相川 脩*; 橋本 直; 谷田 聖; 他73名*
Physics Letters B, 837, p.137637_1 - 137637_8, 2023/02
We measured a set of , , and invariant mass spectra below and above the mass threshold in -induced reactions on deuteron. We deduced the -wave and scattering amplitudes in the isospin 0 channel in the framework of a and coupled channel. We find that a resonance pole corresponding to is located at 1417.7(fitting errors)(systematic errors) + (fitting errors)(systematic errors)] MeV/, closer to the mass threshold than the value determined by the Particle Data Group.
山本 剛史; 藤田 真奈美; 後神 利志*; 原田 健志*; 早川 修平*; 細見 健二; 市川 裕大; 石川 勇二*; 鎌田 健人*; 叶内 萌香*; et al.
EPJ Web of Conferences, 271, p.03001_1 - 03001_5, 2022/11
X-ray spectroscopy of hadronic atoms give us various information on the strong interaction between hadrons and nuclei. At J-PARC, we are aiming for the world-first detection of the X rays from atoms with a doubly strange hyperon, . Recently, two experiments, J-PARC E07 and J-PARC E03, have been performed for the detection of X rays from atoms. Overview and status of these measurements will be presented. We will also discuss future plan of X-ray spectroscopy on -atoms, which can be performed together with high resolution hyper nuclear spectroscopy using newly constructed S-2S spectrometer. Preparation status will be shown in this contribution.
藤田 真奈美; 細見 健二; 石川 勇二*; 叶内 萌香*; 小池 武志*; 小椋 裕*; 田村 裕和; 谷田 聖; 鵜養 美冬*; 山本 剛史
Nuclear Instruments and Methods in Physics Research A, 1042, p.167439_1 - 167439_9, 2022/11
atomic X-ray spectroscopy is a powerful method of studying the N interaction, for which very limited experimental data are currently available. For this reason, we constructed a germanium (Ge) detector array referred to as Hyperball-X and conducted the first-ever atomic X-ray measurements in 2016 and 2017 at J-PARC. We developed a novel method for in-beam energy calibration of Ge detectors. Three rays (202 keV, 307 keV, and 511 keV) from Lu in LSO scintillation counters and Na source were used as reference. The and coincidence detection using the Ge detectors and LSO counters allows for continuous in-beam calibration with this new calibration method, and the calibration uncertainty is reduced to less than 100 eV for energies ranging from 202 to 511 keV.
七村 拓野; 藤田 真奈美; 長谷川 勝一; 市川 真也; 市川 裕大; 今井 憲一*; 成木 恵; 佐藤 進; 佐甲 博之; 田村 裕和; et al.
Progress of Theoretical and Experimental Physics (Internet), 2022(9), p.093D01_1 - 093D01_35, 2022/09
We performed a novel scattering experiment at the J-PARC Hadron Experimental Facility. Approximately 2400 elastic scattering events were identified from tagged particles in the momentum range 0.44 - 0.80 GeV/c. The differential cross sections of the elastic scattering were derived with much better precision than in previous experiments. The obtained differential cross sections were approximately 2 mb/sr or less, which were not as large as those predicted by the fss2 and FSS models based on the quark cluster model in the short-range region. By performing phase-shift analyses for the obtained differential cross sections, we experimentally derived the phase shifts of the and channels for the first time. The phase shift of the 3S1 channel, where a large repulsive core was predicted owing to the Pauli effect between quarks, was evaluated to be . If the sign of is assumed to be negative, the interaction in this channel is moderately repulsive, as the Nijmegen extended-sort-core models predicted.
橋本 直; 谷田 聖; 他68名*
Physical Review Letters, 128(11), p.112503_1 - 112503_6, 2022/03
We have measured the transition X-rays of kaonic He and He atoms using superconducting transition-edge-sensor microcalorimeters with an energy resolution better than 6 eV (FWHM). We determined the energies to be (stat) (syst) eV and (stat) (syst) eV, and widths to be (stat) (syst) eV and (stat) (stat) eV, for kaonic He and He, respectively. These values are nearly 10 times more precise than in previous measurements. Our results exclude the large strong-interaction shifts and widths that are suggested by a coupled-channel approach, and agree with calculations based on optical-potential models.
Kovalenko, E.*; 谷田 聖; Belle Collaboration*; 他181名*
Physical Review D, 104(11), p.112006_1 - 112006_12, 2021/12
We report the first observation of the processes at =10.866 GeV with a and significance respectively. The measured Born cross sections are pb, and pb. We also set the upper limit on the cross section of the process to be ~pb at CL. The results are obtained with the data sample collected with the Belle detector at the KEKB asymmetric-energy collider in the energy range from 10.63 GeV to 11.02 GeV.
van Tonder, R.*; 谷田 聖; Belle Collaboration*; 他202名*
Physical Review D, 104(11), p.112011_1 - 112011_32, 2021/12
We present the measurement of the first to fourth order moments of the four-momentum transfer squared, , of inclusive decays using the full Belle data set of 711 of integrated luminosity at the resonance where . The determination of these moments and their systematic uncertainties open new pathways to determine the absolute value of the CKM matrix element using a reduced set of matrix elements of the heavy quark expansion. In order to identify and reconstruct the system, we reconstruct one of the two -mesons using machine learning techniques in fully hadronic decay modes. The moments are measured with progressively increasing threshold selections on starting with a lower value of 3.0 in steps of 0.5 up to a value of 10.0 . The measured moments are further unfolded, correcting for reconstruction and selection effects as well as QED final state radiation. We report the moments separately for electron and muon final states and observe no lepton flavor universality violating effects.
Cao, L.*; 谷田 聖; Belle Collaboration*; 他199名*
Physical Review Letters, 127(26), p.261801_1 - 261801_8, 2021/12
The first measurements of differential branching fractions of inclusive semileptonic decays are performed using the full Belle data set of 711 fb of integrated luminosity at the resonance and for . 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 decays and other processes, and corrected for resolution and acceptance effects. The measured distributions are compared to predictions from inclusive and hybrid calculations.
Atmacan, H.*; 谷田 聖; Belle Collaboration*; 他219名*
Physical Review D, 104(9), p.L091105_1 - L091105_9, 2021/11
We present a search for the lepton-flavor-violating decays , where , using the full data sample of pairs recorded by the Belle detector at the KEKB asymmetric-energy collider. We use events in which one meson is fully reconstructed in a hadronic decay mode. The lepton is reconstructed indirectly using the momentum of the reconstructed and that of the from the signal decay. We find no evidence for decays and set upper limits on their branching fractions at 90% confidence level of () and ().
Abudinn, F.*; 谷田 聖; Belle II Collaboration*; 他385名*
Physical Review Letters, 127(21), p.211801_1 - 211801_9, 2021/11
We report a measurement of the and lifetimes using and decays reconstructed in data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy collider. The data, collected at center-of-mass energies at or near the resonance, correspond to an integrated luminosity of . The results, and , are the most precise to date and are consistent with previous determinations.
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
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 () are predicted to have a sizeable probability, making them particularly interesting channels to search at various experiments. An updated search via using full data of the Belle experiment, corresponding to an integrated luminosity of 988 fb, 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, and , are set at 90% confidence level.
Adriani, O.*; 谷田 聖; RHICf Collaboration*; 他17名*
Journal of Instrumentation (Internet), 16(10), p.P10027_1 - P10027_16, 2021/10
In the RHIC forward (RHICf) experiment, an operation with collisions was performed at 510 GeV from 24-27 June 2017. The performances, energy and position resolutions, trigger efficiency, stability, and background during the operation, have been studied using data and simulations, which revealed that the requirements for production cross-section and transverse single-spin asymmetry measurements of very forward photons, s, and neutrons were satisfied. In this paper, we describe the details of these studies.
Li, S. X.*; 谷田 聖; Belle Collaboration*; 他193名*
Physical Review D, 104(7), p.072008_1 - 072008_8, 2021/10
Using 980.6 of data collected with the Belle detector operating at the KEKB asymmetric-energy collider, we present a measurement of the branching fraction of the singly Cabibbo-suppressed decay . A clear signal is observed for with a statistical significance of 9.1 standard deviations, and we measure the ratio of branching fractions , from which we infer the branching fraction . The first quoted uncertainty is statistical, the second systematic, and the third from the reference mode .
Acharya, U. A.*; 長谷川 勝一; 今井 憲一*; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他306名*
Physical Review Letters, 127(16), p.162001_1 - 162001_8, 2021/10
Studying spin-momentum correlations in hadronic collisions offers a glimpse into a three-dimensional picture of proton structure. The transverse single-spin asymmetry for midrapidity isolated direct photons in collisions at =200 GeV is measured with the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). Because direct photons in particular are produced from the hard scattering and do not interact via the strong force, this measurement is a clean probe of initial-state spin-momentum correlations inside the proton and is in particular sensitive to gluon interference effects within the proton. This is the first time direct photons have been used as a probe of spin-momentum correlations at RHIC. The uncertainties on the results are a fifty-fold improvement with respect to those of the one prior measurement for the same observable, from the Fermilab E704 experiment. These results constrain gluon spin-momentum correlations in transversely polarized protons.
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
We measure the branching fractions and asymmetries for the singly Cabibbo-suppressed decays , , and , using 980 fb of data from the Belle experiment at the KEKB collider. We obtain where the third uncertainty () is from the uncertainty in the branching fraction of the reference mode . The color-suppressed decay is observed for the first time, with very high significance. The results for the asymmetries are The results for are a significant improvement over previous results. The branching fraction and results for , and the result for , are the first such measurements. No evidence for violation is found in any of these decays.
Li, Y.*; 谷田 聖; Belle Collaboration*; 他190名*
Physical Review D, 104(5), p.052005_1 - 052005_9, 2021/09
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
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.
Li, Y. B.*; 谷田 聖; Belle Collaboration*; 他182名*
Physical Review Letters, 127(12), p.121803_1 - 121803_8, 2021/09
Using data samples of 89.5 and 711 fb recorded at energies of and GeV, respectively, with the Belle detector at the KEKB collider, we report measurements of branching fractions of semileptonic decays ( or ) and the -asymmetry parameter of decay. The branching fractions are measured to be )=()% and )=()%, and the decay parameter is measured to be with much improved precision compared to the current world average. The corresponding ratio / is 1.03 0.05 0.07, which is consistent with the expectation of lepton flavor universality. The first measured asymmetry parameter 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 branching fraction.
Nisar, N. K.*; 谷田 聖; Belle Collaboration*; 他197名*
Physical Review D, 104(3), p.L031101_1 - L031101_8, 2021/08
We report the results of the first search for the decay using of data collected at the resonance with the Belle detector at the KEKB asymmetric-energy collider. We observe no significant signal and set a 90% confidence-level upper limit of on the branching fraction of this decay.
Cao, L.*; 谷田 聖; Belle Collaboration*; 他236名*
Physical Review D, 104(1), p.012008_1 - 012008_32, 2021/07
We present measurements of partial branching fractions of inclusive semileptonic decays using the full Belle data set of 711 fb of integrated luminosity at the resonance and for . Inclusive semileptonic decays are CKM suppressed and measurements are complicated by the large background from CKM-favored transitions, which have a similar signature. Using machine learning techniques, we reduce this and other backgrounds effectively, whilst retaining access to a large fraction of the phase space and high signal efficiency. We measure partial branching fractions in three phase-space regions covering about to of the accessible phase space. The most inclusive measurement corresponds to the phase space with lepton energies of GeV, and we obtain from a two-dimensional fit of the hadronic mass spectrum and the four-momentum-transfer squared distribution, with the uncertainties denoting the statistical and systematic error. We find from an average of four calculations for the partial decay rate with the third uncertainty denoting the average theory error. This value is higher but compatible with the determination from exclusive semileptonic decays within 1.3 standard deviations.