Signatures of MSSM charged Higgs bosons via chargino-neutralino decay channels at the LHC

We assess the potential of detecting a charged Higgs boson of the MSSM at the LHC via its decays into a chargino and a neutralino. We focus our attention on the region of parameter space with m(H)+/- > m(t) and 3 less than or similar to tan beta less than or similar to 10, where identification of the H+/- via other decay modes has proven to be ineffective. Searching for means to plug this hole, we simulate the decays H +/- --> <(<chi>)over tilde>(+/-)(1)<(<chi>)over tilde>(0)(1) and H+/- --> <(<chi>)over tilde>(+/-)(1)<(<chi>)over tilde>(0)(2), <(<chi>)over tilde>(+/-)(1)<(<chi>)over tilde>(0)(3) - the former can yield a single hard lepton (from the chargino decay) while the latter can yield three leptons (from the chargino and neutralino decays). Coupled with the dominant top quark + charged Higgs boson production mode, the resulting signature is one or three hard, isolated leptons, substantial missing transverse momentum and a reconstructed (via st 3-jet invariant mass) top quark. The single lepton channel is swamped by background processes; however, with suitable cuts, a trilepton signal emerges. While such a signal suffers from a low number of surviving events (after cuts) and is dependent on several MSSM input parameters (notably M-2, mu, and slepton masses), it does fill at least some of the void left by previous investigations.