Radiative corrections in Ke4 decay

The final state interaction of pions in the decay K±→π+π-e±ν allows one to obtain the value of the isospin and angular momentum zero pion-pion scattering length a00. To extract this quantity from experimental data the radiative corrections (RC) have to be taken into account. Based on the lowest order results and the factorization hypothesis, we get the expressions for RC in the leading and next-to leading logarithmical approximation. It is shown that the decay width dependence on the lepton mass me through the parameter σ=(α)/(2π)(ln(M2)/(me2)-1) has the standard form of the Drell-Yan process and is proportional to the Sommerfeld-Sakharov factor. The numerical estimations are presented. (orig.)