Search for charged Higgs bosons in e+e- collisions at energies up to sqrt(s) = 209GeV

TL;DR

This paper reports a search for charged Higgs bosons in electron-positron collisions at energies up to 209 GeV, finding no evidence and setting mass exclusion limits within a two-Higgs-doublet model.

Contribution

First search for charged Higgs bosons at LEP energies with new mass limits established in a two-Higgs-doublet framework.

Findings

No signal observed for charged Higgs bosons.

Charged Higgs bosons with masses below 79.3 GeV/c2 are excluded at 95% confidence.

Limits are set independently of the branching ratios.

Abstract

A search for charged Higgs bosons produced in pairs is performed with data collected at centre-of-mass energies ranging from 189 to 209 GeV by ALEPH at LEP, corresponding to a total luminosity of 629 invpb. The three final states taunutaunu, taunucs and cscs are considered. No evidence for a signal is found and lower limits are set on the mass M_H+ as a function of the branching fraction B(H to taunu). In the framework of a two-Higgs-doublet model, and assuming B(H+ to taunu + B(H+ to cs) = 1 charged Higgs bosons with masses below 79.3 Gev/c2 are excluded at 95% confidence level independently of the branching ratios.