Search for charged Higgs bosons in $e^{+} e^{-}$ collisions at $\sqrt{s}$ = 181-184 GeV

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