S. Ishimoto
A5034666360- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Atomic and Subatomic Physics Research
- Superconducting Materials and Applications
- Nuclear Physics and Applications
- Advanced NMR Techniques and Applications
- Quantum, superfluid, helium dynamics
- Muon and positron interactions and applications
- Particle accelerators and beam dynamics
- Particle Detector Development and Performance
- Particle Accelerators and Free-Electron Lasers
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Physics of Superconductivity and Magnetism
- Superconducting and THz Device Technology
- Dark Matter and Cosmic Phenomena
- Astronomical and nuclear sciences
- High-pressure geophysics and materials
- Spacecraft and Cryogenic Technologies
- Geophysics and Gravity Measurements
- Cold Atom Physics and Bose-Einstein Condensates
- Radiopharmaceutical Chemistry and Applications
- Atomic and Molecular Physics
High Energy Accelerator Research Organization
2015-2024
Yamagata University
2014-2024
Yamagata University Hospital
2020-2024
RIKEN Nishina Center
2011-2023
A. Alikhanyan National Laboratory
2023
Ulsan National Institute of Science and Technology
2023
University of Aveiro
2018-2023
Institute of Particle and Nuclear Studies
2005-2022
Tokyo Institute of Technology
2022
Charles University
2020
We present the final results of spin asymmetries A1 and structure functions g1 proton deuteron in kinematic range 0.0008<x<0.7 0.2<Q2<100GeV2. For determination A1, addition to usual method which employs inclusive scattering events includes a large radiative background at low x, we use new minimizes by selecting with least one hadron as well muon state. find that this gives smaller errors for x<0.02, so it is combined provide optimal set results.Received 18 May...
The energy spacing of the spin-doublet states in ${}_{\mathrm{\ensuremath{\Lambda}}}^{4}$He hypernucleus indicate a large spin dependent charge symmetry breaking $\mathrm{\ensuremath{\Lambda}}\phantom{\rule{0}{0ex}}N$ interaction.
We present a new measurement of the spin-dependent structure function g1d deuteron in deep inelastic scattering 190 GeV polarised muons on deuterons, kinematic range 0.003 < x 0.7 and 1 GeV2 Q2 60 GeV2. This is found to be negative at small x. The first moment Γ1d=∫01g1ddx evaluated Q02 = 10 0.034 ± 0.009 (stat.) 0.006 (syst.). value below Ellis-Jaffe sum rule prediction by three standard deviations. Using our earlier determination Γ1p, we obtain Γ1p − Γ1n 0.199 0.038 which agrees with Bjorken rule.
We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering polarised muons on protons deuterons in the range 0.003<x<0.7 Q2>1 GeV2. Compared to our previous publication this subject, with new data statistical errors have been reduced by nearly factor two. From these inclusive we determine quark distributions valence quarks non-strange sea at Q2=10 The u distribution, Δuv(x), is positive polarisation increases x. d...
We have measured the proton energy distribution from 4He(stopped K−,p) reaction by means of time-of-flight. A mono-energetic peak was observed, which is interpreted as formation a new kind neutral tribaryon S0(3115) with isospin T=1 and strangeness S=−1. The mass width state were deduced to be 3117.0−4.4+1.5MeV/c2 <21MeV/c2, respectively. mainly decays into ΣNN.
The COMPASS collaboration at CERN has measured diffractive dissociation of 190 GeV/$c$ pions into the $\pi^-\pi^-\pi^+$ final state using a stationary hydrogen target. A partial-wave analysis (PWA) was performed in bins $3\pi$ mass and four-momentum transfer isobar model so far largest PWA consisting 88 waves. narrow $J^{PC} = 1^{++}$ signal is observed $f_0(980)\,\pi$ channel. We present resonance-model study subset spin-density matrix selecting states with 2^{++}$ $4^{++}$ decaying...
We observed a distinct peak in the Λp invariant mass spectrum of He3(K−,Λp)n, well below mK+2mp, i.e., threshold K− to be bound two protons. By selecting relatively large momentum-transfer region q=350∼650 MeV/c, one can kinematically separate from quasi-free process, K‾N→K‾N followed by non-resonant absorption spectator-nucleons K‾NN→ΛN. found that simplest fit gives us Breit–Wigner pole position at BKpp=47±3(stat.)−6+3(sys.) MeV having width ΓKpp=115±7(stat.)−20+10(sys.) MeV, and S-wave...
We present a next-to-leading order QCD analysis of the presently available data on spin structure function g1 including final from Spin Muon Collaboration. results for first moments proton, deuteron, and neutron functions, determine singlet nonsinglet parton distributions in two factorization schemes. also test Bjorken sum rule find agreement with theoretical prediction at level 10%.Received 18 May 1998DOI:https://doi.org/10.1103/PhysRevD.58.112002©1998 American Physical Society
We present a measurement of the longitudinal spin cross section asymmetry for deep-inelastic muon-nucleon interactions with two high transverse momentum hadrons in final state. Two methods event classification are used to increase contribution photon-gluon fusion process above 30%. The most effective one, based on neural network approach, provides asymmetries Al→NlhhXp=0.030±0.057(stat)±0.010(syst) and Al→NlhhXd=0.070±0.076(stat)±0.010(syst). From these values we derive an averaged gluon...
We present a new measurement of the spin-dependent structure function g1d deuteron from deep inelastic scattering 190 GeV polarized muons on deuterons. The results are combined with our previous measurements g1d. A perturbative QCD evolution in next-to-leading order is used to compute g1d(x) at constant Q2. At Q2 = 10 GeV2, we obtain first moment Γ1d=∫1dg1ddx=0.041±0.008, flavour-singlet axial charge nucleon a0 0.30 ± 0.08, and an strange quark as −0.09 0.03. Using earlier determination Γ1p,...
We measured the spin asymmetry in scattering of 100 GeV longitudinally-polarized muons on transversely polarized protons. The was found to be compatible with zero kinematic range 0.006 < x 0.6, 1 Q2 30GeV2. From this result we derive upper limits for virtual photon-proton A2, and structure function g2. For 0.15, A2 is significantly smaller than its positivity limit √R.
We have measured the Balmer-series x-rays of kaonic $^4$He atoms using novel large-area silicon drift x-ray detectors in order to study low-energy $\bar{K}$-nucleus strong interaction. The energy $3d \to 2p$ transition was determined be 6467 $\pm$ 3 (stat) 2 (syst) eV. resulting strong-interaction energy-level shift is agreement with theoretical calculations, thus eliminating a long-standing discrepancy between theory and experiment.
The semi-inclusive difference asymmetry A^{h^{+}-h^{-}} for hadrons of opposite charge has been measured by the COMPASS experiment at CERN. data were collected in years 2002-2004 using a 160 GeV polarised muon beam scattered off large ^6LiD target and cover range 0.006 < x 0.7 1 Q^2 100 (GeV/c)^2. In leading order QCD (LO) A_d^{h^{+}-h^{-}} measures valence quark polarisation provides an evaluation first moment Delta u_v + d_v which is found to be equal 0.40 +- 0.07 (stat.) 0.05 (syst.)...
The COMPASS experiment at the CERN SPS has studied diffractive dissociation of negative pions into π−π−π+ final state using a 190 GeV/c pion beam hitting lead target. A partial wave analysis been performed on sample 420 000 events taken values squared 4-momentum transfer t′ between 0.1 and 1 GeV2/c2. well-known resonances a1(1260), a2(1320), π2(1670) are clearly observed. In addition, data show significant natural-parity exchange production resonance with spin-exotic quantum numbers JPC=1−+...
The international Muon Ionization Cooling Experiment (MICE), which is under construction at the Rutherford Appleton Laboratory (RAL), will demonstrate principle of ionization cooling as a technique for reduction phase-space volume occupied by muon beam. channels are required Neutrino Factory and Collider. MICE evaluate in detail performance single lattice cell Feasibility Study 2 channel. Beam has been constructed ISIS synchrotron RAL, Step I, it characterized using beam-instrumentation...
The first conclusive evidence of a dipole resonance in ^{11}Li having isoscalar character observed from inelastic scattering with novel solid deuteron target is reported. experiment was performed at the newly commissioned IRIS facility TRIUMF. results show peak an excitation energy 1.03±0.03 MeV width 0.51±0.11 (FWHM). angular distribution consistent distorted-wave Born approximation framework. together shell model calculations signature that monopole tensor interaction important ^{11}Li. ab...
The differential cross sections of the Σ^{-}p→Λn reaction were measured accurately for Σ^{-} momentum (p_{Σ}) ranging from 470 to 650 MeV/c at J-PARC Hadron Experimental Facility. Precise angular information about was obtained first time by detecting approximately 100 events each step Δcosθ=0.1. show a slightly forward-peaking structure in regions. integrated -0.7≤cosθ≤1.0 as 22.5±0.68 [statistical error(stat.)] ±0.65 [systematic error(syst.)] mb and 15.8±0.83(stat)±0.52(syst)...
We present the results of spin asymmetries ${A}_{1}$ proton and deuteron in kinematic region extending down to $x=6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ ${Q}^{2}=0.01{\mathrm{GeV}}^{2}.$ The data were taken with a dedicated low x trigger, which required hadron detection addition scattered muon, so as reduce background at x. complement our previous measurements two sets are consistent overlap region. No significant effects found newly explored