Search for light mediators in the low-energy data of the CONNIE reactor neutrino experiment

TL;DR

The paper demonstrates how the CONNIE low-energy neutrino experiment can set new constraints on light mediators beyond the Standard Model, using its data to improve limits on light vector and scalar mediators.

Contribution

First to use CONNIE data to constrain light mediators beyond the Standard Model, providing the best limits among CE$ u$NS experiments for certain mediator masses.

Findings

Set new limits on light vector mediators with mass < 10 MeV.

Set new limits on light scalar mediators with mass < 30 MeV.

Demonstrated CONNIE's potential as a probe for physics beyond the Standard Model.

Abstract

The CONNIE experiment is located at a distance of 30 m from the core of a commercial nuclear reactor, and has collected a 3.7 kg-day exposure using a CCD detector array sensitive to an $\sim$1 keV threshold for the study of coherent neutrino-nucleus elastic scattering. Here we demonstrate the potential of this low-energy neutrino experiment as a probe for physics Beyond the Standard Model, by using the recently published results to constrain two simplified extensions of the Standard Model with light mediators. We compare the new limits with those obtained for the same models using neutrinos from the Spallation Neutron Source. Our new constraints represent the best limits for these simplified models among the experiments searching for CE$\nu$NS for a light vector mediator with mass $M_{Z^{\prime}}<$ 10 MeV, and for a light scalar mediator with mass $M_{\phi}<$ 30 MeV. These results constitute the first use of the CONNIE data as a probe for physics Beyond the Standard Model.