RADIATIVE-CORRECTIONS AND SEMILEPTONIC B-DECAYS

A prescription for approximating electroweak radiative corrections to weak decays is given. The method is illustrated for 'e» and a simplified (structureless) model of B'Me», M=D or , where the complete O() corrections are known. Our procedure is shown to provide a proper description of radiation damping near the electrons end-point energy and a reasonable estimate of radiative corrections for much of the spectrum as well as the integrated rate. As a practical application, it is applied to the semileptonic decays B'Xe» where an exact O() treatment of radiative corrections is very difficult, but an estimate of their effect is important for the extraction of Vub and leptonic branching ratios. We also discuss an 18% enhancement of (4S)'B+B- relative to B0B» 0 due to large Coulomb corrections near threshold. © 1990 The American Physical Society.