K. Mizutani
A5074445822- Particle physics theoretical and experimental studies
- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Quantum Chromodynamics and Particle Interactions
- Solar and Space Plasma Dynamics
- High-Energy Particle Collisions Research
- Nuclear Physics and Applications
- Nuclear physics research studies
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- Particle Accelerators and Free-Electron Lasers
- Neutrino Physics Research
- Radiation Therapy and Dosimetry
- Medical Imaging Techniques and Applications
- Ionosphere and magnetosphere dynamics
- Calibration and Measurement Techniques
- Superconducting Materials and Applications
- Central Venous Catheters and Hemodialysis
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Extraction and Separation Processes
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Muon and positron interactions and applications
Osaka University
2022-2025
Misasa Onsen Hospital
2024-2025
National and Kapodistrian University of Athens
2023-2024
Thomas Jefferson National Accelerator Facility
2020-2023
Ruhr University Bochum
2023
Duke University
2021
William & Mary
2021
Williams (United States)
2021
Northwestern University
2021
Kyoto University
2012-2018
We have observed cosmic-ray electrons from 10 GeV to 800 by a long duration balloon flight using Polar Patrol Balloon (PPB) in Antarctica. The observation was carried out for 13 days at an average altitude of 35 km January 2004. detector is imaging calorimeter composed scintillating-fiber belts and plastic scintillators inserted between lead plates with 9 radiation lengths. performance the has been confirmed CERN-SPS beam test also investigated Monte-Carlo simulations. New telemetry system...
We measure for the first time differential photoproduction cross section $d\sigma/dt$ of $a_2(1320)$ meson at an average photon beam energy 8.5~GeV, using data with integrated luminosity 104~pb$^{-1}$ collected by GlueX experiment. fully reconstruct $\gamma p \to \eta\pi^0 p$ reaction and perform a partial-wave analysis in mass region amplitudes that incorporate linear polarization beam. This allows us to separate contributions natural- unnatural-parity exchanges. These measurements provide...
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...
The cross sections of the Be7(n,α)He4 reaction for p-wave neutrons were experimentally determined at Ec.m.=0.20–0.81 MeV slightly above big bang nucleosynthesis (BBN) energy window first time on basis detailed balance principle by measuring time-reverse reaction. obtained are much larger than s-wave inferred from recent measurement n_TOF facility in CERN, but significantly smaller theoretical estimation widely used BBN calculations. present results suggest rate is not large enough to solve...
We present a search for axionlike particles, $a$, produced in photon-proton collisions at center-of-mass energy of approximately 4 GeV, focusing on the scenario where $a$-gluon coupling is dominant. The uses $a\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$ and $a\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ decays, data sample corresponding to an integrated luminosity $168\text{ }\text{...
We measured missing mass spectrum of the $^{12}\mathrm{C}(\ensuremath{\gamma},p)$ reaction for first time in coincidence with potential decay products from ${\ensuremath{\eta}}^{\ensuremath{'}}$ bound nuclei. tagged an ($\ensuremath{\eta}+p$) pair associated ${\ensuremath{\eta}}^{\ensuremath{'}}N\ensuremath{\rightarrow}\ensuremath{\eta}N$ process a nucleus. After applying kinematical selections to reduce backgrounds, no signal events were observed bound-state region. An upper limit cross...
The GlueX experiment at Jefferson Lab studies photoproduction of mesons using linearly polarized 8.5GeV photons impinging on a hydrogen target which is contained within detector with near-complete coverage for charged and neutral particles. We present measurements spin-density matrix elements the vector meson ρ(770). statistical precision achieved exceeds that previous experiments in this energy range by orders magnitude. confirm high degree s-channel helicity conservation small squared...
We report the measurement of $\gamma p \rightarrow K^{+}\Lambda$ and K^{+}\Sigma^{0}$ reactions at SPring-8. The differential cross sections photon-beam asymmetries are measured forward $K^{+}$ production angles using linearly polarized tagged-photon beams in range $E_{\gamma}=1.5$--3.0 GeV. With increasing photon energy, for both decrease slowly. Distinct narrow structures section have not been found peaking angular distributions sections, a characteristic feature $t$-channel exchange, is...
Differential cross sections at t=tmin and decay asymmetries for the γp→ϕp reaction have been measured using linearly polarized photons in range 1.5 to 2.9 GeV. These were used determine Pomeron strength factor. The are consistently described by t-channel pseudoscalar exchange model Eγ region above 2.37 In lower energy region, an excess over prediction is observed dependence of differential t=tmin. This observation suggests that additional processes or interference effects between other...
The spin-exotic hybrid meson π1(1600) is predicted to have a large decay rate the ωππ final state. Using 76.6 pb−1 of data collected with GlueX detector, we measure cross sections for reactions γp→ωπ+π−p, γp→ωπ0π0p, and γp→ωπ−π0Δ++ in range Eγ=8–10 GeV. isospin conservation, set first upper limits on photoproduction π10(1600) π1−(1600). We combine these lattice calculations widths find that η′π most sensitive two-body system search π1(1600). locked icon Physics Subject Headings...
Differential cross sections and photon beam asymmetries for the reaction γp→π0p have been measured in energy range of 1.3–2.4GeV π0 polar angle −1<cosθc.m.π0<0.7. The measurement has done by using a large acceptance electromagnetic calorimeter SPring-8 LEPS2/BGOegg experiment. results asymmetry wide are new energies exceeding 1.9GeV. None existing partial wave analysis models describe observed high region. contribution multipole amplitudes with an orbital angular momentum 5 πN system found...
We report on the measurement of spin density matrix elements $\mathrm{\ensuremath{\Lambda}}(1520)$ in photoproduction reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}(1520){K}^{+}$, via its subsequent decay to ${K}^{\ensuremath{-}}p$. The was performed as part GlueX experimental program Hall D at Jefferson Laboratory using a linearly polarized photon beam with...
The differential cross sections and decay angular distributions for coherent $\phi$-meson photoproduction from helium-4 have been measured the first time at forward angles with linearly polarized photons in energy range $E_{\gamma} = \text{1.685-2.385 GeV}$. Thanks to target spin-parity $J^{P} 0^{+}$, unnatural-parity exchanges are prohibited, thus natural-parity can be investigated clearly. asymmetry respect photon polarization is shown very close maximal value. This ensures dominance ($>...
We report a measurement of the π− photoproduction beam asymmetry for reaction →γp→π−Δ++ using data from GlueX experiment in photon energy range 8.2–8.8 GeV. The Σ is measured as function four-momentum transfer t to Δ++ and compared phenomenological models. find that varies t: negative at smaller values positive higher |t|. can be described theoretically by t-channel particle exchange requiring pseudoscalar, vector, tensor intermediaries. In particular, this requires charge exchange, allowing...
We have developed prototype resistive plate chambers (RPCs) for the LEPS2 experiment at SPring-8 in Japan. At LEPS2, RPCs will be used as time-of-flight detectors. The goal is to achieve a time resolution of 50 ps with readout cell large possible. made several types and examined dependence size shape cell. found that efficiency largely depend on position where it excited. confirmed two-ends strip-shaped cells performed better than one-end cells, promising 60 was obtained 2.5 cm (wide) × 108...
For the reaction γp→ωp, differential cross sections, photon beam asymmetries, and spin density matrix elements have been measured in BGOegg experiment at SPring-8 LEPS2 beamline by using a large acceptance electromagnetic calorimeter. A 1.3–2.4 GeV with high linear polarization has enabled precision measurement of asymmetries Σ polarized ρ1−11 over wide angular range, especially above total energy about 2 for first time. The indicates dominance s-channel resonances even higher energies....
We have carried out exclusive measurements for the photoproduction of an $\eta$ meson from a proton target with egg-shaped calorimeter made BGO crystals (BGOegg) and forward charged-particle detectors at SPring-8 LEPS2 beamline. The differential cross sections photon beam asymmetries $\gamma p \to \eta p$ reaction are measured in center-of-mass energy ($W$) range $1.82$-$2.32$ GeV polar angle $-1.0 < \cos{\theta^{\eta}_{\mathrm{c.m.}}} 0.6$. is identified by selecting two $\gamma$'s produced...
We develop a model anisotropy best-fitting to the two-dimensional sky-map of multi-TeV galactic cosmic ray (GCR) intensity observed with Tibet III air shower (AS) array. By incorporating pair excesses in hydrogen deflection plane (HDP) suggested by Gurnett et al., together uni-directional and bi-directional flows for reproducing global feature, this successfully reproduces including "skewed" feature excess from heliotail direction, whose physical origin has long remained unknown. These...
The spin-exotic hybrid meson $\pi_{1}(1600)$ is predicted to have a large decay rate the $\omega\pi\pi$ final state. Using 76.6~pb$^{-1}$ of data collected with GlueX detector, we measure cross sections for reactions $\gamma p \to \omega \pi^+ \pi^- p$, \pi^0 and p\to\omega\pi^-\pi^0\Delta^{++}$ in range $E_\gamma =$ 8-10 GeV. isospin conservation, set first upper limits on photoproduction $\pi^{0}_{1}(1600)$ $\pi^{-}_{1}(1600)$. We combine these lattice calculations widths find that...