The Standard Model Theory of Neutron Beta Decay

We review the status of the Standard Model theory of neutron beta decay. Particular emphasis is put on the recent developments in the electroweak radiative corrections. Given that some existing approaches give slightly different results, we thoroughly review the origin of discrepancies, and provide our recommended value for the radiative correction to the neutron and nuclear decay rates. The use of dispersion relation, lattice Quantum Chromodynamics, and an effective field theory framework allows for high-precision theory calculations at the level of 10-4, turning neutron beta decay into a powerful tool to search for new physics, complementary to high-energy collider experiments. We offer an outlook to the future improvements.

Automated summary

This article reviews the current status of the Standard Model theory of neutron beta decay, with particular emphasis on recent developments in electroweak radiative corrections. The discrepancies in existing approaches are thoroughly reviewed to provide a recommended value for the neutron and nuclear decay rate's radiative correction. Through the use of dispersion relation, lattice Quantum Chromodynamics, and an effective field theory framework, high-precision theory calculations at the level of 10-4 are achieved, making neutron beta decay a powerful tool for searching for new physics, complementary to high-energy collider experiments. Future improvements are also discussed.