5 Reasons to expect an 8 MeV line in the SN 1987A neutrino spectrum

TL;DR

This paper discusses the potential existence of an 8 MeV neutrino line in SN 1987A's spectrum, providing reasons for its expectation and linking it to ongoing neutrino mass experiments like KATRIN.

Contribution

It offers five theoretical reasons to expect an 8 MeV neutrino line and connects this to experimental efforts in neutrino mass measurement.

Findings

Previous evidence for the line is questionable due to background overlap.

Five reasons are provided to support the existence of the 8 MeV neutrino line.

The KATRIN experiment could offer additional validation for the line and the neutrino mass model.

Abstract

Evidence was previously reported for an 8 MeV neutrino line associated with SN 1987A based on an analysis of 997 events recorded in the Kamiokande-II detector on the day of the supernova. That claimed line, however, occurred at the peak of the background spectrum, and both had a similar shape, making the claim tenuous at best. Here the claim is buttressed by providing five reasons to expect such an 8 MeV neutrino line. A final section of the paper concerns the ongoing KATRIN experiment to find the neutrino mass, which might provide additional support for the line, should it validate a controversial 3 + 3 model of the neutrino masses, including a tachyonic (m2 < 0) mass.