Search for sterile neutrinos at reactors with a small core

TL;DR

This paper evaluates the potential of small-core reactors for detecting sterile neutrinos at very short baselines, showing improved sensitivity compared to larger reactors due to reduced core size effects.

Contribution

It demonstrates that small-core reactors significantly enhance sensitivity to sterile neutrino mixing at high mass-squared differences.

Findings

Small reactors improve sensitivity to sterile neutrinos.

Sensitivity can reach as low as 0.03 in sin^2(2θ14).

Large reactors' sensitivity is limited by core size smearing.

Abstract

The sensitivity to the sterile neutrino mixing at very short baseline reactor neutrino experiments is investigated. If the reactor core is relatively large as in the case of commercial reactors, then the sensitivity is lost for $\Delta m^2 \gtrsim$ 1 eV$^2$ due to smearing of the reactor core size. If the reactor core is small as in the case of the experimental fast neutron reactor Joyo, the ILL research reactor or the Osiris reactor, on the other hand, then sensitivity to $\sin^22\theta_{14}$ can be as good as 0.03 for $\Delta m^2 \sim$ several eV$^2$ because of its small size.