Electroweak radiative corrections tot→H+bfor a heavy top quark

The electroweak radiative corrections to $O\left(\frac{\alpha m_t^2}{m_W^2}\right)$ to the tree-level process $t\to H^{+}b$ 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 $tan\beta$ and on the top-quark mass. For some given values of $tan\beta$ and $m_t$, the combined effect of such electroweak corrections and the QCD corrections can result in a ∼ 17% reduction in the width.