BEST sensitivity to O(1) eV sterile neutrino

TL;DR

This paper evaluates the sensitivity of the upcoming BEST experiment to detect or exclude ~1 eV sterile neutrinos, analyzing its potential impact on existing Gallium anomaly interpretations.

Contribution

It provides a detailed sensitivity analysis of BEST and combines results from Gallium experiments to refine sterile neutrino parameter space constraints.

Findings

BEST can exclude certain sterile neutrino parameters if no signal is observed.

If BEST detects a signal, it will significantly improve parameter estimates.

Combined Gallium data narrows the sterile neutrino model space.

Abstract

Numerous anomalous results in neutrino oscillation experiments can be attributed to interference of ~1 eV sterile neutrino. The specially designed to fully explore the Gallium anomaly Baksan Experiment on Sterile Transitions (BEST) starts next year. We investigate the sensitivity of BEST in searches for sterile neutrino mixed with electron neutrino. Then, performing the combined analysis of all the Gallium experiments (SAGE, GALLEX, BEST) we find the regions in model parameter space (sterile neutrino mass and mixing angle), which will be excluded if BEST agrees with no sterile neutrino hypothesis. For the opposite case, if BEST observes the signal as it follows from the sterile neutrino explanation of the Gallium (SAGE and GALLEX) anomaly, we show how BEST will improve upon the present estimates of the model parameters.