Testing secret interaction with astrophysical neutrino point sources

TL;DR

This paper uses astrophysical neutrino observations from NGC 1068 and TXS 0506+056 to constrain hypothetical secret neutrino interactions, highlighting the importance of neutrino mass assumptions.

Contribution

It introduces a novel method to test secret neutrino interactions using astrophysical neutrino point sources and discusses the impact of neutrino mass uncertainties on these limits.

Findings

Limits on secret neutrino interactions derived from astrophysical observations.

Neutrino mass assumptions significantly affect the strength of the constraints.

Astrophysical neutrino data can serve as a probe for new physics in the neutrino sector.

Abstract

Recently, the IceCube collaboration observed a neutrino excess in the direction of NGC 1068 with high statistical significance. This constitutes the second detection of an astrophysical neutrino point source after the discovery of a variable emission originating from the blazar TXS~0506+056. Neutrinos emitted by these sources traverse huge, well-determined distances on their way to Earth. This makes them a promising tool to test new physics in the neutrino sector. We consider secret interactions with the cosmic neutrino background and discuss their impact on the flux of neutrino point sources. The observation of emission from NGC 1068 and TXS 0506+056 can then be used to put limits on the strength of the interaction. We find that our ignorance of the absolute neutrino masses has a strong impact and, therefore, we present limits in two benchmark scenarios with the sum of the neutrino masses around their lower and upper limits.