KATRIN Sensitivity to Sterile Neutrino Mass in the Shadow of Lightest Neutrino Mass

TL;DR

This paper evaluates KATRIN's ability to detect sterile neutrinos by analyzing how their presence affects the Tritium beta-electron spectrum, considering the impact of active neutrino mass uncertainties.

Contribution

It provides a comprehensive analysis of KATRIN's sensitivity to sterile neutrino parameters across the full allowed mass and mixing range, including the influence of active neutrino mass scale.

Findings

KATRIN can detect mixing angles as small as sin^2(2θ_s) ~ 10^-2 after 3 years.

For small mixing angles, KATRIN sets strong limits on active-sterile mass-squared differences.

The sensitivity depends on the unknown active neutrino mass scale.

Abstract

The presence of light sterile neutrinos would strongly modify the energy spectrum of the Tritium \beta-electrons. We perform an analysis of the KATRIN experiment's sensitivity by scanning almost all the allowed region of neutrino mass-squared difference and mixing angles of the 3+1 scenario. We consider the effect of the unknown absolute mass scale of active neutrinos on the sensitivity of KATRIN to the sterile neutrino mass. We show that after 3 years of data-taking, the KATRIN experiment can be sensitive to mixing angles as small as sin^2 (2\theta_s) ~ 10^-2. Particularly we show that for small mixing angles, sin^2 (2\theta_s) < 0.1, the KATRIN experiment can gives the strongest limit on active-sterile mass-squared difference.