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論文

Persistence of collectivity in the low-lying states of $$^{30,31}$$Na inside the $$N=20$$ island of inversion

Salinas, R.*; 岩崎 弘典*; 宇都野 穣; 他18名*

Physical Review C, 113(1), p.014330_1 - 014330_9, 2026/01

https://doi.org/10.1103/zp75-1ctq
 被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)

中性子過剰核では中性子数20の魔法数が消滅していることが知られているが、それを特徴づける物理量が核変形に直接関係する$$B(E2)$$値である。この研究では、ミシガン州立大学のサイクロトロンにて$$^{30,31}$$Naのクーロン励起によってこれらの原子核の基底状態バンド間の$$B(E2)$$値を測定した。$$^{30}$$Naについては$$3^+$$と$$4^+$$、$$^{31}$$Naについては$$5/2^+$$と$$7/2^+$$のそれぞれ2本の励起状態への$$B(E2)$$値が得られ、大きな固有四重極モーメントをもった変形核であることが確かめられた。これらの実験値は殻模型による計算値ともよい一致を示している。

論文

Control of spin currents by magnon interference in a canted antiferromagnet

Sheng, L.*; 山本 慧; 他18名*

Nature Physics, 21(5), p.740 - 745, 2025/05

https://doi.org/10.1038/s41567-025-02819-7
 被引用回数：17 パーセンタイル：98.03(Physics, Multidisciplinary)

Controlling the spin current lies at the heart of spintronics and its applications. In ferromagnets, the sign of spin currents is fixed once the current direction is determined. However, spin currents in antiferromagnets can possess opposite polarizations, but this requires enormous magnetic fields to lift the degeneracy between the two modes. Therefore, controlling spin currents with opposite polarization is still a challenge. Here we demonstrate the control of spin currents at room temperature by magnon interference in a canted antiferromagnet, namely, haematite that has recently been classified as an altermagnet. Magneto-optical characterization by Brillouin light scattering reveals that the spatial periodicity of the beating patterns is tunable via the microwave frequency. We further observe that the inverse spin Hall voltage changes sign as the frequency is tuned, evincing a frequency-controlled switching of polarization of pure spin currents. Our work highlights the use of antiferromagnetic magnon interference to control spin currents, which substantially extends the horizon for the emerging field of coherent antiferromagnetic spintronics.

論文

Discovery of new isotope $$^{241}$$U and systematic high-precision atomic mass measurements of neutron-rich Pa-Pu nuclei produced via multinucleon transfer reactions

庭瀬 暁隆*; 伊藤 由太; 他18名*

Physical Review Letters, 130(13), p.132502_1 - 132502_6, 2023/03

https://doi.org/10.1103/PhysRevLett.130.132502
 被引用回数：60 パーセンタイル：98.16(Physics, Multidisciplinary)

新同位体$$^{241}$$Uを合成し、KISS施設の$$^{238}$$U+$$^{198}$$Pt系の多核子移行反応において、19種類の中性子過剰Pa-Pu同位体の系統的原子量測定が行われた。本実験結果は、この領域の核種において、$$N=152$$シェルギャップに向かう未踏の中性子過剰アクチニド同位体へのアクセスに多核子移行反応が重要な役割を果たすことを実証した。

論文

First search for the weak radiative decays $$Lambda_c^+ to Sigma^+ gamma$$ and $$Xi_c^0 to Xi^0 gamma$$

Li, Y.*; 谷田 聖; Belle Collaboration*; 他187名*

Physical Review D, 107(3), p.032001_1 - 032001_11, 2023/02

https://doi.org/10.1103/PhysRevD.107.032001
 被引用回数：3 パーセンタイル：28.99(Astronomy & Astrophysics)

We present the first search for the weak radiative decays $$Lambda_c^+ to Sigma^+ gamma$$ and $$Xi_c^0 to Xi^0 gamma$$ using a data sample of 980~fb$$^{-1}$$ collected by the Belle detector operating at the KEKB asymmetric-energy $$e^+e^-$$ collider. There are no evident $$Lambda_c^+ to Sigma^+ gamma$$ or $$Xi_c^0 to Xi^0 gamma$$ signals. Taking the decays $$Lambda_c^+ to p K^- pi^+$$ and $$Xi_c^0 to Xi^- pi^+$$ as normalization channels, the upper limits at 90% credibility level on the ratios of branching fractions $${cal B}(Lambda_c^+ to Sigma^+ gamma)/{cal B}(Lambda_c^+ to p K^{-} pi^+) < 4.0 times 10^{-3}$$ and $${cal B}(Xi_c^0 to Xi^0 gamma)/{cal B}(Xi_c^0 to Xi^- pi^+) < 1.2 times 10^{-2}$$ are determined. We obtain the upper limits at 90% credibility level on the absolute branching fractions $${cal B}(Lambda_c^+ to Sigma^+ gamma) < 2.6 times 10^{-4}$$ and $${cal B}(Xi_c^0 to Xi^0 gamma) < 1.8 times 10^{-4}$$.

論文

High accuracy, high resolution $$^{235}$$U(n,f) cross section from n_TOF (CERN) from 18 meV to 10 keV

Mastromarco, M.*; Amaducci, S.*; Colonna, N.*; 木村 敦; 他118名*

European Physical Journal A, 58(8), p.147_1 - 147_13, 2022/08

https://doi.org/10.1140/epja/s10050-022-00779-7
 被引用回数：7 パーセンタイル：61.75(Physics, Nuclear)

The $$^{235}$$U(n,f) cross section was measured in a wide energy range (18 meV - 170 keV) at the n_TOF facility at CERN, relative to $$^6$$Li(n,t) and $$^{10}$$B(n,$$alpha$$) standard reactions, with a setup based on a stack of six samples and six silicon detectors placed in the neutron beam. A resonance analysis has been performed up to 200 eV, with the code SAMMY. A good agreement, within 0.5%, is found on average between the new results and the latest evaluated data files ENDF/B-VIII.0 and JEFF-3.3, as well as with respect to the broad group average fission cross section established in the framework of the standard working group of IAEA. However, some discrepancies, of up to 4%, are still present in some specific energy regions.

論文

An Improved search for the electric dipole moment of the $$tau$$ lepton

居波 賢二*; 谷田 聖; Belle Collaboration*; 他186名*

Journal of High Energy Physics (Internet), 2022(4), p.110_1 - 110_13, 2022/04

https://doi.org/10.1007/JHEP04(2022)110
 被引用回数：25 パーセンタイル：84.58(Physics, Particles & Fields)

We report a measurement of the electric dipole moment of the $$tau$$ lepton ($$d_tau$$) using an 833~fb$$^{-1}$$ data sample collected near the $$Upsilon(4S)$$ resonance, with the Belle detector at the KEKB asymmetric-energy $$e^+ e^-$$ collider. Using an optimal observable method, we obtain the real and imaginary parts of $$d_tau$$ as $${rm Re}(d_tau) = (-0.62 pm 0.63) times 10^{-17} ~e{rm cm}$$ and $${rm Im}(d_tau) = (-0.40 pm 0.32) times 10^{-17} ~e{rm cm}$$, respectively. These results are consistent with null electric dipole moment at the present level of experimental sensitivity and improve the sensitivity by about a factor of three.

論文

Search for the decay $$B_s^0rightarrowetaeta$$

Bhuyan, B.*; 谷田 聖; Belle Collaboration*; 他185名*

Physical Review D, 105(1), p.012007_1 - 012007_7, 2022/01

https://doi.org/10.1103/PhysRevD.105.012007
 被引用回数：2 パーセンタイル：15.64(Astronomy & Astrophysics)

We report results from a search for the decay $$B_s^0rightarrowetaeta$$ using 121.4 fb$$^{-1}$$ of data collected at the $$Upsilon(5S)$$ resonance with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider. We do not observe any signal and set an upper limit on the branching fraction of $$14.3times 10^{-5}$$ at $$90%$$ confidence level. This result represents a significant improvement over the previous most stringent limit.

論文

Study of $$e^+e^-to Upsilon(rm1S,2S)eta$$ and $$e^+e^-to Upsilon(rm 1S)eta^{prime}$$ at $$sqrt{s}=10.866$$ GeV with the Belle detector

Kovalenko, E.*; 谷田 聖; Belle Collaboration*; 他181名*

Physical Review D, 104(11), p.112006_1 - 112006_12, 2021/12

AA2022-0160.pdf:0.91MB

https://doi.org/10.1103/PhysRevD.104.112006
 被引用回数：1 パーセンタイル：0.00(Astronomy & Astrophysics)

We report the first observation of the processes $$e^+e^-toUpsilon(rm 1S,2S)eta$$ at $$sqrt{s}$$=10.866 GeV with a $$10.2sigma$$ and $$16.5sigma$$ significance respectively. The measured Born cross sections are $$sigma(e^+e^- to Upsilon(2S)eta)=2.07 pm 0.21 pm 0.19$$ pb, and $$sigma(e^+e^- to Upsilon(rm 1S)eta)=0.42 pm 0.08 pm 0.04$$ pb. We also set the upper limit on the cross section of the process $$e^+e^- to Upsilon(rm 1S)eta^{prime}$$ to be $$sigma(e^+e^- to Upsilon(rm 1S)eta^{prime}) < 0.035$$~pb at $$90%$$ CL. The results are obtained with the data sample collected with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider in the energy range from 10.63 GeV to 11.02 GeV.

論文

Search for lepton-flavor-violating tau-lepton decays to $$ellgamma$$ at Belle

宇野 健太*; 谷田 聖; Belle Collaboration*; 他181名*

Journal of High Energy Physics (Internet), 2021(10), p.19_1 - 19_12, 2021/10

https://doi.org/10.1007/JHEP10(2021)019
 被引用回数：42 パーセンタイル：88.40(Physics, Particles & Fields)

Charged lepton flavor violation is forbidden in the Standard Model but possible in several new physics scenarios. In many of these models, the radiative decays $$tau^{pm}rightarrowell^{pm}gamma$$ ($$ell=e,mu$$) are predicted to have a sizeable probability, making them particularly interesting channels to search at various experiments. An updated search via $$tau^{pm}rightarrowell^{pm}gamma$$ using full data of the Belle experiment, corresponding to an integrated luminosity of 988 fb$$^{-1}$$, is reported for charged lepton flavor violation. No significant excess over background predictions from the Standard Model is observed, and the upper limits on the branching fractions, $$mathcal{B}(tau^{pm}rightarrow mu^{pm}gamma)$$ $$leq$$ $$4.2times10^{-8}$$ and $$mathcal{B}(tau^{pm}rightarrow e^{pm}gamma)$$ $$leq$$ $$5.6times10^{-8}$$, are set at 90% confidence level.

論文

Unveiling unconventional magnetism at the surface of Sr$$_2$$RuO$$_4$$

Fittipaldi, R.*; Hartmann, R.*; Mercaldo, M. T.*; 小森 祥央*; Bj${o}$rlig, A.*; 髭本 亘; 前野 悦輝*; Di Bernardo, A.*; 他18名*

Nature Communications (Internet), 12, p.5792_1 - 5792_9, 2021/10

https://doi.org/10.1038/s41467-021-26020-5
 被引用回数：31 パーセンタイル：76.86(Multidisciplinary Sciences)

層状酸化物ペロブスカイト構造を持つSr$$_2$$RuO$$_4$$の超伝導は長年にわたり議論がなされており、その理解のために背景となる常伝導状態の振る舞いは極めて重要となる。本研究では低エネルギーミュオンを用いることで、表面における磁性の存在を見出した。この磁性は50Kよりも高い温度から見られており、他の物質の状態とも深い関連があるものと考えられる。

論文

Measurement of branching fractions and search for $$CP$$ violation in $$D^{0}topi^{+}pi^{-}eta$$, $$D^{0}to K^{+}K^{-}eta$$, and $$D^{0}tophieta$$ at Belle

Li, L. K.*; 谷田 聖; Belle Collaboration*; 他187名*

Journal of High Energy Physics (Internet), 2021(9), p.75_1 - 75_21, 2021/09

https://doi.org/10.1007/JHEP09(2021)075
 被引用回数：5 パーセンタイル：27.76(Physics, Particles & Fields)

We measure the branching fractions and $$CP$$ asymmetries for the singly Cabibbo-suppressed decays $$D^{0}topi^{+}pi^{-}eta$$, $$D^{0}to K^{+}K^{-}eta$$, and $$D^{0}tophieta$$, using 980 fb$$^{-1}$$ of data from the Belle experiment at the KEKB $$e^+e^-$$ collider. We obtain $$mathcal{B}(D^{0}topi^{+}pi^{-}eta) = [1.22pm 0.02,({rm stat})pm 0.02,({rm syst})pm 0.03,(mathcal{B}_{rm ref})]times 10^{-3},, mathcal{B}(D^{0}to K^{+}K^{-}eta) = [1.80,^{+0.07}_{-0.06},({rm stat})pm 0.04,({rm syst})pm 0.05,(mathcal{B}_{rm ref})]times 10^{-4},, mathcal{B}(D^{0}tophieta) = [1.84pm 0.09,({rm stat})pm 0.06,({rm syst})pm 0.05,(mathcal{B}_{rm ref})]times 10^{-4},, $$ where the third uncertainty ($$mathcal{B}_{rm ref}$$) is from the uncertainty in the branching fraction of the reference mode $$D^{0} to K^{-}pi^{+}eta$$. The color-suppressed decay $$D^{0}tophieta$$ is observed for the first time, with very high significance. The results for the $$CP$$ asymmetries are $$A_{CP}(D^{0}topi^{+}pi^{-}eta) = [0.9pm 1.2,({rm stat})pm 0.5,({rm syst})]%,, A_{CP}(D^{0}to K^{+}K^{-}eta) = [-1.4pm 3.3,({rm stat})pm 1.1,({rm syst})]%,, A_{CP}(D^{0}tophieta) = [-1.9pm 4.4,({rm stat})pm 0.6,({rm syst})]%,. $$ The results for $$D^{0}topi^{+}pi^{-}eta$$ are a significant improvement over previous results. The branching fraction and $$A_{CP}$$ results for $$D^{0}to K^{+}K^{-}eta$$, and the $$A_{CP}$$ result for $$D^{0}tophieta$$, are the first such measurements. No evidence for $$CP$$ violation is found in any of these decays.

論文

Measurements of the branching fractions of the semileptonic decays $$Xi_{c}^{0} to Xi^{-} ell^{+} nu_{ell}$$ and the asymmetry parameter of $$Xi_{c}^{0} to Xi^{-} pi^{+}$$

Li, Y. B.*; 谷田 聖; Belle Collaboration*; 他182名*

Physical Review Letters, 127(12), p.121803_1 - 121803_8, 2021/09

https://doi.org/10.1103/PhysRevLett.127.121803
 被引用回数：37 パーセンタイル：88.63(Physics, Multidisciplinary)

Using data samples of 89.5 and 711 fb$$^{-1}$$ recorded at energies of $$sqrt{s}=10.52$$ and $$10.58$$ GeV, respectively, with the Belle detector at the KEKB $$e^+e^-$$ collider, we report measurements of branching fractions of semileptonic decays $$Xi_{c}^{0} to Xi^{-} ell^{+} nu_{ell}$$ ($$ell=e$$ or $$mu$$) and the $$CP$$-asymmetry parameter of $$Xi_{c}^{0} to Xi^{-} pi^{+}$$ decay. The branching fractions are measured to be $${cal B}(Xi_{c}^{0} to Xi^{-} e^{+} nu_{e}$$)=($$1.31 pm 0.04 pm 0.07 pm 0.38$$)% and $${cal B}(Xi_{c}^{0} to Xi^{-} mu^{+} nu_{mu}$$)=($$1.27 pm 0.06 pm 0.10 pm 0.37$$)%, and the decay parameter $$alpha_{Xipi}$$ is measured to be $$0.63 pm 0.03 pm 0.01$$ with much improved precision compared to the current world average. The corresponding ratio $${cal B}(Xi_{c}^{0} to Xi^{-} e^{+} nu_{e})$$/$${cal B}(Xi_{c}^{0} to Xi^{-} mu^{+} nu_{mu})$$ is 1.03 $$pm$$ 0.05 $$pm$$ 0.07, which is consistent with the expectation of lepton flavor universality. The first measured asymmetry parameter $${cal A}_{CP} = (alpha_{Xi^{-}pi^{+}} + alpha_{bar{Xi}^{+}pi^{-}})/(alpha_{Xi^{-}pi^{+}} - alpha_{bar{Xi}^{+}pi^{-}}) = 0.024 pm 0.052 pm 0.014$$ is found to be consistent with zero. The first and the second uncertainties above are statistical and systematic, respectively, while the third ones arise due to the uncertainty of the $$Xi_{c}^{0} to Xi^{-} pi^+$$ branching fraction.

論文

Measurements of branching fractions and asymmetry parameters of $$Xi^0_cto Lambdabar K^{*0}$$, $$Xi^0_cto Sigma^0bar K^{*0}$$, and $$Xi^0_cto Sigma^+K^{*-}$$ decays at Belle

Jia, S.*; 谷田 聖; Belle Collaboration*; 他186名*

Journal of High Energy Physics (Internet), 2021(6), p.160_1 - 160_13, 2021/06

https://doi.org/10.1007/JHEP06(2021)160
 被引用回数：5 パーセンタイル：27.76(Physics, Particles & Fields)

Using a data sample of 980 fb$$^{-1}$$ collected with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider, we study the processes of $$Xi^0_cto Lambdabar K^{*0}$$, $$Xi^0_cto Sigma^0bar K^{*0}$$, and $$Xi^0_cto Sigma^+K^{*-}$$ for the first time. The relative branching ratios to the normalization mode of $$Xi^0_c to Xi^- pi^+$$ are measured to be $${cal B}(Xi^0_cto Lambdabar K^{*0})/{cal B}(Xi_c^0 to Xi^-pi^+)=0.18 pm 0.02({rm stat.})pm0.01({rm syst.}),$$ $${cal B}(Xi^0_cto Sigma^0bar K^{*0})/{cal B}(Xi_c^0to Xi^-pi^+)=0.69pm0.03({rm stat.})pm0.03({rm syst.}),$$ $${cal B}(Xi^0_cto Sigma^+K^{*-})/{cal B}(Xi_c^0to Xi^-pi^+)=0.34pm0.06({rm stat.})pm0.02({rm syst.}),$$ where the uncertainties are statistical and systematic, respectively. We obtain the branching fractions of $$Xi^0_cto Lambdabar K^{*0}$$, $$Xi^0_cto Sigma^0bar K^{*0}$$, and $$Xi^0_cto Sigma^+K^{*-}$$ to be $${cal B}(Xi^0_cto Lambdabar K^{*0})=(3.3pm0.3({rm stat.})pm0.2({rm syst.})pm1.0({rm ref.}))times10^{-3},$$ $${cal B}(Xi^0_cto Sigma^0bar K^{*0})=(12.4pm0.5({rm stat.})pm0.5({rm syst.})pm3.6({rm ref.}))times10^{-3},$$ $${cal B}(Xi^0_cto Sigma^+K^{*-})=(6.1pm1.0({rm stat.})pm0.4({rm syst.})pm1.8({rm ref.}))times10^{-3},$$ where the uncertainties are statistical, systematic, and from $${cal B}(Xi_c^0 to Xi^-pi^+)$$, respectively. The asymmetry parameters $$alpha(Xi^0_cto Lambdabar K^{*0})$$ and $$alpha(Xi^0_cto Sigma^+K^{*-})$$ are $$0.15pm0.22({rm stat.})pm0.04({rm syst.})$$ and $$-0.52pm0.30({rm stat.})pm0.02({rm syst.})$$, respectively, where the uncertainties are statistical followed by systematic.

論文

Measurement of the energy dependence of the $$e^+e^-to Bbar{B}$$, $$Bbar{B}^*$$ and $$B^*bar{B}^*$$ exclusive cross sections

Mizuk, R.*; 谷田 聖; Belle Collaboration*; 他188名*

Journal of High Energy Physics (Internet), 2021(6), p.137_1 - 137_35, 2021/06

https://doi.org/10.1007/JHEP06(2021)137
 被引用回数：21 パーセンタイル：70.62(Physics, Particles & Fields)

We report the first measurement of the exclusive cross sections $$e^+e^-to Bbar{B}$$, $$e^+e^-to Bbar{B}^*$$, and $$e^+e^-to B^*bar{B}^*$$ in the energy range from 10.63 GeV to 11.02 GeV. The $$B$$ mesons are fully reconstructed in a large number of hadronic final states and the three channels are identified using a beam-constrained-mass variable. The shapes of the exclusive cross sections show oscillatory behavior with several maxima and minima. The results are obtained using data collected by the Belle experiment at the KEKB asymmetric-energy $$e^+e^-$$ collider.

論文

Measurement of branching fraction and search for $$CP$$ violation in $$Bto phi phi K$$

Mohanty, S.*; 谷田 聖; Belle Collaboration*; 他184名*

Physical Review D, 103(5), p.052013_1 - 052013_9, 2021/03

AA2022-0152.pdf:0.6MB

https://doi.org/10.1103/PhysRevD.103.052013
 被引用回数：0 パーセンタイル：0.00(Astronomy & Astrophysics)

We report the measurement of branching fractions and $$CP$$-violation asymmetries in $$Bto phi phi K$$ decays based on a $$711,{rm fb}^{-1}$$ data sample containing $$772times 10^6$$ $$Bbar{B}$$ events. The data were recorded at the $$Upsilon (4S)$$ resonance with the Belle detector at the KEKB asymmetric-energy $$e^+ e^-$$ collider. For $$B^+ to phi phi K^+$$, the branching fraction and $$CP$$-violation asymmetry measured below the $$eta_{c}$$ threshold ($$m_{phiphi} < 2.85,{rm GeV}/c^2$$) are $$[3.43^{,+,0.48}_{,-,0.46}({rm stat})pm 0.22({rm syst})] times10^{-6}$$ and $$-0.02pm0.11({rm stat})pm0.01({rm syst})$$, respectively. Similarly, the branching fraction obtained for $$B^0 tophiphi K^0$$ below the $$eta_{c}$$ threshold is $$[3.02^{,+,0.75}_{,-,0.66} ({rm stat})pm ,0.20({rm syst})]times10^{-6}$$. We also measure the $$CP$$-violation asymmetry for $$B^+ tophiphi K^+$$ within the $$eta_{c}$$ region ($$m_{phiphi}in [2.94,3.02],{rm GeV}/c^2$$) to be $$+0.12pm0.12({rm stat})pm0.01({rm syst})$$.

論文

Measurement of the charm-mixing parameter $$y_{CP}$$ in $$D^{0}to K^{0}_{S}omega$$ decays at Belle

Nayak, M.*; 谷田 聖; Belle Collaboration*; 他180名*

Physical Review D, 102(7), p.071102_1 - 071102_8, 2020/10

https://doi.org/10.1103/PhysRevD.102.071102
 被引用回数：8 パーセンタイル：38.41(Astronomy & Astrophysics)

We report the first measurement of the charm-mixing parameter $$y_{CP}$$ in $$D^{0}$$ decays to the $$CP$$-odd final state $$K^{0}_{S}omega$$. The study uses the full Belle $$e^{+}e^-$$ annihilation data sample of $$976rm~ fb^{-1}$$ taken at or near the $$Upsilon(4S)$$ centre-of-mass energy. We find $$y_{CP} = (0.96 pm 0.91 pm 0.61 {}^{+0.17}_{-0.00})%$$, where the first uncertainty is statistical, the second is systematic due to event selection and background, and the last is due to possible presence of $$CP$$-even decays in the data sample.

論文

Dalitz analysis of $$D^{0}to K^{-}pi^{+}eta$$ decays at Belle

Chen, Y. Q.*; 谷田 聖; Belle Collaboration*; 他181名*

Physical Review D, 102(1), p.012002_1 - 012002_12, 2020/07

https://doi.org/10.1103/PhysRevD.102.012002
 被引用回数：19 パーセンタイル：66.06(Astronomy & Astrophysics)

We present the results of the first Dalitz plot analysis of the decay $$D^{0}to K^{-}pi^{+}eta$$. The analysis is performed on a data set corresponding to an integrated luminosity of 953 $$rm{fb}^{-1}$$ collected by the Belle detector at the asymmetric-energy $$e^{+}e^{-}$$ KEKB collider. The Dalitz plot is well described by a combination of the six resonant decay channels $$bar{K}^{*}(892)^0eta$$, $$K^{-}a_0(980)^+$$, $$K^{-}a_2(1320)^+$$, $$bar{K}^{*}(1410)^0eta$$, $$K^{*}(1680)^-pi^{+}$$ and $$K_2^{*}(1980)^-pi^{+}$$, together with $$Kpi$$ and $$Keta$$ S-wave components. The decays $$K^{*}(1680)^{-}to K^{-}eta$$ and $$K_{2}^{*}(1980)^{-}to K^{-}eta$$ are observed for the first time. We measure ratio of the branching fractions, $$frac{mathcal{B}(D^{0}to K^{-}pi^{+}eta)}{mathcal{B}(D^{0}to K^{-}pi^{+})}$$ =0.500 $$pm 0.002 {rm(stat)} pm0.020 {rm(syst)}pm 0.003 {rm (mathcal{B}_{PDG})}$$. Using the Dalitz fit result, the ratio $$frac{mathcal{B}(K^{*}(1680) to K eta)}{mathcal{B}(K^{*}(1680)to Kpi)}$$ is measured to be $$0.11 pm 0.02 {rm(stat)}^{+0.06}_{-0.04}{rm(syst)} pm 0.04{rm(mathcal{B}_{{PDG}})}$$; this is much lower than the theoretical expectations ($$approx 1$$) made under the assumption that $$K^{*}(1680)$$ is a pure $$1^{3}D_1$$ state. The product branching fraction $$mathcal{B}(D^0 to [K_2^{*}(1980)^- to K^{-} eta] pi^{+}) = (2.2^{+1.7}_{-1.9})times10^{-4}$$ is determined. In addition, the $$pieta^{prime}$$ contribution to the $$a_0(980)^{pm}$$ resonance shape is confirmed with 10.1$$sigma$$ statistical significance using the three-channel Flatte model. We also measure $$mathcal{B}(D^0tobar{K}^{*}(892)^0eta)=(1.41^{+0.13}_{-0.12})%$$. This is consistent with, and more precise than, the current world average $$(1.02pm0.30)%$$, deviates with a significance of more than $$3sigma$$ from the theoretical predictions of (0.51-0.92)%.

論文

Observation of a new structure near 10.75 GeV in the energy dependence of the $$e^{+}$$e$$^{-} to Upsilon(nS) pi^{+}pi^{-}$$ $$(n = 1, 2, 3)$$ cross sections

Mizuk, R.*; 谷田 聖; Belle Collaboration*; 他181名*

Journal of High Energy Physics (Internet), 2019(10), p.220_1 - 220_26, 2019/10

https://doi.org/10.1007/JHEP10(2019)220
 被引用回数：52 パーセンタイル：88.44(Physics, Particles & Fields)

We report a new measurement of the $$e^+e^-toUpsilon(nS)pi^+pi^-$$ ($$n=1,2,3$$) cross sections at energies from 10.52 to 11.02 GeV using data collected with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider. We observe a new structure in the energy dependence of the cross sections; if described by a Breit-Wigner function its mass and width are found to be $$M=(10752.7pm5.9,^{+0.7}_{-1.1}),$$MeV/$$c^2$$ and $$Gamma=(35.5^{+17.6}_{-11.3},^{+3.9}_{-3.3}),$$MeV, where the first error is statistical and the second is systematic. The global significance of the new structure that includes a systematic uncertainty is 6.7 standard deviations. We also find evidence for the $$e^+e^-toUpsilon(1S)pi^+pi^-$$ process at the energy 10.52 GeV, which is below the $$Bbar{B}$$ threshold.

論文

Measurement of the CKM matrix element $$|V_{cb}|$$ from $$B^0to D^{*-}ell^ {+} nu_ell$$ at Belle

Waheed, E.*; 谷田 聖; Belle Collaboration*; 他187名*

Physical Review D, 100(5), p.052007_1 - 052007_32, 2019/09

https://doi.org/10.1103/PhysRevD.100.052007
 被引用回数：58 パーセンタイル：90.65(Astronomy & Astrophysics)

We present a new measurement of the CKM matrix element $$|V_{cb}|$$ from $$ B^{0} rightarrow D^{*}ell nu$$ decays, reconstructed with full Belle data set ($$711 , rm fb^{-1}$$). Two form factor parameterisations, based on work by the CLN and BGL groups, are used to extract the product $$mathcal{F}(1)eta_{rm EW}|V_{cb}|$$ and the decay form factors, where $$mathcal{F}(1)$$ is the factor normalisation and $$eta_{rm EW}$$ is a small electroweak correction. In the CLN parameterisation we find $$mathcal{F}(1)eta_{rm EW}|V_{cb}| = (35.06 pm 0.15 pm 0.54) times 10^{-3}$$, $$rho^{2}=1.106 pm 0.031 pm 0.007$$, $$R_{1}(1)=1.229 pm 0.028 pm 0.009$$, $$R_{2}(1)=0.852 pm 0.021 pm 0.006$$. In the BGL parameterisation we find $$mathcal{F}(1)eta_{rm EW}|V_{cb}|= 38.73 pm 0.25 pm 0.60$$, which is higher but consistent with the determination from inclusive semileptonic $$B$$ decays when correcting for $$mathcal{F}(1)eta_{rm EW}$$. This is the most precise measurement of $$mathcal{F}(1)eta_{rm EW}|V_{cb}|$$ and form factors that has ever been carried out, and the first direct study of the BGL form factor parameterisation in an experimental measurement.

論文

Measurement of the $$^{235}$$U(n, f) cross section relative to the $$^{6}$$Li(n, t) and $$^{10}$$B(n, $$alpha$$) standards from thermal to 170 keV neutron energy range at n_TOF

Amaducci, S.*; 原田 秀郎; 木村 敦; 他118名*

European Physical Journal A, 55(7), p.120_1 - 120_19, 2019/07

https://doi.org/10.1140/epja/i2019-12802-7
 被引用回数：26 パーセンタイル：86.09(Physics, Nuclear)

n_TOF施設にて、熱から170keVの中性子エネルギー領域において、$$^{235}$$U(n, f)断面積を測定した。$$^{6}$$Li(n, t)および$$^{10}$$B(n, $$alpha$$)標準断面積に対する相対測定により、1.5%という系統的不確かさで測定値を得た。本測定には、6層からなるサンプルと6台のSi検出器を用いた。9$$sim$$18keVエネルギー領域において、本測定結果は、最近の評価済み核データであるENDF/B-VIII.0およびJEFF3.3の評価値が、約5%過大評価であることを示した。高分解能測定の結果、keV領域で、共鳴構造を観測した。本測定より、7.8$$sim$$11eVのエネルギー範囲の断面積の積分値について、249.7$$pm$$1.4(統計的不確かさ)$$pm$$0.94(系統的不確かさ)b$$times$$eVという結果を得た。この結果は、最近確立された標準値247.5$$pm$$3b$$times$$eVを支持するものである。

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