Precise Measurements of the Decay of Free Neutrons

TL;DR

This paper reviews recent high-precision measurements of free neutron decay, highlighting their impact on understanding weak interactions and constraining new physics beyond the Standard Model.

Contribution

It provides a comprehensive analysis of recent neutron decay data and demonstrates how these measurements refine weak interaction parameters and limit new physics.

Findings

Neutron lifetime and asymmetry measurements have achieved unprecedented precision.

Neutron decay data impose tighter constraints on new physics than high-energy experiments.

Progress in effective field theory and lattice QCD enhances interpretation of decay results.

Abstract

The impact of new and highly precise neutron \b{eta} decay data is reviewed. We focus on recent results from neutron lifetime, \b{eta} asymmetry, and electron-neutrino correlation experiments. From these results, weak interaction parameters are extracted with unprecedented precision, possible also due to progress in effective field theory and lattice QCD. Limits on New Physics beyond the Standard Model derived from neutron decay data are sharper than those derived from high-energy experiments, except for processes involving right-handed neutrinos.