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

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.

Comments: 8 pages in LaTex, the approach for accounting the neutrino millicharge contribution to the cross section has been corrected. v3: new references including a reference to Review on Particle Physics by Particle Data Group are added, new more stringent limit on millicharge is predicted for the future release of the GEMMA collaboration results