QCD Corrections to the Charged-Higgs-Boson Decay of a Heavy Top Quark

Abstract

It is shown that up to an over all scale the lowest-order QCD corrections to $t\to H^{+}b$ and to $t\to W^{+}b$ are the same in the heavy top limit. Asymptotically, they are given by $-\frac{4{\alpha }_s}{3\pi }[\frac{{\pi }^2}{3}-\frac{5}{4}]$, resulting in a reduction in the decay rate by about $9\%$, rather than $6\%$ reported previously in the literature. This is verified explicitly by an analytic calculation. The application of the equivalence theorem to this process is also discussed.

Comments: 12 pages, UPR-0508T, UM-TH-92-13