Radiative corrections to the decay \(H^+ \to W^+ A^0\)

Full one-loop electroweak corrections to the on-shell decay \(H^+ \to W^+A^0\) are computed in the framework of models with two Higgs doublets (THDM). Such a decay may be dominant for \(H^{\pm}\) over a wide range of parameter space relevant at present and future colliders. We show that the corrections may approach 40% and in particular are sensitive to \(\lambda_5\), which parameterizes the discrete symmetry breaking term. We suggest that a measurement of the branching ratio of \(H^+ \to W^+A^0\) may offer a possibility of measuring the magnitude of \(\lambda_5\).