Y. Miyachi
A5006996902- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- Nuclear Physics and Applications
- Particle Detector Development and Performance
- Neutrino Physics Research
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Dark Matter and Cosmic Phenomena
- Radiation Detection and Scintillator Technologies
- Muon and positron interactions and applications
- Nuclear physics research studies
- Quantum, superfluid, helium dynamics
- Astrophysics and Cosmic Phenomena
- Advanced X-ray Imaging Techniques
- Solid-state spectroscopy and crystallography
- Atmospheric Ozone and Climate
- Crystallography and Radiation Phenomena
- Graphite, nuclear technology, radiation studies
- Radioactivity and Radon Measurements
- Particle accelerators and beam dynamics
- Matrix Theory and Algorithms
- Cellular Automata and Applications
Yamagata University Hospital
2010-2024
Yamagata University
2012-2024
University of Aveiro
2017-2023
A. Alikhanyan National Laboratory
2023
Mississippi State University
2023
Ruhr University Bochum
2020-2023
University of Miyazaki
2020-2023
University of Trieste
2023
University of Illinois System
2020-2023
Charles University
2020-2023
The gamman-->K(+)K(-)n reaction on 12C has been studied by measuring both K+ and K- at forward angles. A sharp baryon resonance peak was observed 1.54+/-0.01 GeV/c(2) with a width smaller than 25 MeV/c(2) Gaussian significance of 4.6sigma. strangeness quantum number (S) the is +1. It can be interpreted as molecular meson-baryon or alternatively an exotic five-quark state (uuddsmacr;) that decays into neutron. consistent lowest member antidecuplet baryons predicted chiral soliton model.
Azimuthal single-spin asymmetries of lepto-produced pions and charged kaons were measured on a transversely polarized hydrogen target. Evidence for naive-T-odd, transverse-momentum-dependent parton distribution function is deduced from non-vanishing Sivers effects pi+, pi0, K+, K-, as well in the difference pi+ pi- cross sections.
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...
Single-spin asymmetries for pions and charged kaons are measured in semi-inclusive deep-inelastic scattering of positrons electrons off a transversely nuclear-polarized hydrogen target. The dependence the cross section on azimuthal angles target polarization (phi_S)and produced hadron (phi) is found to have substantial sin(phi+phi_S) modulation production pi+, pi- K+. This Fourier component can be interpreted terms non-zero transversity distribution functions favored disfavored Collins...
Differential cross sections and photon beam asymmetries for the gamma p rightarrow K+ Lambda Sigma0 reactions have been measured in energy range from 1.5 GeV to 2.4 angular Theta_{cm} = 0 60 of scattering angle center mass system at SPring-8/LEPS facility. The both found be positive increase with energy. differential agree data by CLAS collaboration cosTheta_{cm}<0.9 within experimental uncertainties, but discrepancy SAPHIR K+Lambda reaction is large cosTheta_{cm}>0.9. In reaction,...
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...
The γd→K+K−pn reaction has been studied to search for the evidence of Θ+ by detecting K+K− pairs at forward angles. Fermi-motion-corrected nK+ invariant mass distribution shows a narrow peak 1.524±0.002+0.003 GeV/c2. statistical significance calculated from shape analysis is 5.1 σ, and differential cross section γn→K−Θ+ estimated be 12±2 nb/sr in photon energy range 2.0 2.4 GeV LEPS angular assuming isotropic production γn center-of-mass system. obtained results support existence Θ+.9...
The SciBooNE Collaboration reports a measurement of inclusive charged current interactions muon neutrinos on carbon with an average energy 0.8 GeV using the Fermilab Booster Neutrino Beam. We compare our two neutrino interaction simulations: NEUT and NUANCE. rates (product flux cross section) are extracted by fitting kinematics, precision 6-15% for dependent 3% integrated analyses. also extract CC sections from observed rates, 10-30% 8% This is first section around 1 GeV. These results can...
The azimuthal cos{\phi} and cos2{\phi} modulations of the distribution hadrons produced in unpolarized semi-inclusive deep-inelastic scattering electrons positrons off hydrogen deuterium targets have been measured HERMES experiment. For first time these were determined a four-dimensional kinematic space for positively negatively charged pions kaons separately, as well unidentified hadrons. These dependences are sensitive to transverse motion polarization quarks within nucleon via, e.g.,...
Beam-helicity and beam-charge asymmetries in the hard exclusive leptoproduction of real photons from an unpolarised hydrogen target by a 27.6 GeV lepton beam are extracted HERMES data set 2006-2007 using missing-mass event selection technique. The asymmetry amplitudes this more precise than those earlier 1996-2005 previously analysed same manner HERMES. results two sets compatible with each other. Results these combined constitute most amplitude measurements made kinematic region
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
Beam polarization asymmetries for the p(gamma-->,K+)Lambda and p(gamma-->,K+)Sigma(0) reactions are measured first time E(gamma)=1.5-2.4 GeV 0.6<cos((theta(c.m.)(K+))<1.0 by using linearly polarized photons at Laser-Electron-Photon facility SPring-8 (LEPS). The observed positive gradually increase with rising photon energy. data not consistent theoretical predictions based on tree-level effective-Lagrangian approaches. Including new results in development of models is, therefore, crucial...
Photoproduction of a phi meson on protons was studied by means linearly polarized photons at forward angles in the low-energy region from threshold to Egamma = 2.37 GeV. The differential cross sections t -|t|min do not increase smoothly as increases but show local maximum around 2.0 angular distributions demonstrate that mesons are photoproduced predominantly helicity-conserving processes, and is likely due unnatural-parity processes.
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...
The SciBooNE Collaboration has performed a search for charged current coherent pion production from muon neutrinos scattering on carbon, ${\ensuremath{\nu}}_{\ensuremath{\mu}}^{12}\mathrm{C}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}^{12}\mathrm{C}{\ensuremath{\pi}}^{+}$, with two distinct data samples. No evidence is observed. We set 90% confidence level upper limits the cross section ratio of to total at $0.67\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$ mean...
The MiniBooNE and SciBooNE collaborations report the results of a joint search for short baseline disappearance ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}$ at Fermilab's Booster Neutrino Beamline. Cherenkov detector tracking observe antineutrinos from same beam, therefore combined analysis their data sets serves to partially constrain some flux cross section uncertainties. Uncertainties in ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ background were constrained by neutrino measurements...
A bstract The beam-helicity asymmetry in exclusive electroproduction of real photons by the longitudinally polarized Hera positron beam scattering off an unpolarized hydrogen target is measured at Hermes. arises from deeply virtual Compton and its interference with Bethe-Heitler process. Azimuthal amplitudes are extracted a data sample consisting ep → epγ events detection all particles final state including recoiling proton. installation recoil detector, while reducing acceptance experiment,...
Double-spin asymmetries in exclusive electroproduction of real photons from a transversely polarized hydrogen target are measured with respect to the product polarization beam helicity and charge, alone. The arise deeply virtual Compton scattering process its interference Bethe--Heitler process. They related part same combination form factors as that determining previously published transverse single-spin through imaginary part. results for double-spin found be compatible zero within...
A bstract comprehensive set of azimuthal single-spin and double-spin asymmetries in semi-inclusive leptoproduction pions, charged kaons, protons, antiprotons from transversely polarized protons is presented. These include the previously published HERMES results on Collins Sivers asymmetries, analysis which has been extended to also an extraction a three-dimensional kinematic binning enlarged phase space. They are complemented by corresponding for remaining four allowed one-photon-exchange...
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