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論文

Formation and evolution of carbonaceous asteroid Ryugu; Direct evidence from returned samples

中村 智樹*; 大澤 崇人; 他219名*

Science, 379(6634), p.eabn8671_1 - eabn8671_14, 2023/02

https://doi.org/10.1126/science.abn8671
 被引用回数：44 パーセンタイル：99.99(Multidisciplinary Sciences)

1から8mmのリュウグウ粒子16個の鉱物学的,岩石学的、および物理的特性は、それらがCIコンドライトに最も類似していることを示している。磁硫鉄鉱中のCO$$_{2}$$含有水の存在は、母天体が太陽系星雲のH$$_{2}$$OおよびCO$$_{2}$$のスノーラインを越えた領域で形成したことを示しており、ここでは、リュウグウの鉱物学に基づくと、小さなコンドリュールやCa, Alを含む非常に限られた量の高温物質がある。流体-岩石反応は、低温,高pH、および水/岩石の質量比が1未満の還元条件で発生し、リュウグウのサンプルで最も変化の少ない断片として残っているかんらん石-輝石に富む岩相を、リュウグウサンプルの主要な岩相であるフィロケイ酸塩-炭酸塩に富むものに変えた。リュウグウの母体の流体から磁鉄鉱が結晶化したとき、原始太陽系星雲はまだ存在していた可能性がある。

論文

Decay modes of the 9/2$$^-$$ isomeric state in $$^{183}$$Tl

Venhart, M.*; Andreyev, A. N.; Cubiss, J. G.*; Wood, J. L.*; Barzakh, A. E.*; Van Beveren, C.*; Cocolios, T. E.*; de Groote, R. P.*; 他19名*

Physical Review C, 105(3), p.034338_1 - 034338_9, 2022/03

https://doi.org/10.1103/PhysRevC.105.034338
 被引用回数：1 パーセンタイル：39.66(Physics, Nuclear)

The neutron-deficient region of isotopes around $$Z$$=82 is the best studied example of low-energy shape coexistence in nuclei. In this work, the internal transition decay and $$alpha$$ decay of the 53.3-ms isomeric state in $$^{183}$$Tl were studied at ISOLDE, CERN. The branching for the internal decay was measured to be 98.5(4)%, while the much weaker $$alpha$$decay branching is only about 1.4(4)%. The new results include the first identification of an $$E3$$ transition feeding the 3/2$$^+$$ excited state in $$^{183}$$Tl. Three $$alpha$$ decays from the $$^{183m}$$Tl isomer were also oserved, and revealed the population of a candidate 9/2$$^-$$ state in $$^{179}$$Au which has been linked to shape coexistence in the Au nuclei. It is expected that similarly weak $$alpha$$ decays from isomeric states may be found also in neighbouring Tl isotopes.

論文

Measurement of differential branching fractions of inclusive $${B to X_u , ell^+, nu_{ell}}$$ decays

Cao, L.*; 谷田 聖; Belle Collaboration*; 他199名*

Physical Review Letters, 127(26), p.261801_1 - 261801_8, 2021/12

https://doi.org/10.1103/PhysRevLett.127.261801
 被引用回数：1 パーセンタイル：34.04(Physics, Multidisciplinary)

The first measurements of differential branching fractions of inclusive semileptonic $${B to X_u , ell^+, nu_{ell}}$$ decays are performed using the full Belle data set of 711 fb$$^{-1}$$ of integrated luminosity at the $$Upsilon(4S)$$ resonance and for $$ell = e, mu$$. Differential branching fractions are reported as a function of the lepton momentum, the four-momentum-transfer squared, light-cone momenta, the hadronic mass, and the hadronic mass squared. They are obtained by subtracting the backgrounds from semileptonic $${B to X_c , ell^+, nu_{ell}}$$ decays and other processes, and corrected for resolution and acceptance effects. The measured distributions are compared to predictions from inclusive and hybrid $${B to X_u , ell^+, nu_{ell}}$$ calculations.

論文

Search for $$B^{0} to tau^pm ell^mp$$ ($$ell=e,mu$$) with a hadronic tagging method at Belle

Atmacan, H.*; 谷田 聖; Belle Collaboration*; 他219名*

Physical Review D, 104(9), p.L091105_1 - L091105_9, 2021/11

https://doi.org/10.1103/PhysRevD.104.L091105
 被引用回数：2 パーセンタイル：23.79(Astronomy & Astrophysics)

We present a search for the lepton-flavor-violating decays $$B^{0} to tau^pm ell^mp$$, where $$ell=(e,,mu)$$, using the full data sample of $$772 times 10^6$$ $$B overline{B}$$ pairs recorded by the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider. We use events in which one $$B$$ meson is fully reconstructed in a hadronic decay mode. The $$tau^pm$$ lepton is reconstructed indirectly using the momentum of the reconstructed $$B$$ and that of the $$ell^mp$$ from the signal decay. We find no evidence for $$B^{0} to tau^pm ell^mp$$ decays and set upper limits on their branching fractions at 90% confidence level of $$cal B$$($$B^{0} to tau^pm mu^{mp}$$)$$ < 1.5 times 10^{-5}$$ and $$cal B$$($$B^{0} to tau^pm e^{mp}$$)$$ < 1.6 times 10^{-5}$$.

論文

Measurement of the branching fraction of $$Lambda_c^+ to p omega$$ decay at Belle

Li, S. X.*; 谷田 聖; Belle Collaboration*; 他193名*

Physical Review D, 104(7), p.072008_1 - 072008_8, 2021/10

https://doi.org/10.1103/PhysRevD.104.072008
 被引用回数：3 パーセンタイル：33.83(Astronomy & Astrophysics)

Using 980.6 $$rm fb^{-1}$$ of data collected with the Belle detector operating at the KEKB asymmetric-energy $$e^+e^-$$ collider, we present a measurement of the branching fraction of the singly Cabibbo-suppressed decay $$Lambda_c^+ to p omega$$. A clear $$Lambda_c^+$$ signal is observed for $$Lambda_c^+ to p omega$$ with a statistical significance of 9.1 standard deviations, and we measure the ratio of branching fractions $${cal B}(Lambda_c^+ to p omega)/{cal B}(Lambda_c^+ to p K^- pi^+) = (1.32 pm 0.12 (rm stat) pm 0.10 (rm syst))times 10^{-2}$$, from which we infer the branching fraction $${cal B}(Lambda_c^+ to p omega) = (8.27 pm 0.75 (rm stat) pm 0.62 (rm syst) pm 0.42 (rm ref))times 10^{-4}$$. The first quoted uncertainty is statistical, the second systematic, and the third from the reference mode $$Lambda_c^+ to p K^- pi^+$$.

論文

Evidence for the decay $$Omega_{c}^{0} to pi^+Omega(2012)^- to pi^+ (bar{K}Xi)^{-}$$

Li, Y.*; 谷田 聖; Belle Collaboration*; 他190名*

Physical Review D, 104(5), p.052005_1 - 052005_9, 2021/09

https://doi.org/10.1103/PhysRevD.104.052005
 被引用回数：7 パーセンタイル：62.22(Astronomy & Astrophysics)

Using a data sample of 980~fb$$^{-1}$$ collected with the Belle detector operating at the KEKB asymmetric-energy $$e^+e^-$$ collider, we present evidence for the $$Omega(2012)^-$$ in the resonant substructure of $$Omega_{c}^{0} to pi^+ (bar{K}Xi)^{-}$$ ($$(bar{K}Xi)^{-}$$ = $$K^-Xi^0$$ + $$bar{K}^0 Xi^-$$) decays. The significance of the $$Omega(2012)^-$$ signal is 4.2$$sigma$$ after considering the systematic uncertainties. The ratio of the branching fraction of $$Omega_{c}^{0} to pi^{+} Omega(2012)^- to pi^+ (bar{K}Xi)^{-}$$ relative to that of $$Omega_{c}^{0} to pi^{+} Omega^-$$ is calculated to be 0.220 $$pm$$ 0.059(stat.) $$pm$$ 0.035(syst.). The individual ratios of the branching fractions of the two isospin modes are also determined, and found to be $${cal B}(Omega_{c}^0 to pi^+ Omega(2012)^-) times {cal B}(Omega(2012)^- to K^-Xi^0)/{cal B}(Omega_{c}^0 to pi^+ K^- Xi^0)$$ =(9.6 $$pm$$ 3.2(stat.) $$pm$$ 1.8(syst.))% and $${cal B}(Omega_{c}^0 to pi^+ Omega(2012)^-) times {cal B}(Omega(2012)^- to bar{K}^0 Xi^-)/{cal B}(Omega_{c}^0 to pi^+ bar{K}^0 Xi^-)$$ = (5.5 $$pm$$ 2.8(stat.) $$pm$$ 0.7(syst.))%.

論文

Search for the decay $$B_s^0 rightarrow eta^prime eta$$

Nisar, N. K.*; 谷田 聖; Belle Collaboration*; 他197名*

Physical Review D, 104(3), p.L031101_1 - L031101_8, 2021/08

https://doi.org/10.1103/PhysRevD.104.L031101
 被引用回数：0 パーセンタイル：12.34(Astronomy & Astrophysics)

We report the results of the first search for the decay $$B_s^0 rightarrow eta^prime eta$$ using $$121.4~textrm{fb}^{-1}$$ of data collected at the $$Upsilon(5S)$$ resonance with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider. We observe no significant signal and set a 90% confidence-level upper limit of $$6.5 times 10^{-5}$$ on the branching fraction of this decay.

論文

The Energy spectrum of forward photons measured by the RHICf experiment in $$sqrt{s}$$ = 510 GeV proton-proton collisions

佐藤 健太*; 谷田 聖; 他19名*

Proceedings of Science (Internet), 358, p.413_1 - 413_8, 2021/07

https://doi.org/10.22323/1.358.0413

The Relativistic Heavy Ion Collider forward (RHICf) experiment aims at understanding the high-energy hadronic interaction by measuring the cross sections of very forward neutral particles in proton-proton collisions at $$sqrt{s}$$ = 510 GeV. For the analysis of the photon measurement, the trigger efficiency and the particle identification performance are studied by using the Monte Carlo simulation data and the experimental data. In the RHICf operation, two kinds of trigger modes (Shower, HighEM) were implemented. The trigger efficiency of the Shower trigger is 100% for photons with the energies more than 20 GeV. The HighEM trigger is designed to detect high energy photons effectively, and the trigger efficiency of the HighEM trigger is 90% for photons with the energies more than 130 GeV. The correction factor for the photon identification is calculated by using the efficiency and purity. It is found that this correction does not make a sizeable effect on the shape of the energy spectrum because the energy dependency of the factor is small.

論文

Measurement of the resonant and nonresonant branching ratios in $$Xi_{c}^{0} rightarrow Xi^{0} K^+ K^-$$

McNeil, J. T.*; 谷田 聖; Belle Collaboration*; 他193名*

Physical Review D, 103(11), p.112002_1 - 112002_11, 2021/06

https://doi.org/10.1103/PhysRevD.103.112002
 被引用回数：2 パーセンタイル：23.79(Astronomy & Astrophysics)

Using the entire data sample of $$980$$ $$rm fb^{-1}$$ integrated luminosity collected with the Belle detector at the KEKB asymmetric-energy $$e^{+}e^{-}$$ collider, we present an amplitude analysis measuring the branching fractions of the Cabibbo-allowed, $$W$$-exchange resonant decay $$Xi_{c}^{0} rightarrow Xi^{0} phi (to K^+ K^-)$$ with a polarized $$phi$$ and the non-resonant decay via a direct process $$Xi_{c}^{0} rightarrow Xi^{0} K^+ K^-$$. We present these measurements, relative to the normalization mode $$Xi^{-}pi^{+}$$, and find branching ratios $$frac{mathcal{B}(Xi_{c}^{0} rightarrow Xi^{0} phi (rightarrow K^{+}K^{-}))}{mathcal{B}(Xi_{c}^{0} rightarrow Xi^{-} pi^{+})}$$ = $${rm 0.036 pm 0.004 (stat.) pm 0.002 (syst.)}$$ and $$frac{mathcal{B}(Xi_{c}^{0} rightarrow Xi^{0} K^{+} K^{-})}{mathcal{B}(Xi_{c}^{0} rightarrow Xi^{-} pi^{+})}$$ = $$ 0.039 pm 0.004 ({rm stat.}) pm 0.002 {rm (syst.)}$$ which suggest that only minor cusping peaks occur in the combinatorial background of $$Omega^{*-} to Xi^{0}K^{-}$$ due to these $$Xi_{c}^{0}$$ decays.

論文

Search for transitions from $$Upsilon(4S)$$ and $$Upsilon(5S)$$ to $$eta_b(1S)$$ and $$eta_b(2S)$$ with emission of an $$omega$$ meson

Oskin, P.*; 谷田 聖; Belle Collaboration*; 他198名*

Physical Review D, 102(9), p.092011_1 - 092011_8, 2020/11

https://doi.org/10.1103/PhysRevD.102.092011
 被引用回数：0 パーセンタイル：0.01(Astronomy & Astrophysics)

Using data collected in the Belle experiment at the KEKB asymmetric-energy $$e^+e^-$$ collider we search for transitions $$Upsilon(4S) rightarrow eta_b(1S)omega$$, $$Upsilon(5S) rightarrow eta_b(1S)omega$$ and $$Upsilon(5S) rightarrow eta_b(2S)omega$$. No significant signals are observed and we set 90% confidence level upper limits on the corresponding visible cross sections: $$0.2 ~textrm{pb}, 0.4 ~textrm{pb}$$ and $$1.9 ~textrm{pb}$$, respectively.

論文

First search for the $$eta_{c2}(1D)$$ in $$B$$ decays at Belle

Chilikin, K.*; 谷田 聖; Belle Collaboration*; 他194名*

Journal of High Energy Physics (Internet), 2020(5), p.34_1 - 34_22, 2020/05

https://doi.org/10.1007/JHEP05(2020)034
 被引用回数：2 パーセンタイル：17.52(Physics, Particles & Fields)

The first dedicated search for the $$eta_{c2}(1D)$$ is carried out using the decays $$B^+ rightarrow eta_{c2}(1D) K^+$$, $$B^0 rightarrow eta_{c2}(1D) K^0_S$$, $$B^0 rightarrow eta_{c2}(1D) pi^- K^+$$, and $$B^+ rightarrow eta_{c2}(1D) pi^+ K^0_S$$ with $$eta_{c2}(1D) to h_c gamma$$. No significant signal is found. For the $$eta_{c2}(1D)$$ mass range between $$3795$$ and $$3845 mathrm{MeV}/c^2$$, the branching-fraction upper limits are determined to be $$mathcal{B}(B^+ rightarrow eta_{c2}(1D) K^+) times mathcal{B}(eta_{c2}(1D) to h_c gamma) < 3.7 times 10^{-5}$$, $$mathcal{B}(B^0 rightarrow eta_{c2}(1D) K^0_S) times mathcal{B}(eta_{c2}(1D) to h_c gamma) < 3.5 times 10^{-5}$$, $$mathcal{B}(B^0 rightarrow eta_{c2}(1D) pi^- K^+) times mathcal{B}(eta_{c2}(1D) to h_c gamma) < 1.0 times 10^{-4}$$, and $$mathcal{B}(B^+ rightarrow eta_{c2}(1D) pi^+ K^0_S) times mathcal{B}(eta_{c2}(1D) to h_c gamma) < 1.1 times 10^{-4}$$ at 90% C. L. The analysis is based on the 711 $$mathrm{fb}^{-1}$$ data sample collected on the $$Upsilon(4S)$$ resonance by the Belle detector, which operated at the KEKB asymmetric-energy $$e^+ e^-$$ collider.

論文

Observation of $$tau^- rightarrow pi^- nu_{tau} e^+ e^- $$ and search for $$tau^- rightarrow pi^- nu_{tau} mu^+ mu^-$$

Jin, Y.*; 谷田 聖; Belle Collaboration*; 他198名*

Physical Review D, 100(7), p.071101_1 - 071101_9, 2019/10

https://doi.org/10.1103/PhysRevD.100.071101
 被引用回数：3 パーセンタイル：21.48(Astronomy & Astrophysics)

We present the first measurements of branching fractions of rare tau-lepton decays, $$tau^- rightarrow pi^- nu_{tau} ell^+ ell^-$$ ($$ell = e$$ or $$mu$$), using a data sample corresponding to 562 fb$$^{-1}$$ collected at a center-of-mass energy of 10.58 GeV with the Belle detector at the KEKB asymmetric-energy $$e^+ e^-$$ collider. The $$tau^- rightarrow pi^- nu_tau e^+ e^-$$ decay is observed for the first time with 7.0$$sigma$$ significance. The partial branching fraction determined by the structure-dependent mechanisms mediated by either a vector or an axial-vector current for the mass region $$M_{pi e e} > 1.05$$ GeV/$$c^2$$ is measured to be $$mathcal{B}(tau^-rightarrow pi^- nu_tau e^+ e^-)[M_{pi^- e^+ e^-} > 1.05~{rm GeV}/c^2] = (5.90 pm 0.53 pm 0.85 pm 0.11) times 10^{-6}$$, where the first uncertainty is statistical, the second is systematic, and the third is due to the model dependence. In the full phase space, due to the different detection efficiencies for the structure-dependent mechanisms mediated by axial-vector and vector currents, the branching fraction varies from $$mathcal{B}_{A}(tau^-rightarrow pi^- nu_tau e^+ e^-) = (1.46 pm 0.13 pm 0.21) times 10^{-5}$$ to $$mathcal{B}_{V}(tau^-rightarrow pi^- nu_tau e^+ e^-) = (3.01 pm 0.27 pm 0.43) times 10^{-5}$$, respectively. An upper limit is set on the branching fraction of the $$tau^- rightarrow pi^- nu_tau mu^+ mu^-$$ decay, $$mathcal{B}(tau^-rightarrow pi^- nu_tau mu^+ mu^-) < 1.14 times 10^{-5}$$, at the 90% confidence level.

論文

First measurements of absolute branching fractions of the $$Xi_c^+$$ baryon at Belle

Li, Y. B.*; 谷田 聖; Belle Collaboration*; 他194名*

Physical Review D, 100(3), p.031101_1 - 031101_8, 2019/08

https://doi.org/10.1103/PhysRevD.100.031101
 被引用回数：21 パーセンタイル：77.73(Astronomy & Astrophysics)

We present the first measurements of the absolute branching fractions of $$Xi_c^+$$ decays into $$Xi^- pi^+ pi^+$$ and $$p K^- pi^+$$ final states. Our analysis is based on a data set of $$(772pm 11)times 10^{6}$$ $$Bbar{B}$$ pairs collected at the $$Upsilon(4S)$$ resonance with the Belle detector at the KEKB $$e^+e^-$$ collider. We measure the absolute branching fraction of $$bar{B}^{0} to bar{Lambda}_{c}^{-} Xi_{c}^{+}$$ with the $$Xi_c^+$$ recoiling against $$bar{Lambda}_c^-$$ in $$bar{B}^0$$ decays resulting in $${cal B}(bar{B}^{0} to bar{Lambda}_{c}^{-} Xi_{c}^{+}) = [1.16 pm 0.42(rm stat.) pm 0.15(rm syst.)] times 10^{-3}$$. We then measure the product branching fractions $${cal B}(bar{B}^{0} to bar{Lambda}_c^- Xi_c^+){cal B}(Xi_c^+ to Xi^- pi^+ pi^+)$$ and $${cal B}(bar{B}^{0} to bar{Lambda}_c^- Xi_c^+){cal B}(Xi_c^+ to p K^- pi^+)$$. Dividing these product branching fractions by $$bar{B}^{0} to bar{Lambda}_{c}^{-} Xi_{c}^{+}$$ yields: $${cal B}(Xi_c^+ to Xi^- pi^+ pi^+) = [2.86 pm 1.21(rm stat.) pm 0.38(rm syst.)]%$$ and $${cal B}(Xi_c^+ to p K^- pi^+)=[0.45 pm 0.21(rm stat.) pm 0.07(rm syst.)]%$$. Our result for $${cal B}(Xi_c^+ to Xi^- pi^+ pi^+)$$ can be combined with $$Xi_c^+$$ branching fractions measured relative to $$Xi_c^+ to Xi^- pi^+ pi^+$$ to set the absolute scale for many $$Xi_c^+$$ branching fractions.

論文

Search for $$Omega(2012)to KXi(1530) to KpiXi$$ at Belle

Jia, S.*; 谷田 聖; Belle Collaboration*; 他193名*

Physical Review D, 100(3), p.032006_1 - 032006_11, 2019/08

https://doi.org/10.1103/PhysRevD.100.032006
 被引用回数：18 パーセンタイル：73.4(Astronomy & Astrophysics)

Using data samples of $$e^+e^-$$ collisions collected at the $$Upsilon(1S)$$, $$Upsilon(2S)$$, and $$Upsilon(3S)$$ resonances with the Belle detector, we search for the three-body decay of the $$Omega(2012)$$ baryon to $$KpiXi$$. This decay is predicted to dominate for models describing the $$Omega(2012)$$ as a $$KXi(1530)$$ molecule. No significant $$Omega(2012)$$ signals are observed in the studied channels, and 90% credibility level upper limits on the ratios of the branching fractions relative to $$K Xi$$ decay modes are obtained.

論文

Search for $$B^0 to X(3872) gamma$$

Chou, P.-C.*; 谷田 聖; Belle Collaboration*; 他192名*

Physical Review D, 100(1), p.012002_1 - 012002_8, 2019/07

https://doi.org/10.1103/PhysRevD.100.012002
 被引用回数：1 パーセンタイル：8.09(Astronomy & Astrophysics)

We report the results of a search for the decay $$B^0 to X(3872)(to J/psi pi^+ pi^-) gamma$$. The analysis is performed on a data sample corresponding to an integrated luminosity of $$711,{rm fb}^{-1}$$ and containing $$772 times 10^6 Bbar{B}$$ pairs, collected with the Belle detector at the KEKB asymmetric-energy $$e^+ e^-$$ collider running at the $$Upsilon(4S)$$ resonance energy. We find no evidence for a signal and place an upper limit of $$mathcal{B}(B^0 to X(3872)gamma)times mathcal{B}(X(3872) to J/psi pi^+ pi^-) < 5.1 times 10^{-7}$$ at 90% confidence level.

論文

Search for $$X(3872)$$ and $$X(3915)$$ decay into $$chi_{c1} pi^0$$ in $$B$$ decays at Belle

Bhardwaj, V.*; 谷田 聖; Belle Collaboration*; 他191名*

Physical Review D, 99(11), p.111101_1 - 111101_8, 2019/06

https://doi.org/10.1103/PhysRevD.99.111101
 被引用回数：6 パーセンタイル：38.22(Astronomy & Astrophysics)

We report a search for $$X(3872)$$ and $$X(3915)$$ in $$B^+ to chi_{c1} pi^0 K^+$$ decays. We set an upper limit of $$mathcal{B}(B^+ to X(3872) K^+) times mathcal{B}(X(3872) to chi_{c1} pi^0)$$ $$ < 8.1 times 10^{-6}$$ and $$mathcal{B}(B^+ to X(3915) K^+) times mathcal{B}(X(3915) to chi_{c1} pi^0)$$ $$ < 3.8 times 10^{-5}$$ at 90% confidence level. We also measure $$mathcal{B}(X(3872) to chi_{c1} pi^0)/mathcal{B}(X(3872) to J/psi pi^+ pi^-) < 0.97$$ at 90% confidence level. The results reported here are obtained from $$772 times 10^{6}$$ $$Boverline{B}$$ events collected at the $$Upsilon(4S)$$ resonance with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider.

論文

Measurements of branching fraction and direct $$CP$$ asymmetry in $$B^{pm}to K^{0}_{S}K^{0}_{S}K^{pm}$$ and a search for $$B^{pm}to K^{0}_{S}K^{0}_{S}pi^{pm}$$

Kaliyar, A. B.*; 谷田 聖; Belle Collaboration*; 他197名*

Physical Review D, 99(3), p.031102_1 - 031102_9, 2019/02

AA2019-0538.pdf:0.36MB

https://doi.org/10.1103/PhysRevD.99.031102
 被引用回数：1 パーセンタイル：14.65(Astronomy & Astrophysics)

We study charmless hadronic decays of charged $$B$$ mesons to the final states $$K^{0}_{S}K^{0}_{S}K^{pm}$$ and $$K^{0}_{S}K^{0}_{S}pi^{pm}$$ using a $$711 fb^{-1}$$ data sample that contains $$772times 10^6$$ $$Bbar{B}$$ pairs, and was collected at the $$Upsilon(4S)$$ resonance with the Belle detector at the KEKB asymmetric-energy $$e^{+}e^{-}$$ collider. For $$B^{pm}to K^{0}_{S}K^{0}_{S}K^{pm}$$, the measured branching fraction and direct $$CP$$ asymmetry are $$[10.42pm0.43(stat)pm 0.22(syst)]times10^{-6}$$ and [$$+1.6pm3.9(stat)pm 0.9(syst)$$]%, respectively. In the absence of a statistically significant signal for $$B^{pm}to K^{0}_{S}K^{0}_{S}pi^{pm}$$, we obtain a 90% confidence-level upper limit on its branching fraction as $$8.7 times10^{-7}$$.

論文

Search for a light $$CP$$-odd Higgs boson and low-mass dark matter at the Belle experiment

Seong, I. S.*; 谷田 聖; Belle Collaboration*; 他191名*

Physical Review Letters, 122(1), p.011801_1 - 011801_8, 2019/01

AA2019-0529.pdf:0.35MB

https://doi.org/10.1103/PhysRevLett.122.011801
 被引用回数：16 パーセンタイル：76.31(Physics, Multidisciplinary)

We report on the first Belle search for a light $$CP$$-odd Higgs boson, $$A^{0}$$, that decays into low mass dark matter, $$chi$$, in final states with a single photon and missing energy. We search for events produced via the dipion transition $$Upsilon(textrm{2S})rightarrowUpsilon(textrm{1S})pi^{+}pi^{-}$$, followed by the on-shell process $$Upsilon(textrm{1S})rightarrowgamma A^{0}$$ with $$A^{0} rightarrowchichi$$, or by the off-shell process $$Upsilon(textrm{1S})rightarrowgammachichi$$. Utilizing a data sample of 157.3 $$times$$ 10$$^{6}$$ $$Upsilon(textrm{2S})$$ decays, we find no evidence for a signal. We set limits on the branching fractions of such processes in the mass ranges $$M_{A^{0}} < 8.97$$ GeV/$$c^2$$ and $$M_{chi} < 4.44$$ GeV/$$c^2$$. We then use the limits on the off-shell process to set competitive limits on WIMP-nucleon scattering in the WIMP mass range below 5 GeV/$$c^2$$.

論文

Measurement of the decays $$Lambda_cto Sigmapipi$$ at Belle

Berger, M.*; 谷田 聖; Belle Collaboration*; 他197名*

Physical Review D, 98(11), p.112006_1 - 112006_10, 2018/12

AA2018-0765.pdf:0.74MB

https://doi.org/10.1103/PhysRevD.98.112006
 被引用回数：5 パーセンタイル：29.53(Astronomy & Astrophysics)

We report measurements of the branching fractions of the decays $$Lambda^+_ctoSigma^+pi^-pi^+$$, $$Lambda^+_ctoSigma^0pi^+pi^0$$ and $$Lambda^+_ctoSigma^+pi^0pi^0$$ relative to the reference channel $$Lambda^+_cto pK^-pi^+$$. The analysis is based on the full data sample collected at and close to $$Upsilon(4S)$$ resonance by the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider corresponding to the integrated luminosity of 711 fb$$^{-1}$$. We measure $${cal B}(Lambda^+_crightarrowSigma^+pi^-pi^+)/{cal B}(Lambda^+_cto pK^-pi^+) = 0.706~pm 0.003~pm 0.029$$, $${cal B}(Lambda^+_crightarrowSigma^0pi^+pi^0)/{cal B}(Lambda^+_cto pK^-pi^+) = 0.491~pm 0.005~pm 0.028$$ and $${cal B}(Lambda^+_crightarrowSigma^+pi^0pi^0)/{cal B}(Lambda^+_cto pK^-pi^+) = 0.198~pm 0.006~pm 0.016$$. The listed uncertainties are statistical and systematic, respectively.

論文

Observation of $$Upsilon(2S)togamma eta_{b}(1S)$$ decay

Fulsom, B. G.*; 谷田 聖; Belle Collaboration*; 他197名*

Physical Review Letters, 121(23), p.232001_1 - 232001_8, 2018/12

AA2018-0717.pdf:0.36MB

https://doi.org/10.1103/PhysRevLett.121.232001
 被引用回数：5 パーセンタイル：42.95(Physics, Multidisciplinary)

We report the observation of $$Upsilon(2S)togammaeta_{b}(1S)$$ decay based on analysis of the inclusive photon spectrum of $$24.7$$ fb$$^{-1}$$ of $$e^+ e^-$$ collisions at the $$Upsilon(2S)$$ center-of-mass energy collected with the Belle detector at the KEKB asymmetric-energy $$e^+ e^-$$ collider. We measure a branching fraction of $$mathcal{B}(Upsilon(2S)togammaeta_{b}(1S))=(6.1^{+0.6+0.9}_{-0.7-0.5})times 10^{-4}$$, and derive an $$eta_{b}(1S)$$ mass of $$9394.8^{+2.7+4.5}_{-3.1-2.7}$$ MeV/$$c^{2}$$, where the uncertainties are statistical and systematic, respectively. The significance of our measurement is greater than 7 standard deviations, constituting the first observation of this decay mode.

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