S. Yamashita
A5055795187- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Nuclear Physics and Applications
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Atomic and Molecular Physics
- Superconducting Materials and Applications
- Particle Detector Development and Performance
- Radiation Therapy and Dosimetry
- Dark Matter and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Advanced Chemical Physics Studies
- Medical Imaging Techniques and Applications
- Gyrotron and Vacuum Electronics Research
- Radiation Detection and Scintillator Technologies
- Astronomical and nuclear sciences
- Advanced NMR Techniques and Applications
- Distributed and Parallel Computing Systems
- Pulsars and Gravitational Waves Research
- Muon and positron interactions and applications
Iwate Prefectural University
2024
The University of Tokyo
1997-2012
Kobe University
1996-2005
Université de Montréal
2002
Kyoto University
1969-2000
Meiji University
2000
Argonne National Laboratory
1994
Nara Women's University
1978-1990
Tokyo Institute of Technology
1989
Tokyo University of Agriculture and Technology
1989
Cascade hypernuclei have been studied in the (K−,K+) reaction on a scintillating fiber target. The experimental result is compared with theoretical calculation order to extract information concerning Ξ− nucleus potential.Received 9 April 1998DOI:https://doi.org/10.1103/PhysRevC.58.1306©1998 American Physical Society
The analyzing power AN in inclusive π− and π+ production has been measured with a 200 GeV/c transversely polarized antiproton beam over wide xF range (0.2≤xF≤0.9) at moderate pT (0.2≤pT≤1.5GeV/c). asymmetry increases increasing from zero to large positive values for π−'s, decreases negative π+'s. A threshold the onset of is observed about pT∼0.5GeV/c, below which essentially above (decreases) π−'s ( π+'s) covered range.Received 17 April...
The angular distributions of the reactions Na 23 ( p , α)Ne 20 and K 39 α)A 36 leading to ground first excited states residual nuclei have been measured at 6.9, 7.1 7.3 MeV incident proton energy, respectively, by use a semiconductor detector. For reaction these alpha particles are almost 90° symmetrical they slightly unsymmetrical about 6.9 MeV. all energies protons. It is considered that nuclei, around 7 occur through compound nucleus process in former number protons probably not so many...
We searched for possible signatures of top-quark production in 508 ${e}^{+}{e}^{\ensuremath{-}}$ hadronic annihilation events collected at $\sqrt{s}=52$ GeV by the TOPAZ detector KEK collider TRISTAN. The observed cross section and shape are consistent with standard-model predictions without top quarks. A lower limit (95% confidence level) on mass lightest meson is set 25.8 GeV.
The reaction $\stackrel{-}{p}+\mathrm{Ta}\ensuremath{\rightarrow}{V}^{0}+X$ (${V}^{0}=\ensuremath{\Lambda}, \stackrel{-}{\ensuremath{\Lambda}}, or {K}_{s}^{0}$) at 4 GeV/c has been studied by comparing with the results in $\stackrel{-}{p}p$ interaction. Strong enhancement of $\ensuremath{\Lambda}$ production was observed, while $\stackrel{-}{\ensuremath{\Lambda}}$ is suppressed. $\frac{\stackrel{-}{\ensuremath{\Lambda}}}{\ensuremath{\Lambda}}$ ratio obtained as (2.0...
Sixty-two charm events have been observed in an exposure of the SLAC Hybrid Facility toa backward sacttered laser beam. Based on 22 neutral and 21 charged decays we measured charmed-meson lifetimes to be τD0=(6.8+2.3−1.8)×10−13 sec, τD±=(7.4+2.3−2.0)×10−13 sec their ratio τD±τD0=1.1+0.6−0.3. The inclusive cross section at a photon energy 20 GeV has 56+24−23 nb. Evidence is presented for non-D¯D component production, consistent with (35±20)% Λ+c production some D*± production. We found no...
The angular distributions of alpha-particles and deuterons scattered elastically inelastically by Li 6 7 were measured. 2.18 MeV state , the 0.478 4.63 states appreciably excited. experimental analysed with DWBA theory, deformation parameters above mentioned determined. Experimental results analysis show existence some difference between inelastic scattering while no appreciable was observed in case deuteron scattering. calculation predicts larger quadrupole deformations excited as compared...
The ${\mathrm{\ensuremath{\pi}}}^{0}$ inclusive and semi-inclusive, single-spin asymmetries have been measured using transversely polarized, 200-GeV/c proton antiproton beams colliding with an unpolarized hydrogen target. are consistent zero within the experimental uncertainties for kinematic region -0.15${\mathit{x}}_{\mathit{F}}$+0.15 1${\mathit{p}}_{\mathit{T}}$4.5 GeV/c. Improvements in data analysis showed that our earlier large at ${\mathit{p}}_{\mathit{T}}$\ensuremath{\gtrsim}3 GeV/c...
The analyzing power AN of proton-proton elastic scattering in the Coulomb-nuclear interference region has been measured using 200-GeV/c Fermilab polarized proton beam. A theoretically predicted between hadronic non-spin-flip amplitude and electromagnetic spin-flip is shown for first time to be present at high energies 1.5 × 10−3 5.0 10−2 (GeV/c)2 four-momentum transfer squared, our results are analyzed connection with theoretical calculations. In addition, role possible contributions...
Surprisingly large polarizations in hyperon production by unpolarized protons have been known for a long time. The spin dynamics of the process can be further investigated with polarized beams. Recently, negative asymmetry ${A}_{N}$ was found inclusive ${\ensuremath{\Lambda}}^{0}$ $200\mathrm{GeV}/c$ transversely proton beam. depolarization ${D}_{\mathrm{NN}}$ $p\ensuremath{\uparrow}+p\ensuremath{\rightarrow}{\ensuremath{\Lambda}}^{0}+X$ has measured same beam over wide ${x}_{F}$ range and...
In the reactions Be 9 (α, 2α)He 5 and C 12 2α)Be 8 at 28 MeV, single summed energy spectra of emitted alpha-particles have been measured several pairs angle in order to investigate quasi-free collision between incident alpha-clusters . The spectrum from reaction shows a peak corresponding ground state He angles which particles come nearly zero-momentum momentum spread alpha-cluster coupled with (ground state) is estimated be 0.3 fm -1 angular correlation spectrum, probability finding an this...
The angular distributions have been obtained for alpha-particles from the reactions Be 9 ( p , α) Li 6 (ground state), d 7 (ground, first and second excited states), B 10 8 11 state) elastic inelastic (second scatterings of by . Besides, distribution deuterons reaction ) was measured. energies incident beams were nearly MeV protons, 14 28 alpha-particles. results, except α)Be show forward and/or backward rises may be interpreted direct interactions. integrated cross sections on are larger than those
Angular distributions and total cross sections of the C 12 ( d , α)B 10 O 16 α)N 14 reactions were obtained in deuteron energy range from 15 MeV to 20 MeV. Deuteron energies 15.1, 15.9, 16.7, 17.5, 18.2, 19.0 19.7 reaction, 14.9, 15.4, 15.7, 16.0, 16.5, 16.9, 17.3, 18.1, 18.8 19.6 reaction. Alpha particle groups leaving residual nuclei their low-lying states showed pronounced forward backward peaks simultaneously whole range. Total decreased gradually with increasing energies, but some...
The considerable polarization of hyperons produced at high xF has been known for a long time and interpreted with various theoretical models in terms the constituents' spin. Recently, analyzing power inclusive Λ0 hyperon production also measured using 200GeV/c Fermilab polarized proton beam. covered kinematic range is 0.2≤xF≤1.0 0.1≤pT≤1.5GeV/c. data indicate negative asymmetry large moderate pT. These results can further test current ideas on underlying mechanisms polarization.Received 5...
To investigate the effect of columnar recombination on ionization measurement in air, ratio specific ionizations at two fixed residual ranges for polonium alpha-particles was measured with a shallow chamber under various field strengths and angles between alpha-track. It found that observed varies appreciably varying strength angle. shown variation can be explained by agrees qualitatively Jaffé's theory. The value parameter b formula, which gives best agreement experiments, newly determined...
We have studied inclusive production of ${K}_{S}^{0}$, $\ensuremath{\Lambda}$, and $\overline{\ensuremath{\Lambda}}$ particles in 20-GeV $\ensuremath{\gamma}p$ interactions found features similar to those observed both hadronic leptonic interactions. The cross sections, charged-particle multiplicities, average $\ensuremath{\Lambda}$ polarization are reported. Inclusive distributions $x$ ${p}_{T}$ shown discussed terms quark fragmentation models. Production sections for ${K}^{*}(890)$...