Physics Beyond Standard Model in Neutron Beta Decay

TL;DR

This paper investigates constraints on new physics beyond the Standard Model using neutron beta decay data, employing a general effective Hamiltonian with vector, scalar, and tensor interactions, and highlights the sensitivity of results to nucleon form factors.

Contribution

It introduces a comprehensive analysis of neutron beta decay limits on beyond Standard Model physics using a general Lorentz-invariant effective Hamiltonian.

Findings

Limits set on new physics parameters from neutron decay data

Dependence of results on g_A/g_V ratio of nucleon form factors

Two-parameter fits reveal significant parameter sensitivities

Abstract

Limits from neutron beta decay on parameters describing physics beyond the Standard Model are presented. New Physics is described by the most general Lorentz invariant effective Hamiltonian involving vector, scalar and tensor operators and Standard Model fields only. Two-parameter fits to the decay parameters measured in free neutron beta decay have been done, in some cases indicating rather big dependence of the results on g_A/g_V ratio of nucleon form factors at zero four-momentum transfer.