Hello! I haven't really seen a feynman diagram with a higgs boson decaying to a top-anti top quark pair. The mass of a top pair is much higher than the Higgs mass on shell, but is there any reason why we can't have a Higgs boson (very) off-shell decay to 2 top quarks. The probability of that happening must be quite low, but is there any reason to not happen at all? Thank you!