Probing Light Mediators in the Radiative Emission of Neutrino Pair

TL;DR

This paper explores using coherently enhanced neutrino pair emission to detect light mediators between electrons and neutrinos, achieving sensitivity surpassing current constraints for mediator masses from 10^{-3} to 10^4 eV.

Contribution

It introduces a novel method leveraging atomic-scale momentum transfer to probe light-mediator interactions with unprecedented sensitivity.

Findings

Sensitivity to scalar mediators down to |y^e y^ν| < 10^{-19}

Sensitivity to vector mediators down to |g^e g^ν| < 10^{-26}

Order of magnitude improvements over existing constraints

Abstract

We propose a new possibility of using the coherently enhanced neutrino pair emission to probe light-mediator interactions between electron and neutrinos. With typical momentum transfer at the atomic $\mathcal O(1$\,eV) scale, this process is extremely sensitive for the mediator mass range $\mathcal O(10^{-3} \sim 10^4$) eV. The sensitivity on the product of couplings with electron ($g^e$ or $y^e$) and neutrinos ($g^\nu$ or $y^\nu$) can touch down to $|y^e y^\nu| < 10^{-9} \sim 10^{-19}$ for a scalar mediator and $|g^e g^\nu| < 10^{-15} \sim 10^{-26}$ for a vector one, with orders of improvement from the existing constraints.