Search for charged Higgs bosons in e(+)e(-) collisions at energies up to root s=189 GeV

The data collected at centre-of-mass energies of 188.6 GeV by ALEPH at LEP, corresponding to an integrated luminosity of 176.2 pb(-1), are analysed in a search for pair-produced charged Hi,ags bosons H +/-. Three analyses are employed to select the tau(+)7 nu(tau)tau(-)<(nu)over bar>tau, c (s) over bar tau(-)<(nu)over bar>(tau) and c (s) over bar s (c) over bar final states. No evidence for a signal is found. Upper limits are set on the production cross section as a function of the branching fraction B(H+--> tau(+)nu(tau)) and of the mass m(H+/-), assuming that the sum of the branching ratios is equal to one. In the framework of a two-Higgs-doublet model, charged Higgs bosons with masses below 65.4 GeV/c(2) are excluded at 95% confidence level independently of the decay mode. (C) 2000 Published by Elsevier Science B.V. RI ANTONELLI, ANTONELLA/C-6238-2011; Jones, Roger/H-5578-2011; Passalacqua, Luca/F-5127-2011; Murtas, Fabrizio/B-5729-2012; O'Shea, Val/G-1279-2010