The eV-Scale Sterile Neutrino and Neutrinoless Double Beta Decay

TL;DR

This paper investigates eV-scale sterile neutrinos' role in neutrinoless double beta decay, constraining their masses using updated experimental data across different mixing schemes and hierarchies, with implications for future experiments.

Contribution

It provides the first comprehensive analysis of sterile neutrino effects on neutrinoless double beta decay across multiple mixing schemes and hierarchies using current global fit data.

Findings

3+1 scheme is most viable among studied models.

Sterile neutrino mass is constrained to about 4.75 eV for NH and 4.72 eV for IH.

Sum of four neutrino masses is limited to approximately 4.8 eV.

Abstract

In short-baseline experiments such as LSND and MiniBooNE, an excess of electron neutrinos has been observed, originating from a muon neutrino beam. To address this anomaly, in the line of many works, we investigate various neutrino mixing schemes involving eV-scale sterile neutrinos alongside three active neutrinos. Using updated experimental and global fit data, we studied neutrinoless double beta decay for three different schemes such as 3+1, 1 + 3, and 2 + 2, which involve one sterile neutrino and three active neutrinos. We have done analysis of these schemes for normal hierarchy (NH) as well as for inverted hierarchy (IH) frameworks, and constrained the sterile neutrino mass in light of current and future neutrinoless double beta decay experiments. The 3+1 scheme is found to be the most viable and at the level of $3\sigma$ the mass of sterile neutrino with respect to the lightest neutrino mass ($m_{\text{lightest}}$) is restricted to $4.75~eV$ for the NH and $4.72~eV$ for the IH. Additionally, the limits on the sum of four neutrino masses are determined to be $4.81~eV$ for the normal hierarchy and $4.78~eV$ for the inverted hierarchy. The updated analysis of all these schemes would help us in understanding physics governing neutrinoless double beta decay and limit on the mass of sterile neutrinos.