Solar Neutrinos and the Strongest Oscillation Constraints on Scalar NSI

TL;DR

This paper investigates scalar non-standard neutrino interactions (sNSI), deriving new constraints from solar and reactor data, showing solar neutrinos provide significantly stronger limits on sNSI than terrestrial experiments.

Contribution

It provides the first comprehensive constraints on all sNSI parameters using combined solar and reactor neutrino data, highlighting the enhanced sensitivity of solar neutrinos.

Findings

Solar neutrinos are over an order of magnitude more sensitive to sNSI than terrestrial experiments.

Constraints on all sNSI parameters are derived for the first time from combined data.

The absolute neutrino mass scale is also constrained through this analysis.

Abstract

Scalar non-standard neutrino interactions (sNSI) is a scenario where neutrinos can develop a medium dependent contribution to their mass due to a new scalar mediator. This scenario differs from the commonly discussed vector mediator case in that the oscillation effect scales with density rather than density and neutrino energy. Thus the strongest oscillation constraint comes from solar neutrinos which experience the largest density in a neutrino oscillation experiment. We derive constraints on all the sNSI parameters as well as the absolute neutrino mass scale by combining solar and reactor data and find solar neutrinos to be $>1$ order of magnitude more sensitive to sNSI than terrestrial probes such as long-baseline experiments.