Precise Measurements of the Decay of Free Neutrons.

The impact of new and highly precise neutron β decay data is reviewed. We focus on recent results from neutron lifetime, β asymmetry, and electron–neutrino correlation experiments. From these results, weak interaction parameters are extracted with unprecedented precision, which is possible also because of 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. [ABSTRACT FROM AUTHOR]