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

TL;DR

This study searches for charged Higgs bosons in electron-positron collisions at energies of 181-184 GeV using ALEPH data, setting mass limits and excluding certain mass ranges based on the absence of signals.

Contribution

It provides new mass exclusion limits for charged Higgs bosons at LEP energies, considering various decay channels and assuming comprehensive coverage of possible final states.

Findings

No evidence for charged Higgs bosons was observed.

Charged Higgs bosons with masses below 59 GeV/c^2 are excluded at 95% confidence level.

Mass limits are set independently of the decay branching fraction.

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).