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Li, Y.*; 谷田 聖; Belle Collaboration*; 他190名*
Physical Review D, 104(5), p.052005_1 - 052005_9, 2021/09
被引用回数:9 パーセンタイル:65.5(Astronomy & Astrophysics)Using a data sample of 980~fb collected with the Belle detector operating at the KEKB asymmetric-energy collider, we present evidence for the in the resonant substructure of ( = + ) decays. The significance of the signal is 4.2 after considering the systematic uncertainties. The ratio of the branching fraction of relative to that of is calculated to be 0.220 0.059(stat.) 0.035(syst.). The individual ratios of the branching fractions of the two isospin modes are also determined, and found to be =(9.6 3.2(stat.) 1.8(syst.))% and = (5.5 2.8(stat.) 0.7(syst.))%.
Yelton, J.*; 谷田 聖; Belle Collaboration*; 他205名*
Physical Review D, 104(5), p.052003_1 - 052003_8, 2021/09
被引用回数:4 パーセンタイル:37.94(Astronomy & Astrophysics)Using 980 of data with the Belle detector operating at the KEKB asymmetric-energy collider, we report the measurements of the masses, and the first measurements of the instrinsic widths, of the and charmed baryons. We find , , , and , where the uncertainties are statistical and systematic, respectively. These measurements can be used to test models of the underlying quark structure of the states.
Jia, S.*; 谷田 聖; Belle Collaboration*; 他200名*
Physical Review D, 104(1), p.012012_1 - 012012_9, 2021/07
被引用回数:0 パーセンタイル:0.01(Astronomy & Astrophysics)For the first time we search for the in at = 10.52, 10.58, and 10.867 GeV with data samples of 89.5 fb, 711 fb, and 121.4 fb, respectively, accumulated with the Belle detector at the KEKB asymmetric energy electron-positron collider. No significant signal is observed in the mass range between 3.8 and 3.88 GeV/. The upper limit at 90% confidence level on the product of the Born cross section for and branching fraction for is determined to be 4.9 fb at near 10.6 GeV.
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
被引用回数:6 パーセンタイル:45.23(Physics, Particles & Fields)We report the first measurement of the exclusive cross sections , , and in the energy range from 10.63 GeV to 11.02 GeV. The 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 collider.
Moon, T. J.*; 谷田 聖; Belle Collaboration*; 他203名*
Physical Review D, 103(11), p.L111101_1 - L111101_9, 2021/06
被引用回数:18 パーセンタイル:85.82(Astronomy & Astrophysics)We report results from a study of the spin and parity of using a data sample collected by the Belle detector at the KEKB asymmetric-energy collider. The decay angle distributions in the chain are analyzed to determine the spin of this charmed-strange baryon. The angular distributions strongly favor the spin over or , under an assumption that the lowest partial wave dominates in the decay. We also measure the ratio of decay branching fractions / =1.67 , where the last uncertainty is due to possible isospin-symmetry-breaking effects. This value favors the spin-parity with the spin of the light-quark degrees of freedom . This is the first determination of the spin and parity of a charmed-strange baryon.
Lee, J. Y.*; 谷田 聖; Belle Collaboration*; 他201名*
Physical Review D, 103(5), p.052005_1 - 052005_12, 2021/03
被引用回数:6 パーセンタイル:51.62(Astronomy & Astrophysics)We report branching fraction measurements of four decay modes of the baryon, each of which includes an meson and a baryon in the final state, and all of which are measured relative to the decay mode. The results are based on a data sample collected by the Belle detector at the KEKB asymmetric-energy collider. Two decays, and , are observed for the first time, while the measurements of the other decay modes, and , are more precise than those made previously. We obtain / = , / = , / = , and / = . The mass and width of the are also precisely determined to be and , respectively, where the uncertainties are statistical and systematic, respectively.
Li, Y.*; 谷田 聖; Belle Collaboration*; 他205名*
Physical Review D, 102(11), p.112001_1 - 112001_14, 2020/12
被引用回数:5 パーセンタイル:36.79(Astronomy & Astrophysics)We report the results of a first search for a doubly-charged bound state, denoted the , in and inclusive decays and via direct production in collisions at = 10.520, 10.580, and 10.867 GeV. The search uses data accumulated with the Belle detector at the KEKB asymmetric-energy collider. No significant signals are observed in the invariant-mass spectra of all studied modes. The 90% credibility level upper limits on their product branching fractions in and inclusive decays (), and the product values of Born cross section and branching fraction in collisions () at = 10.520, 10.580, and 10.867 GeV under different assumptions of masses varying from 4.13 to 4.17 GeV/, and widths varying from 0 to 5 MeV are obtained.
Oskin, P.*; 谷田 聖; Belle Collaboration*; 他198名*
Physical Review D, 102(9), p.092011_1 - 092011_8, 2020/11
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 collider we search for transitions , and . No significant signals are observed and we set 90% confidence level upper limits on the corresponding visible cross sections: and , respectively.
Yelton, J.*; 谷田 聖; Belle Collaboration*; 他208名*
Physical Review D, 102(7), p.071103_1 - 071103_8, 2020/10
被引用回数:8 パーセンタイル:51.82(Astronomy & Astrophysics)Using 980 fb of data collected with the Belle detector operating at the KEKB asymmetric-energy collider, we report a study of the electromagnetic decays of excited and . A clear signal (8.6 standard deviations) is observed for , and we measure: . We also present evidence (3.8 standard deviations) for the similar decay of the and measure: . The first quoted uncertainties are statistical and the second systematic. We find no hint of the analogous decays of the and baryons and set upper limits at the 90% confidence level of: and Approximate values of the partial widths of the decays are extracted, which can be used to discriminate between models of the underlying quark structure of these excited states.
Li, Y.*; 谷田 聖; Belle Collaboration*; 他175名*
Physical Review D, 100(11), p.112010_1 - 112010_8, 2019/12
被引用回数:1 パーセンタイル:7.79(Astronomy & Astrophysics)Using the data sample of 711 fb of on-resonance data taken by the Belle detector at the KEKB asymmetric-energy electron-positron collider, we present the first measurements of branching fractions of the decays , , and . The signal yields for these decays are extracted from the recoil mass spectrum of the system recoiling against baryons in selected candidates. The branching fraction of is measured to be , where the first uncertainty is statistical and the second is systematic. The 90% credibility level upper limits on and are determined to be and , respectively.
谷田 聖
no journal, ,
最近、実験データはとみに複雑となり、その解析は実験家だけの手には余るようになってきた。その問題点を指摘し、理論と実験が一体となったデータ解析について提案する。
谷田 聖
no journal, ,
I will discuss possibility of hyperon spectroscopy using hyp-TPC at the extended Hadron Experimental Facility of J-PARC.
谷田 聖
no journal, ,
J-PARC is a multipurpose facility devoted to various fields of science including hadron and nuclear physics. Utilizing its high intensity secondary meson beams, several experiments on baryon spectroscopy were performed and planned. I will show the results of recent experiments and introduce new experiments under preparation.
谷田 聖
no journal, ,
Evidence for a narrow resonance at a mass of about 1665 MeV (just above the combined mass of the ground state plus the meson) has been seen in the mass of the Dalitz plot for decay at the Belle experiment. Additional evidence for this resonance is found in the partial-wave analysis (PWA) of data on reactions done independently by several groups, driven by angular distributions of the reaction by the Crystal Ball collaboration. If a narrow resonance exists at this mass, then the conventional quark model cannot explain it, and a possible explanation is that it is a crypto-exotic baryon with a dominant meson-baryon component to its wave function. Therefore we proposed a definitive experiment for , using the newly built hyp-TPC detector to establish the existence of the proposed narrow and determine its spin and parity in two weeks of beamtime at J-PARC (E72), and obtained (scientific) stage-1 approval. We will discuss these evidences for the proposed resonance and introduce the E72 experiment.
谷田 聖
no journal, ,
崩壊のasymmetry parameter について、BESIII実験が数十年ぶりに新しい測定値を報告したが、その値は昔から知られている値よりも20%ほど大きい。もしこれが本当だとすれば、非常に多くの実験・理論が影響を受けることとなるので、昔の測定について調べてみたところ、おそらく間違っているということがわかった。この講演ではどこに間違いがあるのかを報告し、新しい実験を行うことを提案したい。
谷田 聖
no journal, ,
Spin-parity is essential information to understand the structures of charmed baryons, but experimentally there are few measurements yet. In this talk, I will discuss the latest status of spin-parity determination of charmed baryons.
谷田 聖
no journal, ,
I will introduce 3 planned experiments at J-PARC with the newly developed HypTPC detector.
谷田 聖; Belle Collaboration*
no journal, ,
本講演では、Belle実験で測定したバリオンから, , 、そしてへ崩壊する分岐比を報告する。このうち、とへの崩壊は初めて観測されたものである。また、については、質量と幅も同時に決定したので、これについても併せて報告する。