K. Iwamoto
A5106267274- Neutrino Physics Research
- Particle physics theoretical and experimental studies
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Muon and positron interactions and applications
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Nuclear Physics and Applications
- Pulsars and Gravitational Waves Research
- Particle accelerators and beam dynamics
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astrophysical Phenomena and Observations
- Noncommutative and Quantum Gravity Theories
- Atomic and Subatomic Physics Research
- Plant Reproductive Biology
- Plant Stress Responses and Tolerance
- Rare-earth and actinide compounds
- Magnetic Properties of Alloys
- Plant Molecular Biology Research
- High-pressure geophysics and materials
- Quantum Chromodynamics and Particle Interactions
The University of Tokyo
1998-2024
Okayama University
2023
University of Rochester
2014-2017
Nihon University
1999-2001
Tokyo University of Science
1995-1998
T2K reports its first results in the search for CP violation neutrino oscillations using appearance and disappearance channels neutrino- antineutrino-mode beams. The data include all runs from January 2010 to May 2016 comprise 7.482×10^{20} protons on target mode, which yielded far detector 32 e-like 135 μ-like events, 7.471×10^{20} antineutrino 4 66 events. Reactor measurements of sin^{2}2θ_{13} have been used as an additional constraint. one-dimensional confidence interval at 90% phase...
The T2K experiment reports updated measurements of neutrino and antineutrino oscillations using both appearance disappearance channels. This result comes from an exposure $14.9(16.4)\ifmmode\times\else\texttimes\fi{}1{0}^{20}$ protons on target in (antineutrino) mode. Significant improvements have been made to the interaction model far detector reconstruction. An extensive set simulated data studies also performed quantify effect uncertainties oscillation parameter sensitivity. performs...
view Abstract Citations (143) References (27) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Theoretical Light Curves for the Type IC Supernova SN 1994I Iwamoto, Kohichi ; Nomoto, Ken'ichi Höflich, Peter Yamaoka, Hitoshi Kumagai, Shiomi Shigeyama, Toshikazu in M 51 has provided light curves various wavelength bands allowing a distinction between models of Ic supernovae. We present bolometric and monochromatic exploding C+O stars that form from ~13-15 M_sun_...
T2K measured the neutrino mass difference $\ensuremath{\delta}\phantom{\rule{0}{0ex}}{m}_{32}^{2}$ and mixing angle ${\ensuremath{\theta}}_{23}$ both for neutrinos and, separately, anti-neutrinos. Their results are not only highly competitive, but, since they show no in these two modes, provide important evidence that CPT is violated within accuracy of their measurements.
We propose and validate a method of antineutrino energy reconstruction for charged-current meson-less interactions on composite fully active targets containing hydrogen (such as hydrocarbon scintillator), which is largely free the poorly understood nuclear effects that usually distort bias attempts to measure neutrino energy. The based precise event-by-event measurement outgoing neutron kinetic subsequent assessment momentum imbalance plane transverse incoming direction. For an flux peaked...
To understand the regulatory mechanisms of brassinosteroid (BR) biosynthesis in specific plant developmental processes, we first investigated accumulation profiles BRs and sterols xylem differentiation a Zinnia culture. The amounts many substances late C28 sterol biosynthetic pathway to campesterol (CR), such as episterol 24-methylenecholesterol, well those BR-specific from CR brassinolide (BL), were elevated close association with tracheary element differentiation. Among them,...
Sterile neutrinos - that do not directly participate in weak interactions remain a vibrant possibility could resolve number of anomalies observed neutrino experiments. The T2K Collaboration's latest analysis tests the hypothesis single light sterile neutrino. negative results their search set strongest limits to date on mass splitting and mixing angle probed by long baseline experiment.
view Abstract Citations (68) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Type II Supernovae from 8--10 Msun Asymptotic Giant Branch Stars Hashimoto, Masaaki ; Iwamoto, Kohichi Nomoto, Ken'ichi The final evolution of 8-10 M_sun_ stars in the AGB phase is recalculated to clarify whether these undergo collapse or thermonuclear explosion. New electron capture rates based on shell model wave functions are employed for degenerate O + Ne Mg core....
We report a measurement of the flux-integrated cross section for inclusive muon neutrino charged-current interactions on carbon. The double-differential measurements are given as function momentum and angle. Relative to our previous publication this topic, these results have an increased angular acceptance higher statistics. data sample presented here corresponds $5.7\ifmmode\times\else\texttimes\fi{}{10}^{20}$ protons target. total is measured be...
In order to extract neutrino oscillation parameters, precision long-baseline experiments rely on detailed models of interactions with nuclei. These constitute an important source systematic uncertainty, partially because detectors date have been blind final state neutrons. Three-dimensional projection scintillator trackers comprise components the near next generation experiments. Due good timing resolution and fine granularity, this technology is capable measuring neutron kinetic energy in...
Rayleigh-Taylor (R-T) instabilities in the explosion of SN 1993J are investigated by means two-dimensional hydrodynamical simulations. It is found that extent mixing sensitive to progenitor's core mass and envelope mass. Because helium (3-4 M☉) smaller than 1987A, R-T at He/C+O interface develop induce a large-scale core, while instability relatively weak H/He as result small The predicted abundance distributions, particular 56Ni mixing, compared with those required modeling bolometric light...
We report a measurement of the ${\ensuremath{\nu}}_{\ensuremath{\mu}}$-nucleus inclusive charged-current cross section ($={\ensuremath{\sigma}}^{cc}$) on iron using data from INGRID detector exposed to J-PARC neutrino beam. The consists 14 modules in total, which are spread over range off-axis angles 0\ifmmode^\circ\else\textdegree\fi{} 1.1\ifmmode^\circ\else\textdegree\fi{}. variation energy spectrum as function angle, combined with event topology information, is used calculate this energy....
Neutrino neutral-current induced single photon production is a sub-leading order process for accelerator-based neutrino beam experiments including T2K. It is, however, an important to understand because it background electron (anti)neutrino appearance oscillation experiments. Here, we performed the first search of this below 1 GeV using fine-grained detector at T2K ND280 off-axis near detector. By reconstructing kinematics from electron-positron pairs, achieved 95\% pure gamma ray sample...
We report measurements by the T2K experiment of parameters ${\ensuremath{\theta}}_{23}$ and $\mathrm{\ensuremath{\Delta}}{m}_{32}^{2}$, which govern disappearance muon neutrinos antineutrinos in three-flavor PMNS neutrino oscillation model at T2K's energy propagation distance. Utilizing ability to run with either a mainly or antineutrino beam, muon-like events from each beam mode are used measure these separately for oscillations. Data taken $1.49\ifmmode\times\else\texttimes\fi{}{10}^{21}$...
A novel scintillator detector, the SuperFGD, has been selected as main neutrino target for an upgrade of T2K experiment ND280 near detector. The detector design will allow nearly 4{\pi} coverage interactions at and provide lower energy thresholds, significantly reducing systematic errors experiment. SuperFGD is made optically-isolated cubes size 10x10x10 mm^3, providing required spatial resolution to reduce uncertainties future runs. have close two million in a 1920x560x1840 mm^3 volume....
We report a measurement of cross section $\sigma(\nu_{\mu}+{\rm nucleus}\rightarrow\mu^{-}+X)$ and the first measurements $\sigma(\bar{\nu}_{\mu}+{\rm nucleus}\rightarrow\mu^{+}+X)$ their ratio $R(\frac{\sigma(\bar \nu)}{\sigma(\nu)})$ at (anti-)neutrino energies below 1.5 GeV. determine single momentum bin measurements, averaged over T2K $\bar{\nu}/\nu$-flux, for detector target material (mainly Carbon, Oxygen, Hydrogen Copper) with phase space restricted laboratory frame kinematics...
Abstract We report a measurement of the flux-integrated $\nu_{\mu}$ charged-current cross sections on water, hydrocarbon, and iron in T2K on-axis neutrino beam with mean energy 1.5 GeV. The measured are $\sigma^{\rm{H_{2}O}}_{\rm{CC}} = (0.840\pm 0.010(\mathrm{stat.})^{+0.10}_{-0.08}(\mathrm{syst.}))\times10^{-38}\,\mathrm{cm}^2$/nucleon, $\sigma^{\rm{CH}}_{\rm{CC}} (0.817\pm 0.007(\mathrm{stat.})^{+0.11}_{-0.08}(\mathrm{syst.}))\times10^{-38}\,\mathrm{cm}^2$/nucleon,...
We summarize various explosion models of Type la supernovae and their nucleosynthesis features for both Chandrasekhar sub-Chandrasekhar mass white dwarf models. These provide different predictions the photometric spectroscopic variations among supernovae, which are compared with observations. Some attempts to model peculiar SNe 1991T 1991bg shown.