T. Ishikawa
A5036805192- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- Nuclear Physics and Applications
- Particle Detector Development and Performance
- Advanced NMR Techniques and Applications
- Dark Matter and Cosmic Phenomena
- Superconducting Materials and Applications
- Quantum, superfluid, helium dynamics
- Neutrino Physics Research
- Atomic and Molecular Physics
- Particle Accelerators and Free-Electron Lasers
- Medical Imaging Techniques and Applications
- Advanced X-ray Imaging Techniques
- Photonic and Optical Devices
- Advanced Chemical Physics Studies
- Semiconductor Lasers and Optical Devices
- Magnetic properties of thin films
- Crystallography and Radiation Phenomena
- Magnetic confinement fusion research
- Phase-change materials and chalcogenides
- Muon and positron interactions and applications
Osaka University
2013-2025
Tohoku University
2013-2022
Tokyo Institute of Technology
2022
The University of Tokyo
1984-2020
High Energy Accelerator Research Organization
1991-2020
Kyoto University
1999-2020
University of Science and Technology of China
2020
Tohoku Gakuin University
2020
Advanced Science Research Center
2020
Japan Atomic Energy Agency
2020
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.
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,...
The photo-production of ϕ mesons from Li, C, Al, and Cu at forward angles has been measured Eγ=1.5–2.4GeV. number events for incoherent is found to have a target mass dependence A0.72±0.07 in the kinematical region |t|⩽0.6GeV2/c2. total cross section ϕ–nucleon interaction, σϕN, estimated as 35−11+17mb using A-dependence yield Glauber-type multiple scattering theory. This value much larger than σϕN free space, suggesting that properties might change nuclear medium.
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...
Differential cross sections for γp→K+Λ(1405) and γp→K+Σ0(1385) reactions have been measured in the photon energy range from 1.5 to 2.4 GeV angular of 0.8<cos(Θ)<1.0 K+ scattering angle center-of-mass system. This data is first measurement Λ(1405) photoproduction section. The line shapes Σ+π− Σ−π+ decay modes were different with each other, indicating a strong interference isospin 0 1 terms Σπ amplitudes. ratios production Σ0(1385) two ranges: near threshold (1.5<Eγ<2.0 GeV) far it...
A search for $K^-pp$ bound state (the lightest kaonic nucleus) has been performed using the $\gamma d \rightarrow K^+ \pi^- \rm{X}$ reaction at E$_\gamma$=1.5-2.4 GeV LEPS/SPring-8. The differential cross section of $K^+ \pi^-$ photo-production off deuterium measured first time in this energy region, and a bump structure was searched inclusive missing mass spectrum. statistically significant not observed region from 2.22 to 2.36 GeV/$c^2$, upper limits production were determined be 0.1$-$0.7...
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.
Cross sections and analyzing powers for proton elastic scattering from $^{116,118,120,122,124}\mathrm{Sn}$ at 295 MeV have been measured a momentum transfer of up to about 3.5 fm${}^{\ensuremath{-}1}$ deduce systematic changes the neutron density distribution. We tuned relativistic Love-Franey interaction explain nucleus whose distribution is well known. Then, we applied this distributions tin isotopes. The result our analysis shows clear behavior gradual increase in skin thickness isotopes...
\ensuremath{\eta} mesons emitted from the photoproduction off protons were measured for $0.70\ensuremath{\leqslant}{E}_{\ensuremath{\gamma}}\ensuremath{\leqslant}1.15$ GeV. The $\ensuremath{\gamma}p\ensuremath{\rightarrow}\ensuremath{\eta}p$ reaction process was separated $\ensuremath{\pi}\ensuremath{\eta}p$ final state by momentum difference of ${E}_{\ensuremath{\gamma}}\ensuremath{\geqslant}930$ MeV. angular distributions obtained and excitation function are essentially in good agreement...
In positron emission tomography (PET), time-of-flight (TOF) information localizes source positions along lines of response. Cherenkov-radiator-integrated microchannel-plate photomultiplier tubes have achieved 30 ps TOF resolution, demonstrating cross-sectional imaging without reconstruction. Such ultrafast detectors would free PET from conventional ring geometries. Therefore, this study aimed at investigating characteristics a dual-panel with using Geant4 simulation. Two detector panels...
We present prospects for the \({\mit \Theta }^+\) pentaquark baryon search using newly constructed LEPS2 facility at SPring-8. The detector system features significant improvements in acceptance multi-particle final states compared to previous experiments. Our employs two complementary strategies: direct production \(\gamma n \to K^-{\mit reaction a liquid deuterium target with photon beam up 2.4 GeV, and \(\bar {K}^{*0}\)-associated hydrogen 2.9 GeV. extended covers both forward large-angle...
Background-free inelastic scattering spectra have been obtained for five Sm isotopes with $386\text{\ensuremath{-}}\text{MeV}$ $\ensuremath{\alpha}$ particles at forward angles (including $0\ifmmode^\circ\else\textdegree\fi{}$) to investigate the effect of deformation on compressional-mode giant resonances. The strength distributions $L\ensuremath{\leqslant}3$ isoscalar resonances extracted via a multipole decomposition analysis using angular calculated in framework density-dependent...
Differential cross sections and photon-beam asymmetries have been measured for the gamma n --> K+ Sigma- p K+Sigma0 reactions separately using liquid deuterium hydrogen targets with incident linearly polarized photon beams of E = 1.5-2.4 GeV at 0.6 < cos ThetacmK< 1. The section ratio sigma Sigma-/sigma Sigma0, expected to be 2 on basis isospin 1/2 exchange, is found close For reaction, large positive are observed, indicating dominance K* exchange. difference between Sigma0 cannot explained...
Differential and total cross sections of the D(γ,η)pn reaction have been measured for photon energies between 600 1150 MeV. The data provide information γn →ηn above Eγ ≥ 800 section shows a narrow resonance structure peaked at = 1020 angular distribution coefficients together with are compared calculation isobar model by using impulse approximation. Although spin parity cannot be determined unambiguously, negative assignment gives better fit to data.
Differential cross sections and photon-beam asymmetries for the gamma p -> K+ Lambda(1520) reaction have been measured with linearly polarized photon beams at energies from threshold to 2.4 GeV 0.6<cos(theta)<1. A new bump structure was found W=2.11 in sections. The is not well reproduced by theoretical calculations introducing a nucleon resonance J<=3/2. This result suggests that might be produced possibly J>=5/2 or process, example an interference effect phi photoproduction having similar
ABSTRACT In the late stages of nuclear burning for massive stars ( M > 8 ⊙ ), production neutrino–antineutrino pairs through various processes becomes dominant stellar cooling mechanism. As star evolves, energy these neutrinos increases and in days preceding supernova a significant fraction emitted electron anti-neutrinos exceeds threshold inverse beta decay on free hydrogen. This is golden channel liquid scintillator detectors because coincidence signature allows reductions background...
The total cross sections were measured for coherent double neutral-pion photoproduction on the deuteron at incident energies below 0.9 GeV first time. No clear resonance-like behavior is observed in excitation function Wγd=2.38–2.61 GeV, where d⁎(2380) dibaryon resonance COSY expected to appear. consistent with existing theoretical calculation this reaction. upper limit of section found be 0.034μb Wγd=2.37 (90% confidence level) γd→π0π0d
KamLAND-Zen reports on a preliminary search for neutrinoless double-beta decay with 136Xe based 114.8 live-days after the purification of xenon loaded liquid scintillator. In this data, problematic 110mAg background peak identified in previous searches is reduced by more than factor 10. By combining pre- and post-purification we obtain lower limit 0νββ half-life T1/20ν>2.6×1025 yr at 90% C.L. The sensitivity will be enhanced additional low data purification. Prospects further improvements...