)(+0.6+0.1)) MeV/c(2). We also obtain an upper limit on the product of branching fractions B(B -> Y(3940)K) X B(Y(3940) -> D*(0)(D) over bar (0) of 0.67 X 10(-4) at 90% CL., 2010年02月, PHYSICAL REVIEW D, 81 (3), 031103, doi;web_of_science研究論文（学術雑誌）
Observation of an enhancement in e+e- to Upsilon(1S)pi+pi-, Upsilon(2S)pi+pi-, and Upsilon(3S)pi+pi- production around sqrt{s}=10.89 GeV at Belle
2010年, Phys. Rev., D (82), 091106Measurement of CP asymmetries in B-0 -> K-0 pi(0) decays
We report measurements of CP violation parameters in B-0 -> K-0 pi(0) decays based on a data sample of 657 X 10(6)B (B) over bar pairs collected with the Belle detector at the KEKB e(+)e(-) asymmetric-energy collider. We use B-0 -> K-S(0)pi(0) decays for both mixing-induced and direct CP violating asymmetry measurements and B-0 -> K-L(0)pi(0) decays for the direct CP violation measurement. The CP violation parameters obtained are sin2 phi(eff)(1) - +0.67 +/- 0.31(stat) +/- 0.08(syst) and A(K0 pi 0) - +0.14 +/- 0.13(stat) +/- 0.06(syst). The branching fraction of B-0 -> K-0 pi(0) decay is measured to be B(B-0 -> K-0 pi(0)) - (8.7 +/- 0.5(stat) +/- 0.6(syst)) X 10(-6). The observed A(K0 pi 0) value differs by 1.9 standard deviations from the value expected from an isospin sum rule., 2010年01月, PHYSICAL REVIEW D, 81 (1), 011101, doi;web_of_science研究論文（学術雑誌）
Time-dependent Dalitz plot measurement of CP parameters in B-0 -> K-S(0)pi(+)pi(-) decays
We present a time-dependent Dalitz plot measurement of CP violation parameters in B-0 -> K-S(0)pi(+)pi(-) decays. These results are obtained from a large data sample that contains 657x10(6) B(B)over bar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. For the CP violation parameters, we obtain two consistent solutions that describe the data well. The first of these solutions may be preferred by external information from other measurements. There is no evidence for direct CP violation in B-0 ->rho(0)(770)K-S(0), B-0 -> f(0)(980)K-S(0) and B-0 -> K*+(892)pi(-), while measurements of mixing-induced CP violation in B-0 ->rho(0)(770)K-S(0) and B-0 -> f(0)(980)K-S(0) decays are consistent with that of b -> c(c)over bars decays. We also measured the phase difference between B-0 -> K*+(892)pi(-) and (B)over bar(0)-> K*-(892)pi(+), which may be used to extract phi(3)., 2009年04月, PHYSICAL REVIEW D, 79 (7), 052006, doi;web_of_science研究論文（学術雑誌）
Evidence for B-0 -> chi(c1)pi(0) at Belle
We present a measurement of the branching fraction for the Cabibbo- and color-suppressed B-0 -> chi(c1)pi(0) decay based on a data sample of 657 x 10(6) B (B) over bar events collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We observe a signal of 40 +/- 9 events with a significance of 4.7 sigma including systematic uncertainties. The measured branching fraction is B(B-0 -> chi(c1)pi(0)) = (1.12 +/- 0.25 (stat) +/- 0.12(syst.)) x 10(-5)., 2008年11月, PHYSICAL REVIEW D, 78 (9), 091104, doi;web_of_science研究論文（学術雑誌）
Observation of two resonancelike structures in the pi(+)chi(c1) mass distribution in exclusive (B)overbar(0)-> K-pi(+)chi(c1) decays
We report the first observation of two resonancelike structures in the pi(+)chi(c1) invariant mass distribution near 4.1 GeV/c(2) in exclusive (B)overbar(0)-> K-pi(+)chi(c1) decays. From a Dalitz plot analysis in which the pi(+)chi(c1) mass structures are represented by Breit-Wigner resonance amplitudes, we determine masses and widths of: M-1=(4051 +/- 14(-41)(+20)) MeV/c(2), Gamma(1)=(82(-17-22)(+21+47)) MeV, M-2=(4248(-29-35)(+44+180)) MeV/c(2), and Gamma(2)=(177(-39-61)(+54+316)) MeV; and product branching fractions of B((B)overbar(0)-> K(-)Z(1,2)(+))xB(Z(1,2)(+)->pi(+)chi(c1))=(3.0(-0.8-1.6)(+1.5+3.7))x10(-5) and (4.0(-0.9-0.5)(+2.3+19.7))x10(-5), respectively. Here the first uncertainty is statistical, the second is systematic. The significance of each of the pi(+)chi(c1) structures exceeds 5 sigma, including the systematic uncertainty from various fit models. This analysis is based on 657x10(6) B(B)overbar events collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider., 2008年10月, PHYSICAL REVIEW D, 78 (7), 072004, doi;web_of_science研究論文（学術雑誌）
Observation of B-+/-->psi(2S)pi(+/-) and search for direct CP violation
We report the first observation of B-+/- -> psi(2S)pi(+/-), a Cabibbo- and color-suppressed decay. This analysis is based on 657 x 10(6) B (B) over bar B events collected at the Y(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. The measured branching fraction is (2.44 +/- 0.22 +/- 0.20) x 10(-5) and the charge asymmetry is A = 0.022 +/- 0.085 +/- 0.016. The ratio of the branching fractions B(B-+/- -> psi(2S)pi(+/-))/B(B-+/- -> psi(2S)K-+/-) = (3.99 +/- 0.36 +/- 0.17)% is also determined., 2008年09月, PHYSICAL REVIEW D, 78 (5), 051104, doi;web_of_science研究論文（学術雑誌）
1G2-C2 素粒子実験Belleを題材とした高校生向けサイエンスキャンプの実践報告(科学教育各論(1),一般研究発表,転換期の科学教育:これからの科学的リテラシー)
日本科学教育学会, 2008年08月08日, 年会論文集, 32, 205 - 206, cinii_articlesMeasurements of time-dependent CP violation in B(0) -> (2S)K(S)(0) decays
We report improved measurements of time-dependent CP violation parameters for B(0)((B) over bar (0))-> psi(2S)K(S)(0). This analysis is based on a data sample of 657 x 10(6) B (B) over bar pairs collected at the Gamma(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. We fully reconstruct one neutral B meson in the psi(2S)K(S)(0) CP-eigenstate decay channel, and the flavor of the accompanying B meson is identified to be either B(0) or (B) over bar (0) from its decay products. CP violation parameters are obtained from the asymmetries in the distributions of the proper-time intervals between the two B decays S(psi(2S)KS)(0) = + 0.72 +/- 0.09 (stat) +/- 0.03 (syst), A(psi(2S)KS)(0) = + 0.04 +/- 0.07 (stat) +/- 0.05 (syst). These results are in agreement with results from measurements of B(0)-> J/psi K(0)., 2008年05月, PHYSICAL REVIEW D, 77 (9), 091103, doi;web_of_science研究論文（学術雑誌）
Improved measurement of time-dependent CP violation in B0→J/ψπ0 decays
We report improved measurements of time-dependent CP violation parameters for B0(B̄0)→J/ψπ0 decay. This analysis is based on 535×106 BB̄ pairs accumulated at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. From the distribution of proper time intervals between the two B decays, we obtain the following CP violation parameters SJ/ψπ0=-0.65±0.21(stat) ±0.05(syst)andAJ/ψπ0=+0.08±0.16(stat)±0.05(syst), which are consistent with standard model expectations. © 2008 The American Physical Society., 2008年04月01日, Physical Review D - Particles, Fields, Gravitation and Cosmology, 77 (7), doi;url研究論文（学術雑誌）
Improved measurement of time-dependent CP violation in B-0 -> J/psi pi(0) decays
We report improved measurements of time-dependent CP violation parameters for B-0((B) over bar (0))-> J/psi pi(0) decay. This analysis is based on 535x10(6) B (B) over bar pairs accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. From the distribution of proper time intervals between the two B decays, we obtain the following CP violation parameters S-J/psi pi(0)=-0.65 +/- 0.21(stat)+/- 0.05(syst) and A(J/psi pi)(0)=+0.08 +/- 0.16(stat)+/- 0.05(syst),which are consistent with standard model expectations., 2008年04月, PHYSICAL REVIEW D, 77 (7), 071101, doi;web_of_science研究論文（学術雑誌）
Observation of a resonancelike structure in the pi(+-)psi ' mass distribution in exclusive B -> K pi(+-)psi ' decays
A distinct peak is observed in the pi(+/-)psi' invariant mass distribution near 4.43 GeV in B -> K pi(+/-)psi' decays. A fit using a Breit-Wigner resonance shape yields a peak mass and width of M=4433 +/- 4(stat)+/- 2(syst) MeV and Gamma=45(-13)(+18)(stat)(-13)(+30)(syst) MeV. The product branching fraction is determined to be B(B(0)-> K(-/+)Z(+/-)(4430))xB(Z(+/-)(4430)->pi(+/-)psi')=(4.1 +/- 1.0(stat)+/- 1.4(syst))x10(-5), where Z(+/-)(4430) is used to denote the observed structure. The statistical significance of the observed peak is 6.5 sigma. These results are obtained from a 605 fb(-1) data sample that contains 657x10(6) B (B) over bar pairs collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e(+)e(-) collider., 2008年04月, PHYSICAL REVIEW LETTERS, 100 (14), 142001, doi;web_of_science研究論文（学術雑誌）
Difference in direct charge-parity violation between charged and neutral B meson decays
Equal amounts of matter and antimatter are predicted to have been produced in the Big Bang, but our observable Universe is clearly matter- dominated. One of the prerequisites(1) for understanding this elimination of antimatter is the nonconservation of charge- parity ( CP) symmetry. So far, two types of CP violation have been observed in the neutral K meson ( K-0) and B meson ( B-0) systems: CP violation involving the mixing(2) between K-0 and its antiparticle (K) over bar (0) ( and likewise(3,4) for B-0 and (B) over bar (0)), and direct CP violation in the decay of each meson(5-8). The observed effects for both types of CP violation are substantially larger for the B-0 meson system. However, they are still consistent with the standard model of particle physics, which has a unique source(9) of CP violation that is known to be too small(10) to account for the matter-dominated Universe. Here we report that the direct CP violation in charged B-+/- --> K-+/- pi(0) decay is different from that in the neutral B-0 counterpart. The direct CP- violating decay rate asymmetry, A(K)+/- (pi 0) ( that is, the difference between the number of observed B- --> K- pi(0) event versus B+ --> K+ pi(0) events, normalized to the sum of these events) is measured to be about +7%, with an uncertainty that is reduced by a factor of 1.7 from a previous measurement(7). However, the asymmetry A(K+/-) p(-/+) for B-0 --> K- pi(+) versus B-0 --> K+ pi(-) is at the -10% level(7,8). Although it is susceptible to strong interaction effects that need further clarification, this large deviation in direct CP violation between charged and neutral B meson decays could be an indication of new sources of CP violation - which would help to explain the dominance of matter in the Universe., 2008年03月, NATURE, 452 (7185), 332 - U3, doi;web_of_science;url研究論文（学術雑誌）
B -> Charmonium(-like) decays at Belle
The recent Belle results for the B decays into the final states having a J/psi are reported. Search for B -> J/psi eta' K is performed and no significant signal is observed. The upper limits of the branching fractions are obtained to be B(B-+/- -> J/psi eta' K-+/-) < 8.8 x 10(-5) and B(B-0 -> J/psi eta' K-S(0)) < 2.5 x 10(-5) at 90 % C.L. The B-0 -> J/psi eta decay is observed with 8.1 sigma statistical significance, the branching fraction is obtained to be B(B-0 -> J/psi eta) = (9.5 +/- 1.7 +/- 0.8) x 10(-5). The study on B-0 -> J/psi pi(+)pi(-)decays are performed and rho(0) meson is found to be the dominant source of the di-pion. The obtained branching fractions are B(B-0 -> J/psi pi(+)pi(-)) = (2.4 +/- 0.3 +/- 0.2) x 10(-5) and B(B-0 -> J/psi rho(0)) = (2.0 +/- 0.2 +/- 0.2) x 10(-5). The results for B-0 -> J/psi pi(+)pi(-) are preliminary., 2008年, 2007 EUROPHYSICS CONFERENCE ON HIGH ENERGY PHYSICS, PTS 1-12, 110, doi;web_of_science研究論文（国際会議プロシーディングス）
Study of B̄0→D0π+π- decays
We report the results of a study of neutral B meson decays to the D0π+π- final state, where the D0 is fully reconstructed. The results are obtained from an event sample containing 388×106 BB̄-meson pairs collected in the Belle experiment at the KEKB e+e- collider. The total branching fraction of the three-body decay B(B̄0→D0π+π-)=(8.4±0. 4(stat)±0.8(syst))×10-4 has been measured. The intermediate resonant structure of these three-body decays has been studied. From a Dalitz plot analysis we have obtained the product of the branching fractions for D2*+ and D0*+ production: B(B̄0→D2*+π-) ×B(D2*+→D0π+)=(2.15±0.17(stat)±0.29(syst) ±0.12(mod))×10-4, and B(B̄0→D0*+π-) ×B(D0*+→D0π+)=(0.60±0.13(stat)±0.15(syst) ±0.22(mod))×10-4. This is the first observation of the B̄0→D0*+π- decay. The B̄0→D0ρ0 and D0f2 branching fractions are measured to be: B(B̄0→D0ρ0)=(3. 19±0.20(stat)±0.24(syst)±0.38(mod))×10-4, and B(B̄0→D0f2)=(1.20±0.18(stat)±0.21(syst)±0.32(mod) )×10-4. © 2007 The American Physical Society., 2007年07月, Physical Review D - Particles, Fields, Gravitation and Cosmology, 76 (1), doi;web_of_science;url研究論文（学術雑誌）
Measurement of CP asymmetry in a time-dependent dalitz analysis of B0→(ρπ)0 and a constraint on the quark mixing matrix angle 2
We present a measurement of CP asymmetry using a time-dependent Dalitz plot analysis of B0→π+π-π0 decays based on a 414fb-1 data sample containing 449×106BB̄ pairs. The data was collected on the Υ(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. Combining our analysis with information on charged B decay modes, we perform a full Dalitz and isospin analysis and obtain a constraint on the CKM angle 2, 68°< 2<95° as the 68.3% confidence interval for the 2 solution consistent with the standard model (SM). A large SM-disfavored region also remains. © 2007 The American Physical Society., 2007年06月, Physical Review Letters, 98 (22), doi;web_of_science;url研究論文（学術雑誌）
Evidence for D0-D̄0 mixing
We observe evidence for D0-D̄0 mixing by measuring the difference in the apparent lifetime when a D0 meson decays to the CP eigenstates K+K- and π+π- and when it decays to the final state K-π+. We find the relative difference of the lifetimes yCP to be [1.31±0.32(stat)±0.25(syst)] %, 3.2 standard deviations from zero. We also search for a CP asymmetry between D0 and D̄0 decays; no evidence for CP violation is found. These results are based on 540fb-1 of data recorded by the Belle detector at the KEKB e+e- collider. © 2007 The American Physical Society., 2007年05月, Physical Review Letters, 98 (21), doi;web_of_science;url研究論文（学術雑誌）
Moments of the electron energy spectrum and partial branching fraction of B→Xceν decays at the Belle detector
We report a measurement of the inclusive electron energy spectrum for charmed semileptonic decays of B mesons in a 140fb-1 data sample collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. We determine the first four moments of the electron energy spectrum for threshold values of the electron energy between 0.4 and 2.0 GeV. In addition, we provide values of the partial branching fraction (zeroth moment) for the same electron threshold energies, and independent measurements of the B+ and B0 partial branching fractions at 0.4 GeV and 0.6 GeV electron threshold energies. We measure the independent B+ and B0 partial branching fractions with electron threshold energies of 0.4 GeV to be ΔB(B+→Xceν)=(10. 79±0.25(stat.)±0.27(sys.))% and ΔB(B0→Xceν)=(10. 08±0.30(stat.)±0.22(sys.))%. Full correlations between all measurements are evaluated. © 2007 The American Physical Society., 2007年02月02日, Physical Review D - Particles, Fields, Gravitation and Cosmology, 75 (3), doi;url研究論文（学術雑誌）
Measurement of inclusive Ds, D0, and J/ψ rates and determination of the Bs(*)B̄s(*) production fraction in bb̄ events at the Υ(5S) resonance
The inclusive production of Ds, D0, and J/ψ mesons is studied using a 1.86fb-1 data sample collected on the Υ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. The number of bb̄ events in this Υ(5S) data sample is determined. We measure the branching fractions B(Υ(5S)→DsX)/2=(23.6±1.2±3.6)%, B(Υ(5S)→D0X)/2=(53.8±2.0±3.4)%, and B(Υ(5S)→J/ ψX)/2=(1.030±0.080±0.067)%. From the Ds and D0 inclusive branching fractions the ratio fs=(18.0±1.3±3.2)% of Bs(*)B̄s(*) to the total bb̄ quark pair production at the Υ(5S) energy is obtained in a model-dependent way. © 2007 The American Physical Society., 2007年02月, Physical Review Letters, 98 (5), doi;web_of_science;url研究論文（学術雑誌）
Search for B+→J/ψη′K+ and B0→J/ψη′KS0 decays
We report the results of searches for B+→J/ψη′K+ and B0→J/ψη′KS0 decays, using a sample of 388×106 BB̄ pairs collected with the Belle detector at the Υ(4S) resonance. No statistically significant signal is found for either of the two decay modes and upper limits for the branching fractions are determined to be B(B+→J/ψη′K+)<8.8×10-5 and B(B0→J/ ψη′KS0)<2.5×10-5 at 90% confidence level. © 2007 The American Physical Society., 2007年01月, Physical Review D - Particles, Fields, Gravitation and Cosmology, 75 (1), doi;web_of_science;url研究論文（学術雑誌）
Observation of time-dependent CP violation in B-0 ->eta K-'(0) decays and improved measurements of CP asymmetries in B-0 ->phi K-0, (KSKSKS0)-K-0-K-0 and B-0 -> J/psi K-0 decays
We present improved measurements of CP-violation parameters in B-0 -> phi K-0, eta K-'(0), (KSKSKS0)-K-0-K-0 decays based on a sample of 535 x 10(6) B (B) over bar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. We obtain sin2 phi(eff)(1) = +0.64 +/- 0.10(stat) +/- 0.04(syst) for B-0 -> eta K-'(0), +0.50 +/- 0.21(stat) +/- 0.06(syst) for B-0 ->phi K-0, and +0.30 +/- 0.32(stat) +/- 0.08(syst) for B-0 -> (KSKSKS0)-K-0-K-0 decays. We have observed CP violation in the B-0 -> eta K-'(0) decay with a significance of 5.6 standard deviations. We also perform an improved measurement of CP asymmetries in B-0 -> J/psi K-0 decays and obtain sin2 phi(1) = +0.642 +/- 0.031(stat) +/- 0.017(syst)., 2007年01月, PHYSICAL REVIEW LETTERS, 98 (3), 031802, doi;web_of_science研究論文（学術雑誌）
New States in B decays with "hidden charm"
Thanks to excellent luminosity of the KEKB e(+)e(-) asymmetric collider, several new resonances with "hidden charm" have been observed in B meson decays by the Belle experiment. In this report, two resonances of X(3872) and Y(3940) which were found in B decays, are described., 2006年12月, NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS, 162, 309 - 311, doi;web_of_science研究論文（国際会議プロシーディングス）
Evidence of the purely leptonic decay B-→τ-ν̄τ
We present the first evidence of the decay B-→τ-ν̄τ, using 414fb-1 of data collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. Events are tagged by fully reconstructing one of the B mesons in hadronic modes. We detect the signal with a significance of 3.5 standard deviations including systematics and measure the branching fraction to be B(B-→τ-ν̄τ)=(1.79-0.49+0.56(stat) -0.51+0.46(syst))×10-4. This implies that fB=0.229-0.031+0.036(stat)-0. 037+0.034(syst)GeV and is the first direct measurement of this quantity. © 2006 The American Physical Society., 2006年12月, Physical Review Letters, 97 (25), doi;web_of_science;url研究論文（学術雑誌）
Observation of new states decaying into Λc+K-π+ and Λc+KS0π
We report the first observation of two charmed strange baryons that decay into Λc+K-π+. The broader of the two states is measured to have a mass of 2978.5±2.1±2.0MeV/c2 and a width of 43.5±7.5±7. 0MeV/c2. The mass and width of the narrow state are measured to be 3076.7±0.9±0.5MeV/c2 and 6.2±1.2±0.8MeV/c2, respectively. We also perform a search for the isospin partner states that decay into Λc+KS0π- and observe a significant signal at the mass of 3082.8±1.8±1.5MeV/c2. The data used for this analysis were accumulated at or near the Υ(4S) resonance, using the Belle detector at the e+e- asymmetric-energy collider KEKB. The integrated luminosity of the data sample used is 461.5fb-1. © 2006 The American Physical Society., 2006年10月, Physical Review Letters, 97 (16), doi;web_of_science;url研究論文（学術雑誌）
Measurement of forward-backward asymmetry and Wilson coefficients in Bâ†'K*l+l-
We report the first measurement of the forward-backward asymmetry and the ratios of Wilson coefficients A9/A7 and A10/A7 in Bâ†' K*â.,"+â.,"-, where â.," represents an electron or a muon. We find evidence for the forward-backward asymmetry with a significance of 3.4Ï. The results are obtained from a data sample containing 386 106†â€BB pairs that were collected on the Î\(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. © 2006 The American Physical Society., 2006年06月, Physical Review Letters, 96 (25), doi;web_of_science;url研究論文（学術雑誌）
Evidence for large direct CP violation in B±→ρ(770) 0K± from analysis of three-body charmless B±→K±π ±π± decays
We report results on a Dalitz analysis of three-body charmless B±→K±π±π decay including searches for direct CP violation. We report the first observation of the decay B±→f2(1270) K± with a statistical significance above 6σ. We also observe first evidence for large direct CP violation in the B±→ρ(770) 0K± channel. The results are obtained with a data sample that contains 386×106 BB̄ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. © 2006 The American Physical Society., 2006年06月, Physical Review Letters, 96 (25), doi;web_of_science;url研究論文（学術雑誌）
Observation of b→dγ and determination of |Vtd/Vts|
We report the observation of the flavor-changing neutral current process b→dγ using a sample of 386×106 B meson pairs accumulated by the Belle detector at the KEKB e+e- collider. We measure branching fractions for the exclusive modes B-→ρ-γ, B̄0→ρ0γ, and B̄0→ωγ. Assuming that these three modes are related by isospin, we find B(B̄→(ρ,ω)γ)=(1.32-0.31+0.34(stat)-0.09+0.10(syst)) ×10-6 with a significance of 5.1σ. This result is used to determine the ratio of Cabibbo-Kobayashi-Maskawa matrix elements |Vtd/Vts| to be 0.199-0.025+0.026(exp)-0.015+0.018(theor). © 2006 The American Physical Society., 2006年06月, Physical Review Letters, 96 (22), doi;web_of_science;url研究論文（学術雑誌）
Measurement of the branching fraction, polarization, and CP asymmetry for B-0 ->rho(+)rho(-) decays, and determination of the Cabibbo-Kobayashi-Maskawa phase phi(2)
We have measured the branching fraction B, longitudinal polarization fraction f(L), and CP asymmetry coefficients A and S for B-0->rho(+)rho(-) decays with the Belle detector at the KEKB e(+)e(-) collider using 253 fb(-1) of data. We obtain B=[22.8 +/- 3.8(stat)(-2.6)(+2.3)(syst)]x10(-6), f(L)=0.941(-0.040)(+0.034)(stat)+/- 0.030(syst), A=0.00 +/- 0.30(stat)+/- 0.09(syst), and S=0.08 +/- 0.41(stat)+/- 0.09(syst). These values are used to constrain the Cabibbo-Kobayashi-Maskawa phase phi(2); the solution consistent with the standard model is phi(2)=(88 +/- 17)degrees or 59 degrees <phi 2 < 115 degrees at 90% C.L., 2006年05月, PHYSICAL REVIEW LETTERS, 96 (17), 171801, doi;web_of_science研究論文（学術雑誌）
Improved constraints on D0-D̄0 mixing in D0→K+π- Decays from the Belle detector
We report the results of a search for D0-D̄0 mixing in D0→K+π- decays based on 400fb-1 of data accumulated by the Belle detector at KEKB. Both assuming CP conservation and allowing for CP violation, we fit the decay-time distribution for the mixing parameters x′ and y′, as well as for the parameter RD, the ratio of doubly Cabibbo-suppressed decays to Cabibbo-favored decays. The 95% confidence level region in the (x′2,y′) plane is obtained using a frequentist method. Assuming CP conservation, we find x′2<0.72×10-3 and -9.9×10-3<y′<6.8×10-3 at the 95% confidence level; these are the most stringent constraints on the mixing parameters to date. The no-mixing point (0,0) has a confidence level of 3.9%. Assuming no mixing, we measure RD=(0.377±0.008±0.005)%. © 2006 The American Physical Society., 2006年04月, Physical Review Letters, 96 (15), doi;web_of_science;url研究論文（学術雑誌）
Measurement of branching fractions for B -> X c1(2) K (K*) at Belle
We have measured the branching fractions for the exclusive decay modes B -> chi(c1(2)) K(K*) using a 140 fb(-1) data sample collected by the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The measured branching fractions for B+ -> chi(c1) K+, B-0, chi(c1) K-0, B-0 -> chi(c1) K*(0) and B+ -> chi(c1) K*(+) decay modes are (4.5 +/- 0.2 +/- 0.5) x 10(-4), (3.5 +/- 0.3 +/- 0.5) x 10(-4), (3.1 +/- 0.3 +/- 0.7) x 10(-4) and (4.1 +/- 0.6 +/- 0.9) x 10(-4), respectively, where the first error is statistical and the second error is systematic. We do not observe statistically significant signals for the B -> chi(c2) K(K*) decay modes and set upper limits at the 90% confidence level. We also study the helicity distribution for B -> chi(c1) K* decay mode and show that the longitudinal polarization component is dominant. (c) 2006 Elsevier B.V. All rights reserved., 2006年03月, PHYSICS LETTERS B, 634 (2-3), 155 - 164, doi;web_of_science研究論文（学術雑誌）
Search for the Θ(1540)+ pentaquark using kaon secondary interactions at Belle
Using kaon secondary interactions in the material of the Belle detector, we search for both inclusive and exclusive production of the Θ(1540) +. We set an upper limit of 2.5% at the 90% C.L. on the ratio of the Θ(1540)+ to Λ(1520) inclusive production cross sections. We also search for the Θ(1540)+ as an intermediate resonance in the charge exchange reaction K+n→pKS0. We set an upper limit of ΓΘ+<0.64 MeV at the 90% C.L. for m Θ+=1.539 MeV/c2. These results are obtained from a 397 fb-1 data sample collected with the Belle detector near the Υ(4S) resonance, at the KEKB asymmetric energy e+e- collider. © 2005 Elsevier B.V. All rights reserved., 2006年01月, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 632 (2-3), 173 - 180, doi;web_of_science;url研究論文（学術雑誌）
Search for lepton and baryon number violating τ-decays into Λ̄π-and Λπ-
We have searched for τ lepton decays, τ-→Λ̄π- and τ-→Λπ-, that simultaneously violate the conservation of the lepton (L) and baryon (B) number using a data sample of 154 fb-1 collected with the Belle detector at the KEKB e+e- asymmetric-energy collider. No evidence for a signal was found in either of the decay modes and we set the following upper limits for the branching fractions: B(τ-→Λ̄π-) <1.4×10-7 and B(τ-→Λπ-)<0.72×10-7 at the 90% confidence level. This is the first search ever performed for these modes. © 2005 Elsevier B.V. All rights reserved., 2006年01月, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 632 (1), 51 - 57, doi;web_of_science;url研究論文（学術雑誌）
Measurement of branching fraction and direct CP asymmetry in B0→ρ0π0 decays
We report a measurement of the branching fraction of the decay B0→ρ0π0, using 386×106 BB̄ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We detect 51-13+14 signal events with a significance of 4.2 standard deviations, including systematic uncertainties, and measure the branching fraction to be B(B0→ρ0π0)=(3.12-0.82+0.88(stat)±0.33(syst)-0. 68+0.50(model))×10-6. We also perform the first measurement of direct CP violating asymmetry in this mode. © 2006 The American Physical Society., 2006年, Physical Review D - Particles, Fields, Gravitation and Cosmology, 73 (11), doi;url研究論文（学術雑誌）
Measurement of the wrong-sign decays D0→K+π-π0 and D0→K+π-π+π-, and search for CP violation
Using 281fb-1 of data from the Belle experiment recorded at or near the Υ(4S) resonance, we have measured the rates of the "wrong-sign" decays D0→K+π-π0 and D0→K+π-π+π- relative to those of the Cabibbo-favored decays D0→K-π+π0 and D0→K-π+π+π-. These wrong-sign decays proceed via a doubly Cabibbo-suppressed amplitude or via D0-D̄0 mixing; the latter has not yet been observed. We obtain RWS(Kππ0)=[0.229±0.015(stat)-0.009+0.013(syst)]% and RWS(K3π)=[0.320±0.018(stat)-0.013+0.018(syst)]%. The CP asymmetries are measured to be -0.006±0.053 and -0.018±0.044 for the K+π-π0 and K+π-π+π- final states, respectively. © 2005 The American Physical Society., 2005年12月, Physical Review Letters, 95 (23), doi;web_of_science;url研究論文（学術雑誌）
Determination of parallel to V-ub parallel to from measurements of the inclusive charmless semileptonic partial rates of B mesons using full reconstruction tags
We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element parallel to V(ub)parallel to, based on 253 fb(-1) of data collected by the Belle detector at the KEKB e(+)e(-) asymmetric collider. Events are tagged by fully reconstructing one of the B mesons, produced in pairs from Upsilon(4S). The signal for b -> u semileptonic decay is distinguished from the b -> c background using the hadronic mass M-X, the leptonic invariant mass squared q(2) and the variable P(+)equivalent to E-X-parallel to p ->(X)parallel to. The results are obtained for events with p(center dot)(*)>= 1 GeV/c, in three kinematic regions (1) M-X< 1.7 GeV/c(2), (2) M-X< 1.7 GeV/c(2) combined with q(2)> 8 GeV2/c(2), and by (3) P+< 0.66 GeV/c. The matrix element parallel to V(ub)parallel to is found to be (4.09 +/- 0.19 +/- 0.20(-0.15)(+0.14)+/- 0.18)x10(-3), where the errors are statistical, systematic including Monte Carlo modeling, theoretical, and from shape function parameter determination, respectively., 2005年12月, PHYSICAL REVIEW LETTERS, 95 (24), doi;web_of_science;url研究論文（学術雑誌）
Time-dependent C P violation effects in partially reconstructed B0→ D*∓π±decays
We report measurements of time-dependent decay rates for B0→ D*∓π±decays and extraction of C P violation parameters related to φ3. We use a partial reconstruction technique, whereby signal events are identified using information only from the primary pion and the charged pion from the decay of the D*∓. The analysis uses 140 fb-1of data accumulated at the γ (4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e-collider. We measure the C P violation parameters S+= 0.035 ± 0.041 (stat) ± 0.018 (syst) and S-= 0.025 ± 0.041 (stat) ± 0.018 (syst). © 2005 Elsevier B.V. All rights reserved., 2005年09月, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 624 (1-2), 11 - 21, doi;web_of_science;url研究論文（学術雑誌）
Improved evidence for direct CP violation in B0 ->pi(+)pi(-) decays and model-independent constraints on phi(2)
We present a new measurement of the time-dependent CP-violating parameters in B-0 ->pi(+)pi(-) decays with 275x10(6) B (B) over bar pairs collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider operating at the Upsilon(4S) resonance. We find 666 +/- 43 B-0 ->pi(+)pi(-) events and measure the CP-violating parameters: S-pi pi=-0.67 +/- 0.16(stat)+/- 0.06(syst) and A(pi pi)=+0.56 +/- 0.12(stat)+/- 0.06(syst). We find evidence for large direct CP violation with a significance greater than 4 standard deviations for any S-pi pi value. Using isospin relations, we obtain 95.4% confidence intervals for the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle phi(2) of 0 degrees <phi(2)< 19 degrees and 71 degrees <phi(2)< 180 degrees., 2005年09月, PHYSICAL REVIEW LETTERS, 95 (10), 101801, doi;web_of_science研究論文（学術雑誌）
Observation of B--> J/psi Lambda(p)over-bar and searches for B--> J/psi Sigma(0)(p)over-bar and B-0 -> J/psi p(p)over-bar decays
We report the observation of B--> J/psi Lambda(p) over bar and searches for B--> J/psi Sigma(0)(p) over bar and B-0-> J/psi p (p) over bar decays, using a sample of 275x10(6) B (B) over bar pairs collected with the Belle detector at the Upsilon(4S) resonance. We observe a signal of 17.2 +/- 4.1 events with a significance of 11.1 sigma and obtain a branching fraction of B(B--> J/psi Lambda(p) over bar)=11.6 +/- 2.8(stat)(-2.3)(+1.8)(sys)x10(-6). No signal is found for either of the two decay modes, B--> J/psi Sigma(0)(p) over bar and B-0-> J/psi p (p) over bar, and upper limits for the branching fractions are determined to be B(B--> J/psi Sigma(0)(p) over bar)< 1.1x10(-5) and B(B-0-> J/psi p (p) over bar)< 8.3x10(-7) at 90% confidence level., 2005年09月, PHYSICAL REVIEW D, 72 (5), 051105, doi;web_of_science研究論文（学術雑誌）
Measurement of time-dependent CP-violating asymmetries in B0→Ks0Ks0Ks0 decay
We present a measurement of CP-violation parameters in the B0→KS0KS0KS0 decay based on a sample of 275×106 BB̄ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. One neutral B meson is fully reconstructed in the decay B0→KS0KS0KS0, and the flavor of the accompanying B meson is identified from its decay products. CP-violation parameters are obtained from the asymmetry in the distributions of the proper-time interval between the two B decays: S=+1.26±0.68(stat)±0.20(syst) and A=+0.54±0. 34(stat)±0.09(syst). © 2005 The American Physical Society., 2005年08月, Physical Review Letters, 95 (6), doi;web_of_science;url研究論文（学術雑誌）
Studies of CP violation in B -> J/psi Kappa(*) decays
CP violation in B -> J/psi K-* decays is studied using an angular analysis in a data sample of 253 fb(-1) recorded with the Belle detector at the KEKB e(+)e(-) collider. The flavor separated measurements of the decay amplitudes indicate no evidence for direct CP violation. T-odd CP violation is studied using the asymmetries in triple product correlations, and the results are consistent with the standard model null predictions. The time-dependent angular analysis gives the following values of CP-violating parameters: sin2 phi(1)=0.24 +/- 0.31 +/- 0.05 and cos2 phi(1)=0.56 +/- 0.79 +/- 0.11., 2005年08月, PHYSICAL REVIEW LETTERS, 95 (9), 091601, doi;web_of_science研究論文（学術雑誌）
Evidence for B0→D+D- and observation of B-→D0D- and B-→D0D*- decays
We report evidence for B0→D+D- and the first observation of the decay modes B-→D0D- and B-→D0D*- based on a sample of 152×106 BB̄ events collected by the Belle detector at KEKB. The branching fractions for B0→D+D-, B-→D0D-, and B-→D0D*- are found to be (1.91±0.51±0.30)×10-4, (4.83±0.78±0.58) ×10-4, and (4.57±0.71±0.56)×10-4, respectively. Charge asymmetries in the B-→D0D- and B-→D0D*- channels are consistent with zero. © 2005 The American Physical Society., 2005年07月, Physical Review Letters, 95 (4), doi;web_of_science;url研究論文（学術雑誌）
Branching fraction, polarization and CP-violating asymmetries in B 0→D*+D*- decays
We present measurements of the branching fraction, the polarization parameters and CP-violating asymmetries in B0→D*+D *- decays using a 140 fb-1 data sample collected at the Υ(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. We obtain B(B0→D*+D*-)=[0. 81±0.08(stat)±0.11(syst)]×10-3, R⊥=0.19±0. 08(stat)±0.01(syst), R0=0.57±0.08(stat)±0.02(syst), S=-0.75±0.56(stat)±0.12(syst) and A=-0.26±0.26(stat) ±0.06(syst). Consistency with Standard Model expectations is also discussed., 2005年07月, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 618 (1-4), 34 - 42, doi;web_of_science;url研究論文（学術雑誌）
Measurement of polarization and triple-product correlations in B→K* decays
We present measurements of decay amplitudes and triple-product correlations in B→K* decays based on 253fb-1 of data recorded at the Υ(4S) resonance with the Belle detector at the KEKB e+e- storage ring. The decay amplitudes for the three different helicity states are determined from the angular distributions of final-state particles. The longitudinal polarization amplitudes are found to be 0.45±0.05±0.02 for B0→K*0 and 0.52±0.08±0.03 for B+→K*+ decays. CP- and T-odd CP-violating triple-product asymmetries are measured to be consistent with zero. © 2005 The American Physical Society., 2005年06月, Physical Review Letters, 94 (22), doi;web_of_science;url研究論文（学術雑誌）
Measurement of the time-dependent CP-violating asymmetry in BO→KSOπOγ decays
We present a new measurement of CP-violation parameters in B0→KS0π0γ decay based on a sample of 275×106 BB̄ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. One of the B mesons is fully reconstructed in the B0→KS0π0γ decay. The flavor of the accompanying B meson is identified from its decay products. CP-violation parameters are obtained from the asymmetry in the distribution of the proper time intervals between the two B decays. We obtain SKS0π0γ=-0.58-0.38+0.46(stat)±0.11(syst) and AKS0π0γ=+0.03±0.34(stat)±0.11(syst), for the KS0π0 invariant mass covering the full range up to 1.8GeV/c2. We also measure the CP-violation parameters for the case B0→K*0(→KS0π0)γ and obtain SK*0γ=-0.79-0.50+0.63(stat)±0.10(syst) for AK*0γ fixed at 0. © 2005 The American Physical Society., 2005年06月, Physical Review Letters, 94 (23), doi;web_of_science;url研究論文（学術雑誌）
Observation of a near-threshold omega J/psi mass enhancement in exclusive B -> K omega J/psi decays
We report the observation of a near-threshold enhancement in the omega J/psi invariant mass distribution for exclusive B -> K omega J/psi decays. The results are obtained from a 253 fb(-1) data sample that contains 275x10(6) B(B) over bar pairs that were collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e(+)e(-) collider. The statistical significance of the omega J/psi mass enhancement is estimated to be greater than 8 sigma., 2005年05月, PHYSICAL REVIEW LETTERS, 94 (18), 182002, doi;web_of_science研究論文（学術雑誌）
Search for B-0 -> J/psi D-0 and B+ -> J/psi D-0 pi(+) decays
We report the results of a search for the decay modes B-0 -> J/psi(D) over bar (0) and B+ -> J/psi(D) over bar (0)pi(+). The analysis is based on 140 fb(-1) of data accumulated by the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. No significant signals are observed and we determine the branching fraction upper limits B(B-0 -> J/psi(D) over bar (0)) < 2.0 x 10(-5) and b(B+-> J/psi(D) over bar (0)pi(+)) < 2.5 x 10(-5) at 90% confidence level. These results rule out the explanation of the excess in the low momentum region of the inclusive J/psi spectrum as intrinsic charm content in the B meson. The branching fractions of the corresponding nonresonant decay channels are also reported., 2005年05月, PHYSICAL REVIEW D, 71 (9), 091107, doi;web_of_science研究論文（学術雑誌）
Improved measurement of CP-violation parameters sin2 phi(1) and |lambda|, B meson lifetimes, and B-0-(B)over-bar(0) mixing parameter Delta m(d)
We present a precise measurement of the standard model CP-violation parameter sin2 phi(1), the direct CP violation parameter vertical bar lambda vertical bar, the lifetimes of charged and neutral B mesons and their ratio, and the B-0-(B) over bar (0) mixing parameter Delta m(d) based on a sample of 152x10(6) B(B) over bar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One of two B mesons is fully reconstructed in a CP-eigenstate or a flavor-eigenstate decay channel. The flavor of the accompanying B meson is identified from its decay products. From the distributions of the time interval between the two B meson decay points, we obtain sin2 phi(1)=0.728 +/- 0.056(stat)+/- 0.023(syst), vertical bar lambda vertical bar=1.007 +/- 0.041(stat)+/- 0.033(syst), tau(B)(0)=[1.534 +/- 0.008(stat)+/- 0.010(syst)] ps, tau(B)(+)=[1.635 +/- 0.011(stat)+/- 0.011(syst)] ps, tau(B)(+)/tau(B)(0)=1.066 +/- 0.008(stat)+/- 0.008(syst) and Delta m(d)=[0.511 +/- 0.005(stat)+/- 0.006(syst)] ps(-1). The results for sin2 phi(1) and vertical bar lambda vertical bar are consistent with the standard model expectations. The significance of the observed deviation from unity in the lifetime ratio exceeds 5 standard deviations., 2005年04月, PHYSICAL REVIEW D, 71 (7), 072003, doi;web_of_science研究論文（学術雑誌）
Observation of B+→K+ηγ
We report measurements of radiative B decays with Kηγ final states, using a data sample of 253 fb-1 recorded at the Υ(4S) resonance with the Belle detector at the KEKB e+e- storage ring. We observe B+→K+ηγ for the first time with a branching fraction of (8.4±1.5(stat)-0.9+1.2(syst))×10-6 for MKη<2.4 GeV/c2, and find evidence of B0→K 0ηγ. We also search for B→K3*(1780) γ. © 2005 Elsevier B.V. All rights reserved., 2005年03月, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 610 (1-2), 23 - 30, doi;web_of_science;url研究論文（学術雑誌）
B physics and CP violation at Belle
We report measurements of CP violation in B meson system using a large amount data sample collected by the Belle detector at KEKB e(+)e(-) collider. In this report, the measurements of CP violation in various B decays are described, mainly measurements of time-dependent CP violation in neutral B meson system, as well as direct CP violation in Dalitz distribution., 2005年, Particles, Strings, and Cosmology, 805, 106 - 109, web_of_science研究論文（国際会議プロシーディングス）
Measurement of the branching fraction and CP asymmetry in B+ρ+π0
We report a measurement of the branching fraction for the decay B+→ ρ+π0based on a 140 fb-1data sample collected with the Belle detector at the KEKB asymmetric e+e-collider. We measure the branching fraction B(B+→+π0) = (13.2 ± 2.3(stat)-1.9+(syst)) × 10-6, and the CP-violating asymmetry ACP(B± ρ±π0) = 0.06 ± 0.17(stat)-0.05+0.04(syst).© 2005 The American Physical Society., 2005年01月, Physical Review Letters, 94 (3), doi;web_of_science;url研究論文（学術雑誌）
Study of time-dependent CP violation in B-0 -> J/psi pi(0) decays
We report a measurement of CP asymmetry parameters in the decay B-0((B) over bar (0))-->J/psipi(0), which is governed by the b-->c(c) over bar d transition. The analysis is based on a 140 fb(-1) data sample accumulated at the Y(4S) resonance by the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson in the J/psipi(0) final state is fully reconstructed for events used in this analysis. The accompanying B meson flavor is identified by its decay products. From the distribution of proper-time intervals between the two B decays, we obtain the following CP-violating parameters: S-J/psipi(0)=-0.72+/-0.42(stat)+/-0.09(syst) and A(J/psipi)(0)=-0.01+/-0.29(stat)+/-0.03(syst)., 2004年12月, PHYSICAL REVIEW LETTERS, 93 (26), 261801, doi;web_of_science研究論文（学術雑誌）
Observation of large CP violation and evidence for direct CP violation in B0+p- decays
We report the first observation of CP violation in B(pp)(pp)(pp)(pp)(pp)(0+p- decays based on 152x106 U(4S)B (B) over bar decays collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct a B0+p- CP eigenstate and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two B meson decay points, we obtain A)(=+0.580.15(stat)0.07(syst) and S)(=-1.000.21(stat)0.07(syst). We rule out the CP-conserving case, A)(=S)(=0, at a level of 5.2 standard deviations. We also find evidence for direct CP violation with a significance at or greater than 3.2 standard deviations for any S) value., 2004年07月, PHYSICAL REVIEW LETTERS, 93 (2), 021601, doi;web_of_science研究論文（学術雑誌）
Measurement of the B→L*γ branching fractions and asymmetries
We report measurements of the radiative decay B→K*γ. The analysis is based on a data sample containing 85.0 × 106B meson pairs collected by the Belle detector at the KEKB storage ring. We measure branching fractions of β(B0→K*0γ) = (4.01±0.21±0.17)× 10-5and β(B+→K*+γ) = (4.25±0.31±0.24)× 10-5, where the first and second errors are statistical and systematic, respectively. The isospin asymmetry between B0and B+decay widths is measured to be Δ0+= + 0.012±0.044±0.026, assuming an equal production rate for B0B̄0and B+B-pairs from the γ(4S) resonance. We search for a partial rate asymmetry between CP conjugate modes, and find ACP(B→K*γ) = -0.015±0.0447plusmn;0.012. © 2004 The American Physical Society., 2004年06月, Physical Review D, 69 (11), doi;web_of_science;url研究論文（学術雑誌）
Search for B-→ J/ ψΛp̄ decay 017101
We report the results of a search for B-→ J/ ψ Λp̄ based on a data set of 78 fb-1data collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetrice-collider. No substantial signal is found, and we set the branching fraction upper limit Β(-→ J/ ψ Λp̄)<4. 1× 10-5at 90% confidence level. © 2004 The American Physical Society., 2004年01月, Physical Review D, 69 (1), doi;web_of_science;url研究論文（学術雑誌）
Observation of a Narrow Charmoniumlike State in ExclusiveB±→K±π+π−J/ψDecays
We report the observation of a narrow charmoniumlike state produced in the exclusive decay process B+/--->K(+/-)pi(+)pi(-)J/psi. This state, which decays into pi(+)pi(-)J/psi, has a mass of 3872.0+/-0.6(stat)+/-0.5(syst) MeV, a value that is very near the M-D(0)+M-D*0 mass threshold. The results are based on an analysis of 152M B-(B) over bar events collected at the Y(4S) resonance in the Belle detector at the KEKB collider. The signal has a statistical significance that is in excess of 10sigma., 2003年12月23日, Physical Review Letters, 91 (26), 262001, doi;web_of_science;url;url研究論文（学術雑誌）
Observation of B → K*ℓ+ℓ-
The observation of the flavor-changing neutral decay B → K*l+l- was reported. The branching fractions were calculated by assuming an equal production rate for charged and neutral B meson pairs. The measured branching fractions were found to be in agreement with the standard model predictions. The effect of systematic error was also included in the calculations., 2003年12月, Physical Review Letters, 91 (26), 2616011 - 2616016, doi;web_of_science;url研究論文（学術雑誌）
Measurement of time-dependent CP-violating asymmetries in B(0)->phi K(S)(0), K(+)K(-)K(S)(0), and eta(')K(S)(0) decays
We present an improved measurement of CP-violation parameters in B(0)-->phiK(S)(0), K(+)K(-)K(S)(0), and eta(')K(S)(0) decays based on a 140 fb(-1) data sample collected at the Y(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. One neutral B meson is fully reconstructed in one of the specified decay channels, and the flavor of the accompanying B meson is identified from its decay products. CP-violation parameters for each of the three modes are obtained from the asymmetries in the distributions of the proper-time intervals between the two B decays. We find that the observed CP asymmetry in the B-->phiK(S)(0) decay differs from the standard model (SM) expectation by 3.5 standard deviations, while the other cases are consistent with the SM., 2003年12月, PHYSICAL REVIEW LETTERS, 91 (26), 261602, doi;web_of_science研究論文（学術雑誌）
Observation of B ± → ρ ±ρ 0 decays
An overview is given of the first observation of the vector-vector (VV) decay mode Β +→ρ +ρ 0. These decays produce final states where both ρ mesons are either longitudinally or transversely polarized., 2003年11月, Physical Review Letters, 91 (22), doi;web_of_science;url研究論文（学術雑誌）
Measurement of Branching Fractions forB→ηcK(*)Decays
We report measurements of branching fractions for charged and neutral B-->eta(c)K decays where the eta(c) meson is reconstructed in the K(S)(0)K(+/-)pi(-/+), K(+)K(-)pi(0), K(*0)K(-)pi(+), and p (p) over bar decay channels. The neutral B-0 channel is a CP eigenstate and can be used to measure the CP violation parameter sin2phi(1). We also report the first observation of the B-0-->eta(c)K(*0) mode. The results are based on an analysis of 29.1 fb(-1) of data collected by the Belle detector at KEKB., 2003年02月21日, Physical Review Letters, 90 (7), 6, doi;web_of_science;url;url研究論文（学術雑誌）
Radiative B meson decays into Kπγ and Kππγ final states
The radiative Β decays with the K+π-γ and K+π-π+γ final states were studied. For K+π-γ, B0→K2*(1430)0- γ, B0→K*(1410)0γ, and non-resonant components were considered. It was found that only the first one is significant. For B+→ K+π-π+γ, the decay mode was observed and the branching fraction measured. The branching fractions were consistent with the sum of predicted rates of resonant decays., 2002年12月, Physical Review Letters, 89 (23), doi;web_of_science;url研究論文（学術雑誌）
Charmless hadronic two-body B meson decays
We report the results of a study of two-body B meson decays to the complete set of (Formula presented) (Formula presented) and (Formula presented) final states. The study is performed on a data sample of (Formula presented) million (Formula presented) events recorded on the (Formula presented) resonance by the Belle experiment at KEKB. We observe significant signals in all (Formula presented) final states and in the (Formula presented) and (Formula presented) final states. We set limits on the (Formula presented) and (Formula presented) final states. A search is performed for partial-rate asymmetries between conjugate states for flavor-specific final states. © 2002 The American Physical Society., 2002年11月26日, Physical Review D - Particles, Fields, Gravitation and Cosmology, 66, doi;urlObservation of B± → ωK± decay
In factorization models with Nc≃2-3, where Nc is the effective number of colors, the ωπ mode is larger than the ωK mode by a factor of 2 or more. This result is borne out by further studies in the QCD factorization and perturbative QCD (pQCD). This paper reports on the measurements of B-→ωK- and ωπ- decays that indicate that the former is more prominent., 2002年11月, Physical Review Letters, 89 (19), doi;web_of_science;url研究論文（学術雑誌）
Improved measurement of mixing-induced CP violation in the neutral B meson system
We present an improved measurement of the standard model CP violation parameter sin 2phi(1) (also known as sin 2beta) based on a sample of 85x10(6) B (B) over bar pairs collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson is reconstructed in a J/psiK(S)(0), psi(2S)K(S)(0), chi(c1)K(S)(0), eta(c)K(S)(0), J/psiK*(0), or J/psiK(L)(0) CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time interval between the two B meson decay points, we obtain sin 2phi(1)=0.719+/-0.074(stat)+/-0.035(syst)., 2002年10月, PHYSICAL REVIEW D, 66 (7), 071102, doi;web_of_science研究論文（学術雑誌）
Production of prompt charmonia in e+e- annihilation at √s ≈ 10.6 GeV
The production of prompt charmonia was studied using a 32.4 fb -1 data sample collected with the Belle detector. The Belle detector is a large solid-angle spectrometer equipped with a 1.5 T superconducting solenoid magnet. The results showed that the yield of prompt J/ψ mesons in the υ(4S) sample is compatible with that of continuum production., 2002年02月, Physical Review Letters, 88 (5), 520011 - 520016, doi;web_of_science;url研究論文（学術雑誌）
Measurement of branching fractions for B → ππ, Kπ and KK decays
Using BB events recorded in the Belle detector, the charge averaged branching fractions for B→π+π-, K+π-, K+π0, K0π0 were measured with statistically significant signals. The results confirm that B(B0→K+π-) is larger than B(B0→π+π-), and indicate that B(B+→h+π0) and B(B0→K0π0) seem to be larger than expected in relation to the B0→h+π- and B+→K0π+ modes based on isospin or penguin dominance arguments., 2001年09月, Physical Review Letters, 87 (10), doi;web_of_science;url研究論文（学術雑誌）
Observation of Cabibbo suppressed B → D(*)K- decays at Belle
By taking advantage of the good high momentum particle identification capability of Belle, signals were observed for the Cabibbo suppressed decays B → D0K-, D+K-, D*0K-, and D*+K-. Values for the ratios of branching fractions R = B (B → D(*)K-)/B(B → D(*)π-) showed good agreement, within errors, with naive model calculation., 2001年09月, Physical Review Letters, 87 (11), doi;web_of_science;url研究論文（学術雑誌）
A detailed test of the CsI(Tℓ) calorimeter for BELLE with photon beams of energy between 20 MeV and 5.4 GeV
2000年03月, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 441 (3), 401 - 426, doi;cinii_articles;web_of_science研究論文（学術雑誌）
MISC
Recent electroweak results from TRISTAN (Invited talk at XXXth Rencontres De Moribund)
1995年1992 progress report on B physics Task Force activities
1993年, KEK-93, (1)Total Hadronic Cross Section measurements at TOPAZ
1993年, KEK proceedings, (22), 63JLC-I
1993年, KEK report 92, (16)1992 progress report on B physics Task Force activities
1993年, KEK-93, (1)Total Hadronic Cross Section measurements at TOPAZ
1993年, KEK proceedings, (22), 63Progress report on physics and detector at KEK asymmetric B factory
1992年, KEK-92, (3)Progress report on physics and detector at KEK asymmetric B factory
1992年, KEK-92, (3)
書籍等出版物
パリティ2017年1月号「特集：物理科学、この1年」原子核物理の部「バリオン（3クォーク）・メソン（2クォーク）を超えるハドロンの出現」
丸善出版株式会社, 2017年パリティ2017年12月号「バリオンを超える多クォークハドロン」
丸善出版株式会社, 2017年
講演・口頭発表等
Belle studies of exotic hadrons with heavy flavors
International Conference on Exotic Atoms and Related Topics (EXA2017), 2017年09月14日口頭発表（招待・特別）
XYZ resonances at Belle
14th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2016), 2016年07月27日口頭発表（招待・特別）
Heavy hadron spectroscopy at Belle
Hadrons and Hadron Interactions in QCD 2015, 2015年口頭発表（招待・特別）
Belle/Belle II CsI(Tl)電磁カロリメーター
東北大学ELPH研究会C010「素粒子・原子核実験における全吸収型カロリメーターの実例と応用」, 2015年口頭発表（招待・特別）
Belle II 実験におけるハドロン物理の展望
日本物理学会第70回年次大会シンポジウム「多彩な実験プラットフォームによるハドロンの本質的自由度の探求」, 2015年シンポジウム・ワークショップパネル（指名）
Mixing induced CP violation in Bd decays
13th Flavor Physics and CP Violation (FPCP2015), 2015年口頭発表（招待・特別）
CP violation
XXVII International Symposium on Lepton Photon Interactions at High Energies (LP2015), 2015年Results on heavy-quark exotic hadrons at Belle and future perspectives
11th European Research Conference on Electromagnetic Interactions with Nucleons and Nuclei (EINN2015), 2015年Heavy hadron spectroscopy at Belle
Hadrons and Hadron Interactions in QCD 2015, 2015年Prospect at e+e- colliders
Hadron Physics symposium, 2014年Charm baryon spectroscopy at collider experiments
Mini workshop on "Structure and productions of charmed baryons II", 2014年Belleが切り拓いたエキゾチックハドロンの世界
日本物理学会2014年秋季大会（企画講演）, 2014年Prospect ar e+e- colliders
Hadron Physics symposium, 2014年Charm baryon spectroscopy at collider experiments
Mini workshop on "Structure and productions of charmed baryons II", 2014年Research of exotic hadrons at B-factory experiment Summary
2012年度「新ハドロン」領域研究会, 2013年SuperKEKB/Belle II
XV International Conference on Hadron Spectroscopy (Hadron2013), 2013年Research of exotic hadrons at B-factory experiment Summary
Workshop on "Elucidation of New Hadrons with a Variety of Flavors" - Grant-in-Aid for Scientific Research on Innovative Areas, 2013年Time-dependent CPV and mixing at B-factories
Cracow Epiphany Confernce - Present and Future B-physics, 2012年Angle averages from B-factories
The 7th Workshop on the CKM Unitarity Triangle (CKM 2012), 2012年Exotic hadrons at B-factory
2010年度「新ハドロン」領域研究会, 2011年Belleにおけるエキゾチックハドロンの探索
新学術領域「素核宇宙融合」×「新ハドロン」クロスオーバー研究会, 2011年Other charmonium and cc-like results at Belle
International Workshop on Heavy Quarkonia 2010 (QWG 7), 2010年Determination of phi1 from B0→K+K-KS, pi+pi-KS and KSKSKS
6th International Workshop on the CKM Unitarity Triangle (CKM 2010), 2010年Radiation Hardness Test of Pr:LuAG and BSO Scintillators
The 2010 IEEE Nuclear Science Symposium, Medical Imaging Conference(2010 NSS/MIC/RTSD), 2010年Determination of phi1 from B0→K+K-KS, pi+pi-KS and KSKSKS
6th International Workshop on the CKM Unitarity Triangle (CKM 2010), 2010年1G2-C2 素粒子実験Belleを題材とした高校生向けサイエンスキャンプの実践報告(科学教育各論(1),一般研究発表,転換期の科学教育:これからの科学的リテラシー)
年会論文集, 2008年08月08日, 2008年08月08日, 2008年08月08日, 日本科学教育学会, urlRecent electroweak results from TRISTAN (Invited talk at XXXth Rencontres De Moribund)
1995年, 1995年, 1995年CP非保存とフレーバー量子数非保存の研究が果たすべき新しい役割
日本物理学会第74回年次大会シンポジウム「宇宙観測と地上実験の協奏による素粒子標準模型の超越」, 2019年03月16日, 2019年03月16日, 2019年03月16日シンポジウム・ワークショップパネル（指名）
Heavy Flavor Hadron Physics at Belle and Belle II
10th anniversary J-PARC Symposium 2019, 2019年09月25日シンポジウム・ワークショップパネル（指名）
From CP violation to XYZ particles
日本物理学会2018年秋季大会シンポジウム「60 years Physical Review Letters」, 2018年09月15日, 2018年09月15日, 2018年09月15日シンポジウム・ワークショップパネル（指名）
エキゾチックハドロン研究との協働で何がわかるか
日本物理学会第73回年次大会シンポジウム「高エネルギー重イオン衝突実験と諸分野の協奏と発展」, 2018年03月22日シンポジウム・ワークショップパネル（指名）
Belle II experiment
8th International Conference on Quarks and Nuclear Physics (QNP2018), 2018年11月17日, 2018年11月13日, 2018年11月13日口頭発表（招待・特別）