Kazuyoshi Kobayashi
A5103202356- Dark Matter and Cosmic Phenomena
- Astrophysics and Cosmic Phenomena
- Neutrino Physics Research
- Particle physics theoretical and experimental studies
- Spinal Fractures and Fixation Techniques
- Spine and Intervertebral Disc Pathology
- Scoliosis diagnosis and treatment
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Cervical and Thoracic Myelopathy
- Musculoskeletal pain and rehabilitation
- Nutrition and Health in Aging
- Body Composition Measurement Techniques
- Intraoperative Neuromonitoring and Anesthetic Effects
- Spinal Hematomas and Complications
- Cerebral Palsy and Movement Disorders
- Cosmology and Gravitation Theories
- Bone Tumor Diagnosis and Treatments
- Radio Astronomy Observations and Technology
- Bone health and osteoporosis research
- Neurofibromatosis and Schwannoma Cases
- Cancer Mechanisms and Therapy
- Chromatin Remodeling and Cancer
- Meningioma and schwannoma management
- Gamma-ray bursts and supernovae
Japan Aerospace Exploration Agency
2021-2024
Institute of Space and Astronautical Science
2024
Waseda University
2003-2023
Ibaraki National College of Technology
2023
National Institute of Technology, Kagoshima College
2023
Hitachi (Japan)
2023
University of Pisa
2023
University of Maryland, College Park
2023
Physical Sciences (United States)
2023
Japanese Red Cross Nagoya Daini Hospital
2022-2023
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%.
We present a combined analysis of fully-contained, partially-contained and upward-going muon atmospheric neutrino data from 1489 d exposure the Super-Kamiokande detector. The samples span roughly five decades in energy, 100 MeV to 10 TeV. A detailed Monte Carlo comparison is described presented. fit expectation, found be consistent with oscillations ${\ensuremath{\nu}}_{\ensuremath{\mu}}\ensuremath{\leftrightarrow}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ ${sin}^{2}2\ensuremath{\theta}>0.92$...
Minocycline is commonly used to inhibit microglial activation. It widely accepted that activated microglia exert dual functions, is, pro-inflammatory (M1) and anti-inflammatory (M2) functions. The in vivo status of probably on a continuum between these two extreme states. However, the mechanisms regulating polarity remain elusive. Here, we addressed this question focusing minocycline. We SOD1G93A mice as model, which exhibit motor neuron-specific neurodegenerative disease, amyotrophic...
We present measurements of nu_mu disappearance in K2K, the KEK to Kamioka long-baseline neutrino oscillation experiment. One hundred and twelve beam-originated events are observed fiducial volume Super-Kamiokande with an expectation 158.1^{+9.2}_{-8.6} without oscillation. A distortion energy spectrum is also seen 58 single-ring muon-like reconstructed energies. The probability that observations explained by for no 0.0015% (4.3sigma). In a two flavor scenario, allowed Delta m^2 region at...
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...
Muon neutrino disappearance probability as a function of flight length L over energy E was studied. A dip in the L/E distribution observed data, predicted from sinusoidal flavor transition oscillation. The constrained nu_mu <-> nu_tau oscillation parameters; 1.9x10^-3 < Delta m^2 3.0x10^-3 eV^2 and \sin^2(2theta) > 0.90 at 90% confidence level.
We present results for ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ oscillation in the KEK to Kamioka (K2K) long-baseline neutrino experiment. K2K uses an accelerator-produced beam with a mean energy of 1.3 GeV directed at Super-Kamiokande detector. observed energy-dependent disappearance ${\ensuremath{\nu}}_{\ensuremath{\mu}}$, which we presume have oscillated ${\ensuremath{\nu}}_{\ensuremath{\tau}}$. The probability that would observe these if there is no 0.0050% ($4.0\ensuremath{\sigma}$).
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 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,...
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 present a search for non-zero theta_{13} and deviations of sin^2 theta_{23} from 0.5 in the oscillations atmospheric neutrino data Super-Kamiokande -I, -II, -III. No distortions flux consistent with are found both mass hierarchy hypotheses agreement data. The best fit at Delta m^2 = 2.1 x 10^-3 eV^2, 0.0, =0.5. In normal (inverted) constrained one-dimensional 90% C.L. to < 0.04 (0.09) 1.9 (1.7) 2.6 (2.7) eV^2. mixing angle is within 0.407 <= 0.583
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...
The weak nucleon axial-vector form factor for quasi-elastic interactions is determined using neutrino interaction data from the K2K Scintillating Fiber detector in beam at KEK. More than 12,000 events are analyzed, of which half charged-current nu-mu n to mu- p occurring primarily oxygen nuclei. We use a relativistic Fermi gas model and assume approximately dipole with one parameter, axial vector mass M_A, fit shape distribution square momentum transfer nucleus. Our best result M_A = 1.20...