2022/11/15 by Sakuda, Makoto, Suzuki, Toshio, Reen, Mandeep Singh +2
#FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th)
paper · doi:10.48550/arxiv.2211.07851
We first discuss and determine the isospin mixing of the two 2- states (12.53 MeV and 12.97 MeV) of 16O nucleus using the inelastic electron scattering data. We then evaluate the cross section of 4.4-MeV γ rays produced in the neutrino neutral-current (NC) reaction 16O(ν, ν′)16O(12.97 \rm MeV, 2-) in a water Cherenkov detector at the low energy below 100 MeV. The detection of γ rays for Eγ>5 MeV from the NC reaction 16O(ν, ν′)16O(Ex>16 \rm MeV, T=1) with a water Cherenkov detector in the supernova neutrino bursts has been proposed and discussed by several authors previously. In this article, we discuss a new NC reaction channel from 16O(12.97 \rm MeV, 2-) producing a 4.4-MeV γ ray, the cross section of which is more robust and even larger at the low energy (Eν<25 MeV) than the NC cross section from 16O(Ex>16 \rm MeV, T=1). We also evaluate the number of such events induced by neutrinos from supernova explosion which can be observed by the Super-Kamiokande, a 32 kton water Cherenkov detector in the Earth.