Measurement of the Axial-Vector Coupling Constant $g_A$ in Neutron Beta Decay

Abstract

The matrix element \Vud of the CKM matrix can be determined by two independent measurements in neutron decay: the neutron lifetime ${\tau }_n$ and the ratio of coupling constants $\lambda =g_A/g_V$, which is most precisely determined by measurements of the beta asymmetry angular correlation coefficient~$A$. We present recent progress on the determination of these coupling constants.

Comments: Proceedings of the 8th International Workshop on the CKM Unitarity Triangle (CKM 2014), Vienna, Austria, September 8-12, 2014