Search for Charged Higgs Bosons at LEP in General Two Higgs Doublet Models

TL;DR

This paper reports a search for charged Higgs bosons at LEP, setting mass limits and cross-section constraints within Two Higgs Doublet Models, based on data analysis with no significant excess observed.

Contribution

First comprehensive search for charged Higgs bosons at LEP in various decay channels within general Two Higgs Doublet Models, establishing new mass exclusion limits.

Findings

Charged Higgs bosons with mass below 76.7 GeV/c^2 (type I) or 74.4 GeV/c^2 (type II) are excluded.

No significant excess over Standard Model background was observed.

Model independent cross-section limits were derived.

Abstract

A search for pair-produced charged Higgs bosons was performed in the data collected by the DELPHI detector at LEP II at centre-of-mass energies from 189 GeV to 209 GeV. Five different final states, tau+ nu_tau tau- anti-nu_tau, c sbar cbar s, c sbar tau- anti-nu_tau, W* A W* A and W* A tau- anti-nu_tau were considered, accounting for the major expected decays in type I and type II Two Higgs Doublet Models. No significant excess of data compared to the expected Standard Model processes was observed. The existence of a charged Higgs boson with mass lower than 76.7 GeV/c^2 (type I) or 74.4 GeV/c^2 (type II) is excluded at the 95% confidence level, for a wide range of the model parameters. Model independent cross-section limits have also been calculated.