T. Yokozawa
A5079004585- Pulsars and Gravitational Waves Research
- Neutrino Physics Research
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Geophysics and Sensor Technology
- Seismic Waves and Analysis
- Geophysics and Gravity Measurements
- High-pressure geophysics and materials
- Astrophysical Phenomena and Observations
- Dark Matter and Cosmic Phenomena
- Radiation Detection and Scintillator Technologies
- Superconducting Materials and Applications
- Seismology and Earthquake Studies
- Cosmology and Gravitation Theories
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Magnetic confinement fusion research
- Meteorological Phenomena and Simulations
- Advanced Frequency and Time Standards
- Seismic Imaging and Inversion Techniques
- Radio Astronomy Observations and Technology
- Robotics and Automated Systems
- Advanced Electrical Measurement Techniques
- Parasitic infections in humans and animals
Kavli Institute for the Physics and Mathematics of the Universe
2016-2024
The University of Tokyo
2014-2024
Niigata University
2024
Rakuno Gakuen University
2024
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso
2021
Gran Sasso Science Institute
2021
National Astronomical Observatory of Japan
2020
University of Toyama
2020
Osaka City University
2014-2018
Tsinghua University
2009
The results of the third phase Super-Kamiokande solar neutrino measurement are presented and compared to first second results. With improved detector calibrations, a full simulation, analysis methods, systematic uncertainty on total flux is estimated be ?2.1%, which about two thirds for Super-Kamiokande. observed 8B in 5.0 20 MeV electron energy region 2.32+/-0.04 (stat.)+/-0.05 (sys.) *10^6 cm^-2sec^-1, agreement with previous measurements. A combined oscillation carried out using SK-I, II,...
After important upgrades to the experiment, Super-Kamiokande collaboration returns measuring solar mixing angle and mass splitting $\mathrm{\ensuremath{\Delta}}\phantom{\rule{0}{0ex}}{m}_{12}^{2}$. By focusing on low-energy ${}^{8}B$ neutrinos, is able single out neutrinos that undergo flavor conversion only through vacuum oscillations. The results are currently most precise values for mass-difference parameters relevant neutrino
A new Super-Kamiokande (SK) search for Supernova Relic Neutrinos (SRNs) was conducted using 2853 live days of data. Sensitivity is now greatly improved compared to the 2003 SK result, which placed a flux limit near many theoretical predictions. This more detailed analysis includes variety improvements such as increased efficiency, lower energy threshold, and an expanded data set. New combined upper limits on SRN are between 2.8 3.0 nu_e cm^-2 s^-1 > 16 MeV total positron (17.3 E_nu).
Are there more than three types of neutrinos in nature ? Some experiments show that should exist at least one type, called sterile neutrinos. Using atmospheric neutrino data from the Super-Kamiokande experiment, authors find new limits on oscillations.
We have searched for proton decay via $p \rightarrow \nu K^{+}$ using Super-Kamiokande data from April 1996 to February 2013, 260 kiloton$\cdot$year exposure in total. No evidence this mode is found. A lower limit of the lifetime set $5.9 \times 10^{33}$ years at 90% confidence level.
We report an indication that the elastic scattering rate of solar $^8$B neutrinos with electrons in Super-Kamiokande detector is larger when pass through Earth during nighttime. determine day/night asymmetry, defined as difference average day and night divided by those two rates, to be $(-3.2\pm1.1(\text{stat})\pm0.5(\text{syst}))\%$, which deviates from zero 2.7 $\sigma$. Since process mostly sensitive electron-flavored neutrinos, a non-zero asymmetry implies flavor oscillations are...
Super-Kamiokande atmospheric neutrino data were fit with an unbinned maximum likelihood method to search for the appearance of tau leptons resulting from interactions oscillation-generated neutrinos in detector. Relative expectation unity, normalization is found be 1.42 ± 0.35(stat)(-0.12)(+0.14)(syst) excluding no-tau-appearance hypothesis, which would zero, at 3.8σ level. We estimate that 180.1 44.3(stat)(-15.2)(+17.8) (syst) produced 22.5 kton fiducial volume detector by during 2806 day...
We present a search for differences in the oscillations of antineutrinos and neutrinos Super-Kamiokande-I, -II, -III atmospheric neutrino sample. Under two-flavor disappearance model with separate mixing parameters between antineutrinos, we find no evidence difference oscillation parameters. Best-fit antineutrino is found to be at (Δm2,sin2 2θ)=(2.0×10(-3) eV2, 1.0) consistent overall Super-K measurement.
A search for neutrino oscillations induced by Lorentz violation has been performed using 4,438 live-days of Super-Kamiokande atmospheric data. The is included in addition to standard three-flavor the nonperturbative model extension (SME), allowing use full range path lengths, ranging from 15 12,800 km, and energies 100 MeV more than TeV search. No evidence was observed, so limits are set on renormalizable isotropic SME coefficients eμ, μτ, eτ sectors, improving existing up 7 orders magnitude...
We present the results of searches for nucleon decay via bound neutron to antineutrino plus pizero and proton piplus using data from a combined 172.8 kiloton-years exposure Super-Kamiokande-I, -II, -III. set lower limits on partial lifetime each these modes. For pizero, is >1.1x10^{33} years; piplus, >3.9x10^{32} years at 90% confidence level.
Used for both proton decay searches and neutrino physics, large water Cherenkov (WC) detectors have been very successful tools in particle physics. They are notable their masses charged detection capabilities. While current WC reconstruct tracks over a wide energy range, they cannot efficiently detect neutrons. Gadolinium (Gd) has the largest thermal neutron capture cross section of all stable nuclei produces an 8 MeV gamma cascade that can be detected with high efficiency. Because many new...
We present a search for an excess of neutrino interactions due to dark matter in the form weakly interacting massive particles (WIMPs) annihilating Galactic center or halo based on data set Super-Kamiokande-I, -II, -III and -IV taken from 1996 2016. model flux, energy, flavor distributions assuming WIMP self-annihilation is dominant $\ensuremath{\nu}\overline{\ensuremath{\nu}}$, ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, $b\overline{b}$, ${W}^{+}{W}^{\ensuremath{-}}$. The...
We have searched for proton into muon plus neutral kaon using data from a 91.7 kiloton-year exposure of Super-Kamiokande-I, 49.2 Super-Kamiokande-II, and 31.9 Super-Kamiokande-III. The number candidate events in the was consistent with atmospheric neutrino background expectation no evidence decay this mode found. set partial lifetime lower limit 1.6x10^33 years at 90% confidence level.
The Super-Kamiokande detector is a ring imaging Cherenkov for neutrino physics and proton-decay search consists of 50 000 tons pure water equipped with about 13 photo-multipliers. old front-end electronics online system running more than one decade were all upgraded in September, 2008 the data acquisition was started successfully. new based on charge to time converter multi-hit Time Digital converter. TCP/IP readout channel implemented handle large amounts data. In scheme, hardware...
The next time a core-collapse supernova (SN) explodes in our galaxy, vari- ous detectors will be ready and waiting to detect its emissions of gravitational waves (GWs) neutrinos. Current numerical simulations have successfully introduced multi-dimensional effects produce exploding SN models, but thus far the explosion mechanism is not well understood. In this paper, we focus on an investigation progenitor core rotation via comparison start GW emission that neutronization burst. neutrino de-...
In the data obtained by laser interferometric gravitational wave detectors, transient noise with non-stationary and non-Gaussian features occurs at a high rate. This often results in problems such as detector instability hiding and/or imitation of gravitational-wave signals. has various characteristics time-frequency representation, which is considered to be associated environmental instrumental origins. Classification can offer clues for exploring its origin improving performance detector....
The trilepton nucleon decay modes p→e+νν and p→μ+νν violate |Δ(B-L)| by two units. Using data from a 273.4 kt yr exposure of Super-Kamiokande search for these decays yields fit consistent with no signal. Accordingly, lower limits on the partial lifetimes τp→e+νν>1.7×10(32) years τp→μ+νν>2.2×10(32) at 90% confidence level are obtained. These can constrain Grand Unified Theories which allow such processes.
The absolute accuracy of the estimated parameters gravitational wave sources will be fundamentally limited by calibration uncertainties detectors in upcoming observation runs with increased number source statistics. Photon calibrators have so far been primary tools for a test-mass displacement, relying on measurement photon pressure. current technological limit uncertainty gravitational-wave amplitudes is to few percent, due laser power standard maintained metrology institutes. To reduce...
The KAGRA gravitational-wave detector in Japan is the only operating hosted an underground infrastructure. Underground sites promise a greatly reduced contribution of environment to noise thereby opening possibility extend observation band frequencies well below 10 Hz. For this reason, proposed next-generation infrastructure Einstein Telescope Europe would be realized aiming for that extends from 3 Hz several kHz. However, it known ambient low-frequency - 20 at current surface Virgo and LIGO...
We present the development of neutron-tagging techniques in Super-Kamiokande IV using a neural network analysis. The detection efficiency neutron capture on hydrogen is estimated to be 26%, with mis-tag rate 0.016 per neutrino event. uncertainty tagging 9.0%. Measurement data from an Americium-Beryllium calibration agrees this value within 10%. procedure was performed 3,244.4 days SK-IV atmospheric data, identifying 18,091 neutrons 26,473 events. fitted lifetime measured as 218 \pm 9 \mu s.
Abstract In this study, we detected the horizontal ground strains induced by atmospheric Lamb wave emitted from 2022 eruption of Tonga–Hunga Ha’apai undersea volcano, at an underground observatory in Kamioka, Japan. The observed were range $${10}^{-11}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mo>-</mml:mo> <mml:mn>11</mml:mn> </mml:msup> </mml:math> – $${10}^{-10}$$ and measured precisely using a 1500-m laser...