Symmetry violations in nuclear and neutron $\beta$ decay

TL;DR

This paper reviews how nuclear and neutron beta decay experiments can probe physics beyond the Standard Model, including symmetry violations, and discusses current constraints, novel tests, and future experimental directions.

Contribution

It provides a comprehensive overview of symmetry violations in beta decay, highlighting new methods to test Lorentz invariance and compare constraints from various experiments.

Findings

Limits on time-reversal symmetry violation in beta decay.

Sensitivity of beta decay to Lorentz symmetry breaking.

Roadmap for future beta decay experiments.

Abstract

The role of $\beta$ decay as a low-energy probe of physics beyond the Standard Model is reviewed. Traditional searches for deviations from the Standard Model structure of the weak interaction in $\beta$ decay are discussed in the light of constraints from the LHC and the neutrino mass. Limits on the violation of time-reversal symmetry in $\beta$ decay are compared to the strong constraints from electric dipole moments. Novel searches for Lorentz symmetry breaking in the weak interaction in $\beta$ decay are also included, where we discuss the unique sensitivity of $\beta$ decay to test Lorentz invariance. We end with a roadmap for future $\beta$-decay experiments.