Engineering topics
Abe, K.
Publications and source records attributed to Abe, K..
Measurement of Coherent π + Production in Low Energy Neutrino-Carbon Scattering
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SEARCH FOR NEUTRINOS IN SUPER-KAMIOKANDE ASSOCIATED WITH GRAVITATIONAL-WAVE EVENTS GW150914 AND GW151226
We report the results from a search in Super-Kamiokande for neutrino signals coincident with the first detected gravitational-wave events, GW150914 and GW151226, as well as LVT151012, using a neutrino energy range from 3.5 MeV to 100 PeV. We searched for coincident neutrino events within a time window of ±500 s around the gravitational-wave detection time. Four neutrino candidates are found for GW150914, and no candidates are found for GW151226. The remaining neutrino candidates are consistent with the expected background events. We calculated the 90% confidence level upper limits on the combined neutrino fluence for both gravitational-wave events, which depends on event energy and topologies. Considering the upward-going muon data set (1.6 GeV–100 PeV), the neutrino fluence limit for each gravitational-wave event is 14–37 (19–50) cm{sup −2} for muon neutrinos (muon antineutrinos), depending on the zenith angle of the event. In the other data sets, the combined fluence limits for both gravitational-wave events range from 2.4 × 10{sup 4} to 7.0 × 10{sup 9} cm{sup −2}.
Solar neutrino measurements in Super-Kamiokande-IV
We report that upgraded electronics, improved water system dynamics, better calibration and analysis techniques allowed Super-Kamiokande-IV to clearly observe very low-energy B 8 solar neutrino interactions, with recoil electron kinetic energies as low as ~ 3.5 MeV . Super-Kamiokande-IV data-taking began in September of 2008; this paper includes data until February 2014, a total livetime of 1664 days. The measured solar neutrino flux is ( 2.308 ± 0.020 ( stat ) - 0.040 + 0.039 ( syst ) ) × 1 0 6 / ( cm 2 sec ) assuming no oscillations. The observed recoil electron energy spectrum is consistent with no distortions due to neutrino oscillations. An extended maximum likelihood fit to the amplitude of the expected solar zenith angle variation of the neutrino-electron elastic scattering rate in SK-IV results in a day/night asymmetry of ( - 3.6 ± 1.6 ( stat ) ± 0.6 ( syst ) ) % . The SK-IV solar neutrino data determine the solar mixing angle as sin 2 θ 12 = 0.327 - 0.031 + 0.026 , all SK solar data (SK-I, SK-II, SK III and SK-IV) measures this angle to be sin 2 θ 12 = 0.334 - 0.023 + 0.027 , the determined mass-squared splitting is Δ m 21 2 = 4.8 - 0.8 + 1.5 × 10 - 5 eV 2 .
MEASUREMENTS OF COSMIC-RAY PROTON AND HELIUM SPECTRA FROM THE BESS-POLAR LONG-DURATION BALLOON FLIGHTS OVER ANTARCTICA
The BESS-Polar Collaboration measured the energy spectra of cosmic-ray protons and helium during two long-duration balloon flights over Antarctica in 2004 December and 2007 December at substantially different levels of solar modulation. Proton and helium spectra probe the origin and propagation history of cosmic rays in the galaxy, and are essential to calculations of the expected spectra of cosmic-ray antiprotons, positrons, and electrons from interactions of primary cosmic-ray nuclei with the interstellar gas, and to calculations of atmospheric muons and neutrinos. We report absolute spectra at the top of the atmosphere for cosmic-ray protons in the kinetic energy range 0.2–160 GeV and helium nuclei in the range 0.15–80 GeV/nucleon. The corresponding magnetic-rigidity ranges are 0.6–160 GV for protons and 1.1–160 GV for helium. These spectra are compared to measurements from previous BESS flights and from ATIC-2, PAMELA, and AMS-02. We also report the ratio of the proton and helium fluxes from 1.1 to 160 GV and compare this to the ratios from PAMELA and AMS-02.