Neutrino self-interactions and XENON1T electron recoil excess

TL;DR

This paper proposes a renormalizable model of neutrino self-interactions mediated by a light vector boson, explaining the XENON1T electron recoil excess through solar neutrino interactions and predicting distinctive experimental signatures.

Contribution

It introduces a natural, renormalizable model for neutrino self-interactions that can account for the XENON1T excess and suggests observable signatures for future experiments.

Findings

Coupling values consistent with the XENON1T excess can arise naturally in the model.

The model predicts a characteristic $1/T^2$ energy dependence in neutrino-electron scattering.

Future experiments like ALPS II can probe parts of the model's parameter space.

Abstract

The XENON1T collaboration recently reported an excess in electron recoil events in the energy range between $1-7\,\mathrm{keV}$. This excess could be understood to originate from the known solar neutrino flux, if neutrinos couple to a light vector-mediator with strength $g_{\nu N}$ that kinetically mixes with the photon with strength $\chi$, and $g_{\nu N}\chi\sim10^{-13}$. Here, we show that such coupling values can naturally arise in a renormalizable model of long-range vector-mediated neutrino self-interactions. The model could be discriminated from other explanations of the XENON1T excess by the characteristic $1/T^2$ energy dependence of the neutrino-electron scattering cross section. Other signatures include invisible Higgs and $Z$ decays and lepto-philic charged Higgses at a few $100\,\mathrm{GeV}$. ALPS II will probe part of the viable parameter space.