General one-loop formulas for decay \(h\rightarrow Z\gamma\)

One-loop contributions to the \(h\rightarrow Z\gamma\) are evaluated in the one-loop approximation. The unitary gauge gauge is used. The analytic result is expressed in terms of the Passarino-Veltman functions. The calculations are applicable as for the Standard Model as well for a wide class of its gauge extensions. In particular, the decay width of a charged Higgs boson \(H^{\pm}\rightarrow W^{\pm}\gamma\) can be derived. The consistence of our formulas and several specific earlier results is shown.