An analysis of atmospheric neutrino data from all four run periods of Super-Kamiokande optimized for sensitivity to the neutrino mass hierarchy is presented. Confidence intervals for Δm322, sin2θ23, ...sin2θ13 and δCP are presented for normal neutrino mass hierarchy and inverted neutrino mass hierarchy hypotheses, based on atmospheric neutrino data alone. Additional constraints from reactor data on θ13 and from published binned T2K data on muon neutrino disappearance and electron neutrino appearance are added to the atmospheric neutrino fit to give enhanced constraints on the above parameters. Over the range of parameters allowed at 90% confidence level, the normal mass hierarchy is favored by between 91.9% and 94.5% based on the combined Super-Kamiokande plus T2K result.
Abstract
KAGRA is a newly built gravitational-wave telescope, a laser interferometer comprising arms with a length of 3 km, located in Kamioka, Gifu, Japan. KAGRA was constructed under the ground and ...it is operated using cryogenic mirrors that help in reducing the seismic and thermal noise. Both technologies are expected to provide directions for the future of gravitational-wave telescopes. In 2019, KAGRA finished all installations with the designed configuration, which we call the baseline KAGRA. For this occasion, we present an overview of the baseline KAGRA from various viewpoints in a series of articles. In this article, we introduce the design configurations of KAGRA with its historical background.
Super-Kamiokande (SK) can search for weakly interacting massive particles (WIMPs) by detecting neutrinos produced from WIMP annihilations occurring inside the Sun. In this analysis, we include ...neutrino events with interaction vertices in the detector in addition to upward-going muons produced in the surrounding rock. Compared to the previous result, which used the upward-going muons only, the signal acceptances for light (few-GeV/c^{2}-200-GeV/c^{2}) WIMPs are significantly increased. We fit 3903 days of SK data to search for the contribution of neutrinos from WIMP annihilation in the Sun. We found no significant excess over expected atmospheric-neutrino background and the result is interpreted in terms of upper limits on WIMP-nucleon elastic scattering cross sections under different assumptions about the annihilation channel. We set the current best limits on the spin-dependent WIMP-proton cross section for WIMP masses below 200 GeV/c^{2} (at 10 GeV/c^{2}, 1.49×10^{-39} cm^{2} for χχ→bbover ¯ and 1.31×10^{-40} cm^{2} for χχ→τ^{+}τ^{-} annihilation channels), also ruling out some fraction of WIMP candidates with spin-independent coupling in the few-GeV/c^{2} mass range.
A search for boosted dark matter using 161.9 kt yr of Super-Kamiokande IV data is presented. We search for an excess of elastically scattered electrons above the atmospheric neutrino background, with ...a visible energy between 100 MeV and 1 TeV, pointing back to the Galactic center or the Sun. No such excess is observed. Limits on boosted dark matter event rates in multiple angular cones around the Galactic center and Sun are calculated. Limits are also calculated for a baseline model of boosted dark matter produced from cold dark matter annihilation or decay. This is the first experimental search for boosted dark matter from the Galactic center or the Sun interacting in a terrestrial detector.
Abstract
KAGRA is a newly built gravitational wave observatory, a laser interferometer with a 3 km arm length, located at Kamioka, Gifu, Japan. In this series of articles we present an overview of ...the baseline KAGRA, for which we finished installing the designed configuration in 2019. This article describes the method of calibration (CAL) used for reconstructing gravitational wave signals from the detector outputs, as well as the characterization of the detector (DET). We also review the physical environmental monitoring (PEM) system and the geophysics interferometer (GIF). Both are used for characterizing and evaluating the data quality of the gravitational wave channel. They play important roles in utilizing the detector output for gravitational wave searches. These characterization investigations will be even more important in the near future, once gravitational wave detection has been achieved, and in using KAGRA in the gravitational wave astronomy era.
Hyper-Kamiokande will be a next-generation underground water Cherenkov detector with a total (fiducial) mass of 0.99 (0.56) million metric tons, approximately 20 (25) times larger than that of ...Super-Kamiokande. One of the main goals of Hyper-Kamiokande is the study of
$CP$
asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams. In this paper, the physics potential of a long-baseline neutrino experiment using the Hyper-Kamiokande detector and a neutrino beam from the J-PARC proton synchrotron is presented. The analysis uses the framework and systematic uncertainties derived from the ongoing T2K experiment. With a total exposure of 7.5 MW
$\times 10^7$
s integrated proton beam power (corresponding to
$1.56 \times 10^{22}$
protons on target with a 30 GeV proton beam) to a
$2.5^\circ$
off-axis neutrino beam, it is expected that the leptonic
$CP$
phase
$\delta _{CP}$
can be determined to better than 19 degrees for all possible values of
$\delta _{CP}$
, and
$CP$
violation can be established with a statistical significance of more than
$3\,\sigma$
(
$5\,\sigma$
) for
$76{\%}$
(
$58{\%}$
) of the
${\delta _{CP}}$
parameter space. Using both
$\nu _e$
appearance and
$\nu _\mu$
disappearance data, the expected 1
$\sigma$
uncertainty of
$\sin ^2\theta _{23}$
is 0.015(0.006) for
$\sin ^2\theta _{23}=0.5(0.45)$
.
We report an indication that the elastic scattering rate of solar B8 neutrinos with electrons in the Super-Kamiokande detector is larger when the neutrinos pass through Earth during nighttime. We ...determine the day-night asymmetry, defined as the difference of the average day rate and average night rate divided by the average of those two rates, to be -3.2 ± 1.1(stat) ± 0.5(syst)%, which deviates from zero by 2.7 σ. Since the elastic scattering process is mostly sensitive to electron-flavored solar neutrinos, a nonzero day-night asymmetry implies that the flavor oscillations of solar neutrinos are affected by the presence of matter within the neutrinos' flight path. Super-Kamiokande's day-night asymmetry is consistent with neutrino oscillations for 4 × 10(-5) eV(2) ≤ Δm 2(21) ≤ 7 × 10(-5) eV(2) and large mixing values of θ12, at the 68% C.L.
Overview of KAGRA: KAGRA science Akutsu, T; Arai, K; Aritomi, N ...
Progress of theoretical and experimental physics,
05/2021, Letnik:
2021, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Abstract
KAGRA is a newly build gravitational wave observatory, a laser interferometer with 3 km arm length, located in Kamioka, Gifu, Japan. In this paper, one of a series of articles featuring ...KAGRA, we discuss the science targets of KAGRA projects, considering not only the baseline KAGRA (current design) but also its future upgrade candidates (KAGRA+) for the near to middle term ($\sim$5 years).
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