ELECTROWEAK RADIATIVE-CORRECTIONS TO T-]H+B FOR A HEAVY TOP QUARK

The electroweak radiative corrections to O(alpham(t)2/m(W)2) to the tree-level process t --> H+b are calculated for a heavy top quark. The corrections imply a few to 10% reduction in the partial width relative to the tree-level result, depending strongly on the parameter tanbeta and on the top-quark mass. For some given values of tanbeta and m(t), the combined effect of such electroweak corrections and the QCD corrections can result in a approximately 17% reduction in the width.