Dispersion relation analysis of the radiative corrections to gA in the neutron β-decay

We present the first and complete dispersion relation analysis of the inner radiative corrections to the axial coupling constant g(A) in the neutron beta-decay. Using experimental inputs from the elastic form factors and the spin-dependent structure function g(1), we determine the contribution from the gamma W-box diagram to a precision better than 10(-4). Our calculation indicates that the inner radiative corrections to the Fermi and the Gamow-Teller matrix element in the neutron beta-decay are almost identical, i.e. the ratio lambda = g(A)/g(V) is almost unrenormalized. With this result, we predict the bare axial coupling constant to be g(A) = -1.2754(13)(exp)(2)(RC) based on the PDG average lambda = -1.2756(13).

Automated summary

In this study, we conducted the first complete dispersion relation analysis of the inner radiative corrections to the axial coupling constant g(A) in neutron beta-decay. By using experimental inputs, we determined the contribution from the gamma W-box diagram with a high precision. Our calculation showed that the inner radiative corrections to the Fermi and the Gamow-Teller matrix element in neutron beta-decay are nearly identical, and the ratio of the axial coupling constant remains almost unrenormalized.