Enhanced active-sterile neutrino polarizability at the intensity frontier

TL;DR

This paper investigates active-sterile neutrino polarizability, deriving new experimental constraints, proposing a light mediator model that explains the MiniBooNE excess, and discussing broader theoretical implications.

Contribution

It introduces a novel active-sterile neutrino polarizability model, derives experimental constraints, and shows its potential to explain the MiniBooNE anomaly.

Findings

New constraints on active-sterile neutrino polarizability from neutrino scattering experiments.

A light mediator model can account for the MiniBooNE low-energy excess.

Discussion of alternative realizations of the higher-dimensional operator.

Abstract

Electromagnetic probes of neutrinos can provide insights into physics beyond the Standard Model. Among the possible electromagnetic interactions of neutrinos is neutrino polarizability, a dimension-7 effective operator that couples two neutrinos to two photons. In this manuscript, we study a realization of the neutrino polarizability operator in which one of the active neutrinos is replaced by a sterile neutrino. We derive new constraints on this active-sterile neutrino polarizability from its contribution to neutrino-nucleus scattering with a single photon in the final state at neutrino experiments. We show that a realization of this operator via a light mediator can explain the MiniBooNE low-energy excess while remaining consistent with other experimental constraints. Finally, we comment on additional model realizations of this higher-dimensional operator.