# Reactor neutrino oscillations as constraints on Effective Field Theory

## TL;DR

This paper investigates how short-baseline reactor neutrino experiments can constrain the Standard Model Effective Field Theory, especially focusing on tensor and scalar operators, and finds they provide unique sensitivity to certain off-diagonal flavor interactions.

## Contribution

It provides the first leading-order analysis of SMEFT effects on reactor neutrino oscillations, highlighting the potential to probe tensor and scalar operators.

## Key findings

- Reactor experiments cannot probe charged-current contact interactions of vector or pseudo-scalar type at leading order.
- Flavor-diagonal vector coefficients do not affect oscillation probabilities.
- Constraints on tensor and scalar SMEFT operators are derived from Daya Bay and RENO data.

## Abstract

We study constraints on the Standard Model Effective Field Theory (SMEFT) from neutrino oscillations in short-baseline reactor experiments. We calculate the survival probability of reactors antineutrinos at the leading order in the SMEFT expansion, that is including linear effects of dimension-6 operators. It is shown that, at this order, reactor experiments alone cannot probe charged-current contact interactions between leptons and quarks that are of the (pseudo)vector (V$\pm$A) or pseudo-scalar type. We also note that flavor-diagonal (pseudo)vector coefficients do not have observable effects in oscillation experiments. In this we reach novel or different conclusions than prior analyses of non-standard neutrino interactions. On the other hand, reactor experiments offer a unique opportunity to probe tensor and scalar SMEFT operators that are off-diagonal in the lepton-flavor space. We derive constraints on the corresponding SMEFT parameters using the most recent data from the Daya Bay and RENO experiments.