ar X iv : h ep - p h / 03 11 35 0 v 1 2 6 N ov 2 00 3 Radiative corrections to the neutron β − decay within the Standard Model

Radiative corrections to the neutron β−decay within the Standard Model. Abstract Starting with the basic Lagrangian of the Standard Model, the radiative corrections to the neutron β−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 β−decay is parameter-ized by introducing the nucleon electromagnetic form factors and the weak nucleon 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 are 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 excited 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 β−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.