Charged Higgs decays in models with singlet neutrino in large extra   dimensions
  In models with large extra dimensions and TeV scale quantum gravity, small (Dirac) neutrino masses can be obtained naturally if the right-handed neutrino propagates in the extra dimensions. In this scenario, with 2 Higgs doublets, we show that the decay of charged Higgs into {\em left-handed} charged lepton (say \tau) and right-handed neutrino can be significantly enhanced, with O(1) branching ratio, due to the large number of Kaluza-Klein states of the right-handed neutrino. Since \tau's from the standard decay of charged Higgs are {\em right-handed}, the above novel charged Higgs decay can provide a distinctive signature of these models at hadron/lepton colliders. Similarly, top quark decays to b \mu^+ \nu, b \tau^+ \nu through virtual charged Higgs can be enhanced. 
K. Agashe, N.G. Deshpande, G.-H. Wu (ITS, University of Oregon)