Novel constraints on neutrino physics beyond the standard model from the CONUS experiment

TL;DR

This paper uses data from the CONUS experiment to set new constraints on various beyond the standard model neutrino interactions and mediators, leveraging low-background measurements of CEνNS and neutrino-electron scattering.

Contribution

It provides the world's best limits on tensor NSIs and new constraints on scalar and vector mediators from reactor neutrino data, advancing the search for new physics beyond the standard model.

Findings

Set world's best limits on tensor NSIs from CEνNS.

Constrained scalar and vector mediators with coupling constants as low as 5×10⁻⁵.

Achieved stronger bounds on mediator masses below 1 MeV and 10 MeV from neutrino-electron scattering.

Abstract

The measurements of coherent elastic neutrino-nucleus scattering (CE$\nu$NS) experiments have opened up the possibility to constrain neutrino physics beyond the standard model of elementary particle physics. Furthermore, by considering neutrino-electron scattering in the keV-energy region, it is possible to set additional limits on new physics processes. Here, we present constraints that are derived from CONUS germanium data on beyond the standard model (BSM) processes like tensor and vector non-standard interactions (NSIs) in the neutrino-quark sector, as well as light vector and scalar mediators. Thanks to the realized low background levels in the CONUS experiment at ionization energies below 1 keV, we are able to set the world's best limits on tensor NSIs from CE$\nu$NS and constrain the scale of corresponding new physics to lie above 360 GeV. For vector NSIs, the derived limits strongly depend on the assumed ionization quenching factor within the detector material, since small quenching factors largely suppress potential signals for both, the expected standard model CE$\nu$NS process and the vector NSIs. Furthermore, competitive limits on scalar and vector mediators are obtained from the CE$\nu$NS channel at reactor-site which allow to probe coupling constants as low as $5\cdot10^{-5}$ of low mediator masses, assuming the currently favored quenching factor regime. The consideration of neutrino-electron scatterings allows to set even stronger constraints for mediator masses below $\sim1$ MeV and $\sim 10$ MeV for scalar and vector mediators, respectively.