Search for charged Higgs bosons in L3

Abstract

A search for pair-produced charged Higgs bosons is performed with the L3 detector at LEP using data collected at centre-of-mass energies between 200 and 209 GeV, corresponding to an integrated luminosity of 217.8 pb^-1. We observe an excess of events in the H+-H -> cscs and cs\tau\nu channels in the mass region around 68 GeV, which is most significant at low values of the H+ -> \tau\nu branching ratio. Including data taken at lower centre-of-mass energies, the excess is compatible with a 4.4\sigma fluctuation in the background. Interpreting this excess as a statistical fluctuation in the background, lower limits on the charged Higgs mass are derived at the 95% confidence level. They vary from 67.1 to 84.9 GeV as a function of the H+ -> \tau\nu branching ratio. These results are PRELIMINARY.