N. Sakurai
A5044924730- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Neutrino Physics Research
- High-Energy Particle Collisions Research
- Particle Detector Development and Performance
- Radio Astronomy Observations and Technology
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Quantum Chromodynamics and Particle Interactions
- Atmospheric Ozone and Climate
- Atomic and Subatomic Physics Research
- Lightning and Electromagnetic Phenomena
- Calibration and Measurement Techniques
- Particle Accelerators and Free-Electron Lasers
- Ionosphere and magnetosphere dynamics
- Radiation Detection and Scintillator Technologies
- Scientific Research and Discoveries
- Astronomical Observations and Instrumentation
- Computational Physics and Python Applications
- Cosmology and Gravitation Theories
- Radio, Podcasts, and Digital Media
- Advanced Semiconductor Detectors and Materials
- Microbial bioremediation and biosurfactants
- Metal-Catalyzed Oxygenation Mechanisms
Tokushima University
2017-2024
Osaka Sangyo University
2024
Osaka Metropolitan University
2023-2024
Tokyo Metropolitan University
2023-2024
The University of Tokyo
2002-2023
Institute of Physics, Academia Sinica
2023
Osaka City University
2012-2021
University of Utah
2019-2021
Institute for Cosmic Ray Research
2021
Kanagawa University
2016-2017
We present an analysis of atmospheric neutrino data from a 33.0 kton yr (535-day) exposure the Super-Kamiokande detector. The exhibit zenith angle dependent deficit muon neutrinos which is inconsistent with expectations based on calculations flux. Experimental biases and uncertainties in prediction fluxes cross sections are unable to explain our observation. consistent, however, two-flavor...
Solar neutrino measurements from 1258 days of data the Super-Kamiokande detector are presented. The based on recoil electrons in energy range 5.0--20.0 MeV. measured solar flux is $2.32\ifmmode\pm\else\textpm\fi{}0.03(\mathrm{stat}{)}_{\ensuremath{-}0.07}^{+0.08}(\mathrm{syst})\ifmmode\times\else\texttimes\fi{}{10}^{6}{\mathrm{cm}}^{\ensuremath{-}2}{\mathrm{s}}^{\ensuremath{-}1}$, which $45.1\ifmmode\pm\else\textpm\fi{}0.5(\mathrm{stat}{)}_{\ensuremath{-}1.4}^{+1.6}(\mathrm{syst})%$ that...
The K2K experiment observes indications of neutrino oscillation: a reduction $\nu_\mu$ flux together with distortion the energy spectrum. Fifty-six beam events are observed in Super-Kamiokande (SK), 250 km from production point, an expectation $80.1^{+6.2}_{-5.4}$. Twenty-nine one ring $\mu$-like used to reconstruct spectrum, which is better matched expected spectrum oscillation than without. probability that at SK explained by statistical fluctuation without less 1%.
The first results of the solar neutrino flux measurement from Super-Kamiokande are presented. shown here obtained data taken between 31 May 1996, and 23 June 1997. Using our recoil electrons with energies above 6.5 MeV, we infer total ${}^{8}\mathrm{B}$ neutrinos to be $2.42\ifmmode\pm\else\textpm\fi{}0.06(\mathrm{stat}{)}_{\ensuremath{-}0.07}^{+0.10}(\mathrm{syst})\ifmmode\times\else\texttimes\fi{}{10}^{6}\mathrm{cm}{}^{\ensuremath{-}2}{\mathrm{s}}^{\ensuremath{-}1}$. This result is...
The previously published atmospheric neutrino data did not distinguish whether muon neutrinos were oscillating into tau or sterile neutrinos, as both hypotheses fit the data. Using recorded in 1100 live days of Super-Kamiokande detector, we use three complementary samples to study difference zenith angle distribution due neutral currents and matter effects. We find no evidence favoring reject hypothesis at 99% confidence level. On other hand, that oscillation between suffices explain all...
We report the result of a search for neutrino oscillations using precise measurements recoil electron energy spectrum and zenith angle variations solar flux from 1258 days neutrino-electron scattering data in Super-Kamiokande. The absence significant variation distortion places strong constraints on mixing mass difference flux-independent way. Using Super-Kamiokande measurement addition, two allowed regions at large are found.Received 19 March...
A total of 614 upward throughgoing muons minimum energy 1.6 GeV are observed by Super-Kamiokande during 537 detector live days. The measured muon flux is [1.74±0.07(stat)±0.02(sys)]×10−13cm−2s−1sr−1 compared to an expected [1.97±0.44(theor)]×10−13cm−2s−1sr−1. absolute in agreement with the prediction within errors. However, zenith-angle dependence does not agree no-oscillation predictions. distortion shape consistent νμ↔ντ oscillation hypothesis sin22θ>0.4 and 1×10−3<Δm2<1×10−1eV2 at 90%...
From an exposure of 25.5 kiloton-years the Super-Kamiokande detector, 900 muon-like and 983 electron-like single-ring atmospheric neutrino interactions were detected with momentum pe>100 MeV/c, pμ>200 visible energy less than 1.33 GeV. Using a detailed Monte Carlo simulation, ratio (μ/e)DATA/(μ/e)MC was measured to be 0.61±0.03(stat.)±0.05(sys.), consistent previous results from Kamiokande, IMB Soudan-2 experiments, smaller expected theoretical models production.
The details of Super-Kamiokande-I’s solar neutrino analysis are given. Solar measurement in Super-Kamiokande is a high statistics collection 8B neutrinos via neutrino-electron scattering. method and results the 1496 day data sample presented. final oscillation for presented also.50 MoreReceived 30 August 2005DOI:https://doi.org/10.1103/PhysRevD.73.112001©2006 American Physical Society
The flavor ratio of the atmospheric neutrino flux and its zenith angle dependence have been studied in multi-GeV energy range using an exposure 25.5 kiloton-years Super-Kamiokande detector. By comparing data to a detailed Monte Carlo simulation, (μ/e)DATA/(μ/e)MC was measured be 0.66±0.06(stat.)±0.08(sys.). In addition, strong distortion shape μ-like event distribution observed. number upward downward events found 0.52+0.07−0.06(stat.)±0.01(sys.), with expected value...
The Telescope Array (TA) experiment, located in the western desert of Utah,USA, is designed for observation extensive air showers from extremely high energy cosmic rays. experiment has a surface detector array surrounded by three fluorescence detectors to enable simultaneous detection shower particles at ground level and photons along track. TA started full hybrid March, 2008. In this article we describe design technical features detector.
We have searched for intermediate-scale anisotropy in the arrival directions of ultrahigh-energy cosmic rays with energies above 57~EeV northern sky using data collected over a 5 year period by surface detector Telescope Array experiment. report on cluster events that we call hotspot, found oversampling 20$^\circ$-radius circles. The hotspot has Li-Ma statistical significance 5.1$\sigma$, and is centered at R.A.=146.7$^{\circ}$, Dec.=43.2$^{\circ}$. position about 19$^{\circ}$ off...
The Telescope Array (TA) collaboration has measured the energy spectrum of ultra-high cosmic rays with primary energies above 1.6 x 10^(18) eV. This measurement is based upon four years observation by surface detector component TA. shows a dip at an 4.6 eV and steepening 5.4 10^(19) which consistent expectation from GZK cutoff. We present results technique, new to analysis ray data, that involves generating complete simulation striking TA detector. procedure starts shower simulations using...
A search for day-night variations in the solar neutrino flux resulting from oscillations has been carried out using 504 day sample of data obtained at Super-Kamiokande. The absence a significant variation set an absolute independent exclusion region two oscillation parameter space.
A measurement of the energy spectrum recoil electrons from solar neutrino scattering in Super-Kamiokande detector is presented. The results shown here were obtained 504 days data taken between 31 May 1996 and 25 March 1998. shape measured compared with expectation for ${}^{8}\mathrm{B}$ neutrinos. comparison takes into account both kinematic related effects process. spectral observation gives a ${\ensuremath{\chi}}^{2}$ 25.3 15 degrees freedom, corresponding to $4.6%$ confidence level.
We present the results of indirect searches for Weakly Interacting Massive Particles (WIMPs), with 1679.6 live days data from Super-Kamiokande detector using neutrino-induced upward through-going muons. The search is performed by looking an excess high energy muon neutrinos WIMP annihilations in Sun, core Earth, and Galactic Center, as compared to number expected atmospheric neutrino background. No statistically significant was seen. calculate flux limits various angular cones around each...
A search for the relic neutrinos from all past core-collapse supernovae was conducted using 1496 days of data Super-Kamiokande detector. This analysis looked electron-type antineutrinos that had produced a positron with an energy greater than 18 MeV. In absence signal, 90% C.L. upper limits on total flux were set several theoretical models; these ranged 20 to 130 macro nu(e) cm(-2) s(-1). Additionally, bound 1.2 s(-1) supernova neutrino in region E(nu)>19.3
The time variation of the elastic scattering rate solar neutrinos with electrons in Super-Kamiokande-I was fit to variations expected from active two-neutrino oscillations. best large mixing angle solution has a tan2θ=0.55 and mass squared difference Δm2=6.3×10−5eV2 between two neutrino eigenstates. fitted day-night asymmetry −1.8±1.6(stat)+1.3−1.2(syst)% improved statistical precision over previous measurements agrees well −2.1%.Received 4 September...
We report on a measurement of the cosmic ray energy spectrum by Telescope Array Low-Energy Extension (TALE) air fluorescence detector. The TALE detector is also sensitive to Cherenkov light produced shower particles. Low rays, in PeV range, are detectable as "Cherenkov Events". Using these events, we measure from low $\sim 2$ an greater than 100 PeV. Above can detect rays using fluorescence. This allows for extension energies few EeV. In this paper, will describe detector, explain technique,...
The differential cross sections for inclusive neutral pions as a function of transverse and longitudinal momentum in the very forward rapidity region have been measured at Large Hadron Collider (LHC) with detector (LHCf) proton-proton collisions $\sqrt{s}=$ 2.76 7 TeV proton-lead nucleon-nucleon center-of-mass energies $\sqrt{s_\text{NN}}=$ 5.02 TeV. Such are compatible hypotheses limiting fragmentation Feynman scaling. Comparing collisions, we find sizable suppression production after...