Four Generations in Phenomenology

In four–generation models Higgs masses of 115–315 GeV are perfectly allowed by electroweak precision data. In this mass range we find dramatic effects on Higgs phenomenology at hadron colliders: production rates are enhanced, weak–boson–fusion channels are suppressed, angular distributions are modified, Higgs pairs can be observed, and Higgs decays to Majorana neutrinos can lead to exotic signals.