Distinctive Heavy Higgs Decays
  For a heavy Higgs boson above the $t\bar t$ threshold we consider three decay modes that could compete with decay to $t\bar t$, even in the alignment limit of a 2-Higgs doublet model. The decays $H\to AZ$, $ Z'Z'$ and $\tau'\tau'$ show that heavy Higgs decays can be an effective probe of new physics both within and beyond this model. 
B. Holdom and M. Ratzlaff
hep-ph hep-ex