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 neutr ino propagates in the extra dimensions. In this scenario, with 2 Higgs doub lets, we show that the decay of charged Higgs into left-handed charged lept on (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 Higg s are right-handed, the above novel charged Higgs decay can provide a disti nctive 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. (C) 2000 Elsevier Science B.V. All rights reserved.