Radiative Corrections to the Neutron Beta-decay within the Standard Model

Abstract

Starting with the basic Lagrangian of the Standard Model, the radiative corrections to the neutron beta-decay are acquired. The electroweak interactions are consistently taken into consideration amenably to the Weinberg-Salam theory. The effect of the strong quark-quark interactions on the neutron beta-decay is parameterized by introducing the nucleon electromagnetic form factors and the nucleon weak transition current specified by the form factors g_V, g_A, ... The radiative corrections to the total decay probability W and to the asymmetry coefficient of the electron momentum distribution A obtained to constitute δW = 8.7%, δA = -2% . The contribution to the radiative corrections due to allowance for the nucleon form factors and the nucleon exited states amounts up to a few per cent to the whole value of the radiative corrections. The ambiguity in description of the nucleon compositeness is this surely what causes the uncertainties ~0.1% in evaluation of the neutron beta-decay characteristics. For now, this puts bounds to the precision attainable in obtaining the element V_ud of the CKM matrix and the g_V, g_A, ... values from experimental data processing.