Neutrino nonstandard interactions in the supernova

TL;DR

This paper explores how nonstandard neutrino interactions affect neutrino and antineutrino appearance probabilities in supernovae, revealing potential observable effects at low energies that could indicate new physics beyond the Standard Model.

Contribution

The study extends previous solar neutrino NSI frameworks to supernovae, analyzing energy-dependent appearance probabilities and identifying potential low-energy signatures of NSI in supernova neutrinos.

Findings

Increased electron neutrino and antineutrino probabilities at low energy for normal hierarchy with NSI.

Probabilities for inverse hierarchy remain unchanged by NSI across all energies.

Neutrino decay into antineutrino and majoron remains too small to detect, even with NSI.

Abstract

Neutrino nonstandard interactions (NSI) were investigated earlier in the solar case and were shown to reduce the tensions between the data and the large mixing angle solution predictions. We extend the previous framework to the supernova and evaluate the appearance probabilities for neutrinos and antineutrinos as a function of their energy after leaving the collapsing star with and without NSI. For normal hierarchy the probability for electron neutrinos and antineutrinos at low energy ($E\lesssim 0.8-0.9 MeV$) is substantially increased with respect to the non-NSI case and joins its value for inverse hierarchy which is constant with energy. Also for inverse hierarchy the NSI and non-NSI probabilities are the same for each neutrino and antineutrino species. Although detection in such a low energy range remains at present an experimental challenge, it will become a visible trace of NSI with normal hierarchy if they exist. On the other hand the neutrino decay probability into an antineutrino and a majoron, an effect previously shown to be induced by dense matter, is, as in the case of the sun, too small to be observed as a direct consequence of NSI.