Framework for maximum likelihood analysis of neutron beta decay observables to resolve the limits of the V-A law

TL;DR

This paper develops a maximum likelihood framework to analyze high-precision neutron beta decay data, aiming to test the V-A law and explore physics beyond the standard model.

Contribution

It introduces a novel statistical method that combines experimental and theoretical uncertainties for analyzing neutron decay observables.

Findings

Future measurements could falsify the V-A law at 10^{-4} precision.

Energy dependence of angular correlations is crucial for testing the standard model.

Precise knowledge of second-class hadronic matrix elements is necessary for accurate tests.

Abstract

We assess the ability of future neutron beta decay measurements of up to O(10^{-4}) precision to falsify the standard model, particularly the V-A law, and to identify the dynamics beyond it. To do this, we employ a maximum likelihood statistical framework which incorporates both experimental and theoretical uncertainties. Using illustrative combined global fits to Monte Carlo pseudodata, we also quantify the importance of experimental measurements of the energy dependence of the angular correlation coefficients as input to such efforts, and we determine the precision to which ill-known "second-class" hadronic matrix elements must be determined in order to exact such tests.