Constraining the invisible neutrino decay with KM3NeT-ORCA

TL;DR

This paper investigates how the upcoming KM3NeT-ORCA neutrino detector can significantly improve constraints on invisible neutrino decay models, affecting oscillation parameters and mass ordering determination.

Contribution

It demonstrates that KM3NeT-ORCA can enhance current bounds on neutrino decay by about two orders of magnitude and explores its impact on oscillation parameter measurements.

Findings

KM3NeT-ORCA can improve decay bounds by ~100 times.

Neutrino decay affects measurements of 3 and 31^2.

Decay influences neutrino mass ordering sensitivity.

Abstract

Several theories of particle physics beyond the Standard Model consider that neutrinos can decay. In this work we assume that the standard mechanism of neutrino oscillations is altered by the decay of the heaviest neutrino mass state into a sterile neutrino and, depending on the model, a scalar or a Majoron. We study the sensitivity of the forthcoming KM3NeT-ORCA experiment to this scenario and find that it could improve the current bounds coming from oscillation experiments, where three-neutrino oscillations have been considered, by roughly two orders of magnitude. We also study how the presence of this neutrino decay can affect the determination of the atmospheric oscillation parameters $\sin^2\theta_{23}$ and $\Delta m_{31}^2$, as well as the sensitivity to the neutrino mass ordering.