# Searches for sterile neutrinos at very short baseline reactor experiments

## TL;DR

This paper reviews recent experimental efforts, especially six very short baseline reactor experiments, to detect sterile neutrinos, motivated by anomalies in neutrino fluxes and recent potential signals suggesting their existence.

## Contribution

It provides a comprehensive review of current results and future perspectives of very short baseline reactor experiments searching for sterile neutrinos.

## Key findings

- Evidence from LSND, reactor, and calibration experiments suggests sterile neutrinos with ~1 eV² mass splitting.
- Recent signals from MiniBooNE and NEUTRINO-4 hint at possible sterile neutrino oscillations.
- Over 10 experiments are actively searching, with six currently taking data, aiming to confirm or refute sterile neutrino existence.

## Abstract

For a long time there were 3 main experimental indications in favor of the existence of sterile neutrinos: $\bar{\nu_e}$ appearance in the $\bar{\nu_\mu}$ beam in the LSND experiment, $\bar{\nu_e}$ flux deficit in comparison with theoretical expectations in reactor experiments, and $\nu_e$ deficit in calibration runs with radioactive sources in the Ga solar neutrino experiments SAGE and GALEX. All three problems can be explained by the existence of sterile neutrinos with the mass square difference in the ballpark of $1~\mathrm{eV^2}$. Recently the MiniBooNE collaboration observed electron (anti)neutrino appearance in the muon (anti)neutrino beams. The significance of the effect reaches 6.0$\sigma$ level when combined with the LSND result. Even more recently the NEUTRINO-4 collaboration claimed the observation of $\bar{\nu_e}$ oscillations to sterile neutrinos with a significance slightly higher than 3$\sigma$. If these results are confirmed, New Physics beyond the Standard Model would be required. More than 10 experiments are devoted to searches of sterile neutrinos. Six very short baseline reactor experiments are taking data just now. We review the present results and perspectives of these experiments.