New bounds on neutrino electric millicharge from limits on neutrino magnetic moment

TL;DR

This paper derives new, more stringent bounds on the neutrino electric millicharge using recent experimental limits on neutrino magnetic moments, and predicts further improvements with ongoing experiments.

Contribution

It provides the first direct upper bound on neutrino millicharge from GEMMA experiment data and forecasts future tighter constraints with ongoing experimental phases.

Findings

New upper bound on neutrino millicharge: < 1.5 x 10^{-12} e_0

Projected bounds with future data: < 3.7 x 10^{-13} e_0 and < 1.8 x 10^{-13} e_0

Improved constraints surpass previous limits from TEXONO experiment.

Abstract

Using the new limit on the neutrino anomalous magnetic moment recently obtained by the GEMMA experiment on measurements of the cross section for the reactor antineutrino scattering on free electrons, we get a new direct upper bound on the neutrino millicharge $\mid q_{\nu} \mid < 1.5 \times 10^{-12} e_0$. This is a factor of 2 more stringent constraint than the previous bound obtained from the TEXONO reactor experiment data that is included to the Review of Particle Properties 2012. We predict that with data from the ongoing new phase of the GEMMA experiment the upper bound on the neutrino millicharge will be reduced to $\mid q_{\nu} \mid < 3.7 \times 10^{-13}e_0$ within two years. We also predict that with the next phase of the considered experiment the upper bound on the millicharge will be reduced by an order of magnitude over the present bound and reach the level $\mid q_{\nu} \mid < 1.8 \times 10^{-13}e_0$ within approximately four years.