Search for charged Higgs bosons in e+e- collisions at sqrt(s) = 181-184 GeV

Abstract

Data collected at centre-of-mass energies of 181-184 GeV by ALEPH at LEP corresponding to an integrated luminosity of 56.9 pb-1, are analysed in a search for pair-produced charged Higgs bosons H+-. Three analyses are employed to select the tau^+ nu_tau tau^- nubar_tau, c sbar tau^- nubar_tau/ cbar s tau^+ nu_tau and c sbar s cbar final states. No evidence for a signal is found. Mass limits are set as a function of the branching fraction B(H+ -> tau^+ nu_tau). Under the assumption that the decay modes considered cover the totality of the possible final states, charged Higgs bosons with masses below 59 GeV/c^2 are excluded at 95% C.L. independently of B(H+ -> tau^+ nu_tau).