Analysis of gamma-ray production in neutral-current neutrino-oxygen interactions at energies above 200 MeV

TL;DR

This paper calculates gamma-ray production cross sections in neutrino-oxygen interactions above 200 MeV, using a realistic spectral function model, revealing that about 41% of interactions emit gamma rays above 6 MeV at 600 MeV neutrino energy.

Contribution

It introduces the first calculation of gamma-ray production cross sections using a realistic spectral function model for neutrino-oxygen interactions above 200 MeV.

Findings

At 600 MeV, ~41% of neutral-current interactions emit gamma rays above 6 MeV.

The p_3/2 state dominates the gamma-ray emission contribution.

The model aligns well with electron-nucleus scattering data.

Abstract

It has long been recognized that observation of gamma rays originating from nuclear deexcitation can be exploited to identify neutral-current neutrino-nucleus interactions in water-Cherenkov detectors. We report the results of a calculation of the neutrino- and antineutrino-induced gamma-ray production cross section for oxygen target. Our analysis is focused on the kinematical region of neutrino energy larger than ~200 MeV, in which single-nucleon knockout is known to be the dominant reaction mechanism. The numerical results have been obtained using for the first time a realistic model of the target spectral function, extensively tested against electron-nucleus scattering data. We find that at neutrino energy 600 MeV the fraction of neutral-current interactions leading to emission of gamma-rays of energy larger than 6 MeV is ~41%, and that the contribution of the p_3/2 state is overwhelming.