XXXI International Conference on Neutrino Physics and Astrophysics

Observation of distant reactor neutrino in Super-Kamiokande with gadolinium-loaded water

18 Jun 2024, 17:30

2h

Near Aula Magna (U6 building) (University of Milano-Bicocca)

Poster Reactor neutrinos Poster session and reception 1

Speaker

Shota Izumiyama (Tokyo Institute of Technology)

Description

Super-Kamiokande is a large underground water Cherenkov detector for neutrino physics and nucleon decay search in Kamioka, Japan. We upgraded its detector with gadolinium (Gd) in 2020 (SK-Gd) to improve electron antineutrino (${\overline{\nu }}_{\text{e}}$) identification. The higher energy yield from neutron capture of Gd enables the SK trigger system to apply to a lower energy region in ${\overline{\nu }}_{\text{e}}$ search than that in the pure water phase where the previous search had a 9 MeV energy threshold.
Many scintillator experiments have measured reactor antineutrinos well, especially in the KamLAND detector in the long baseline over 100 km. No large-scale water Cherenkov detector succeeded in the long-baseline measurements except for the evidence in the SNO+ experiment.
We conducted electron antineutrino analysis from 4 MeV ${\overline{\nu }}_{\text{e}}$ energy threshold via inverse beta decay in the first Gd phase (0.01% concentration), $536\times 22.5\text{days}\cdot \text{kt}$ exposure from 2020 summer to 2022 summer, and observed reactor neutrino. In this poster, we will show the result of reactor neutrino analysis in the first Gd phase (0.01%) and its status in the second Gd phase (0.03%). In addition, we will discuss the application of reactor neutrino measurement in SK-Gd.

Presentation materials

neutrino2024-poster-izumiyama.pdf