A. Yamamoto
A5079952648- Particle physics theoretical and experimental studies
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- High-Energy Particle Collisions Research
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Quantum Chromodynamics and Particle Interactions
- Dark Matter and Cosmic Phenomena
- Muon and positron interactions and applications
- Astrophysics and Cosmic Phenomena
- Neutrino Physics Research
- Spacecraft and Cryogenic Technologies
- Pulsars and Gravitational Waves Research
- Computational Physics and Python Applications
- Atomic and Subatomic Physics Research
- Nuclear physics research studies
- Physics of Superconductivity and Magnetism
- Cosmology and Gravitation Theories
- Solar and Space Plasma Dynamics
- Geophysics and Sensor Technology
- Atomic and Molecular Physics
- Quantum, superfluid, helium dynamics
- Radiation Therapy and Dosimetry
- Geophysics and Gravity Measurements
- Superconductivity in MgB2 and Alloys
High Energy Accelerator Research Organization
2015-2024
Shinshu University Hospital
2024
Kyoto University
2022-2023
The University of Tokyo
2008-2023
RIKEN
2011-2023
Pioneer (Japan)
2023
Weatherford College
2022
MRC Centre for Regenerative Medicine
2022
Kyoto Pharmaceutical University
2022
Uppsala University
2017-2020
We present the final report from a series of precision measurements muon anomalous magnetic moment, ${a}_{\ensuremath{\mu}}=(g\ensuremath{-}2)/2$. The details experimental method, apparatus, data taking, and analysis are summarized. Data obtained at Brookhaven National Laboratory, using nearly equal samples positive negative muons, were used to deduce ${a}_{\ensuremath{\mu}}(\mathrm{\text{Expt}})=11659208.0(5.4)(3.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$, where...
The anomalous magnetic moment of the negative muon has been measured to a precision 0.7 ppm (ppm) at Brookhaven Alternating Gradient Synchrotron. This result is based on data collected in 2001, and over an order magnitude more precise than previous measurement for muon. a(mu(-))=11 659 214(8)(3) x 10(-10) (0.7 ppm), where first uncertainty statistical second systematic, consistent with measurements anomaly positive average a(mu)(exp)=11 208(6) (0.5 ppm).
The final results of the search for lepton flavour violating decay $$\mathrm {\mu }^+ \rightarrow \mathrm {e}^+ {\gamma }$$ based on full dataset collected by MEG experiment at Paul Scherrer Institut in period 2009–2013 and totalling $$7.5\times 10^{14}$$ stopped muons target are presented. No significant excess events is observed with respect to expected background a new upper limit branching ratio this $$ \mathcal{B} (\mu ^+ \mathrm{e}^+ \gamma ) < 4.2 \times 10^{-13}$$ (90 % confidence...
Three independent searches for an electric dipole moment (EDM) of the positive and negative muons have been performed, using spin precession data from muon g-2 storage ring at Brookhaven National Laboratory. Details on experimental apparatus three analyses are presented. Since individual results muon, as well combined result, d=-0.1(0.9)E-19 e-cm, all consistent with zero, we set a new EDM limit, |d| < 1.9E-19 e-cm (95% C.L.). This represents factor 5 improvement over previous best limit EDM.
A higher precision measurement of the anomalous g value, a(mu)=(g-2)/2, for positive muon has been made at Brookhaven Alternating Gradient Synchrotron, based on data collected in year 2000. The result a(mu(+))=11 659 204(7)(5)x10(-10) (0.7 ppm) is good agreement with previous measurements and an error about one-half that combined data. present world average experimental value a(mu)(expt)=11 203(8)x10(-10) ppm).
We report cosmic-ray proton and helium spectra in energy ranges of 1-120 GeV nucleon-1 1-54 nucleon-1, respectively, measured by a flight the Balloon-borne Experiment with Superconducting Spectrometer (BESS) 1998. The magnetic rigidity cosmic ray was reliably determined highly precise measurement circular track uniform solenoidal field 1 T. Those were within overall uncertainties ±5% for protons ±10% nuclei including statistical systematic errors.
Primary and atmospheric cosmic-ray spectra were precisely measured with the BESS-TeV spectrometer. The spectrometer was upgraded from BESS-98 to achieve seven times higher resolution in momentum measurement. We report absolute fluxes of primary protons helium nuclei energy ranges, 1–540 GeV 1–250 GeV/n, respectively, flux muons range 0.6–400 GeV/c.
The energy spectrum of cosmic-ray antiprotons (¯p's) from 0.17 to 3.5 GeV has been measured using 7886 ¯p's detected by BESS-Polar II during a long-duration flight over Antarctica near solar minimum in December 2007 and January 2008. This shows good consistency with secondary ¯p calculations. Cosmologically primary have investigated comparing calculated spectra. data show no evidence the evaporation primordial black holes.Received 28 July...
Various superconducting detector solenoids for particle physics have been developed in the world. The key technology is aluminum-stabilized conductor almost all magnets experiments. With progress of conductor, coil fabrication has progressed as well, such inner winding technique, indirect cooling, transparent vacuum vessel, quench protection scheme using pure aluminum strips and so on. design study future big projects Japan Europe, that is, ILC, FCC CLIC, based on technologies established...
The energy spectra of cosmic-ray low-energy antiprotons ( $\overline{p}$'s) and protons $p$'s) have been measured by BESS in 1999 2000, during a period covering reversal at the solar magnetic field. Based on these measurements, sudden increase $\overline{p}/p$ flux ratio following field was observed, it generally agrees with drift model modulation.
A search for solar axions has been performed using an axion helioscope which is equipped with a 2.3m-long 4T superconducting magnet, gas container to hold dispersion-matching gas, PIN-photodiode X-ray detectors, and telescope mount mechanism track the sun. mass region around m_a = 1eV was newly explored. From absence of any evidence, analysis sets limit on axion-photon coupling constant be g < 5.6-13.4x10^{-10} GeV^{-1} 0.84
The ground state hyperfine splitting of positronium ΔHFS is sensitive to high order corrections quantum electrodynamics (QED) in bound state. theoretical prediction and the averaged experimental value for have a discrepancy 15 ppm, which equivalent 3.9 standard deviations (s.d.). A new precision measurement reduces systematic uncertainty from thermalization effect was performed, non-thermalization measured be as large 10±2ppm timing window we used. When this taken into account, our result...
New data on quasifree polarized neutron-proton scattering in the region of recently observed ${d}^{*}$ resonance structure are obtained by exclusive and kinematically complete high-statistics measurements with WASA at COSY. This paper details determination beam polarization, checks character process, all ${A}_{y}$ angular distributions new partial-wave analysis, which includes producing a pole ${}^{3}{D}_{3}\ensuremath{-}{}^{3}{G}_{3}$ coupled partial waves...
Exclusive measurements of the quasi-free $np \to np\pi^0\pi^0$ reaction have been performed by means $dp$ collisions at $T_d$ = 2.27 GeV using WASA detector setup COSY. Total and differential cross sections obtained covering energy region $\sqrt s$ (2.35 - 2.46) GeV, which includes ABC effect its associated $d^*(2380)$ resonance. Adding $d^*$ resonance amplitude to that for conventional processes leads a reasonable description data. The observed in total section is agreement with predictions...
The BESS-Polar Collaboration measured the energy spectra of cosmic-ray protons and helium during two long-duration balloon flights over Antarctica in December 2004 2007, at substantially different levels solar modulation. Proton probe origin propagation history cosmic rays galaxy, are essential to calculations expected antiprotons, positrons, electrons from interactions primary nuclei with interstellar gas, atmospheric muons neutrinos. We report absolute top atmosphere for kinetic range...
We present here the Large-scale Cryogenic Gravitational wave Telescope (LCGT) project which is aimed to improve sensitivity of existing gravitational projects by ten times. LCGT constructing km-scale detector in Japan succeeding TAMA project, adopts cryogenic mirrors with a higher power laser. are planing build it an underground site Kamioka mine. If its target attained, we will be able catch few events per month.
The cosmic-ray hydrogen and helium spectra have been measured by the Balloon Borne Experiment with a Superconducting Solenoid Spectrometer (BESS), which has flown from Lynn Lake, Manitoba, Canada, annually since 1993. BESS experiment provides excellent rigidity measurement precise particle identification large geometric acceptance. We present here nuclei energy 0.2 to 10 GeV nucleon-1 their isotopic composition about 1 for first flight. This simultaneous measurements of secondaries,...
We performed a search for cosmic-ray antideuterons using data collected during four BESS balloon flights from 1997 to 2000. No candidate was found. derived, the first time, an upper limit of 1.9 x 10(-4) (m2s sr GeV/nucleon)(-1) differential flux antideuterons, at 95% confidence level, between 0.17 and 1.15 GeV/nucleon top atmosphere.
Abstract We have applied sputtering using a buckminsterfullerene (C 60 ) ion beam for XPS analysis. A practical sputter rate of 2.4 nm min −1 SiO 2 was obtained an area 5 mm × kV C with energy 83 eV per carbon atom. Extremely low degradation polytetrafluoroethylene observed in these conditions. The results were compared argon energies 500 V and kV. These are the first utilizing analysis limited damage. Copyright © 2004 John Wiley & Sons, Ltd.