Charged Higgs Boson Effects in the Production and Decay of a Heavy Majorana Neutrino at the LHC

We consider a new interaction between a heavy Majorana neutrino (N) and a charged Higgs boson (H+) and show that it can have drastic implications on lepton number violating (LNV) signal of same-sign dileptons at the LHC. The LNV signal of heavy Majorana neutrinos previously considered at the LHC, pp -> l+ N -> l+ l+ W-, may be overwhelmed by pp -> l+ N -> l+ l+ H-. With the subsequent decays H- -> b t(bar) or H- -> W- H^0, the heavy Majorana neutrino production leads to the spectacular events of l+ l+ b b(bar) + 2 jets. We also explore the case m_N < m_{H+}, where the decay H+ -> l+ N can become the dominant N-production mechanism at the LHC. In particular, we show that the process g b -> t H- followed by t -> b W+ and H- -> l- N -> l- l- W+ could lead to another type of spectacular events of l- l- b + 4 jets.