Radiative corrections to the Higgs-boson decay rateΓ(H→ZZ)in the minimal supersymmetric model

We consider radiative corrections to the decay rate $\Gamma (H\to ZZ)$ of the heavy $\mathrm{CP}$-even Higgs boson of the minimal supersymmetric model to two $Z$ bosons. We perform a one-loop Feynman diagram calculation in the on-mass-shell renormalization scheme, and include the third generation of quarks and squarks. The tree-level rate is suppressed by a mixing angle factor and decreases as $\frac{1}{M_H}$ for large $M_H$. The corrected rate overcomes this suppression and increases with $M_H$ for $M_H$ sufficiently large. The corrections can be very large and depend in detail on the top-squark masses and $A$ term, as well as the supersymmetric Higgs-boson mass parameter $\mu$.