Searches for Exotic Higgs Bosons at LEP

TL;DR

This paper reviews searches for exotic Higgs bosons, especially in Two Higgs Doublet Models, at LEP, setting limits on their existence based on data up to 209 GeV.

Contribution

It summarizes experimental searches for non-Standard Model Higgs bosons at LEP, focusing on models with additional Higgs doublets and their experimental constraints.

Findings

No evidence for exotic Higgs bosons was found.

Limits were set on the masses and couplings of Higgs bosons in 2HDM.

Data up to 209 GeV was used for the analysis.

Abstract

In the Standard Model (SM), the weak gauge bosons and fermions acquire mass through the Higgs mechanism. A lower limit on the SM Higgs mass of 114.4 GeV was obtained from the direct search at LEP. Although a single Higgs doublet is sufficient to explain the non-zero particle masses while keeping the theory SU(2) gauge invariant, several extensions to this minimal model were proposed, to which this limit does not apply. Most of the models discussed here introduce one additional Higgs doublet and are therefore called Two Higgs doublet models (2HDM). Several signatures predicted by such models have been searched for at LEP using data collected at center-of-mass energies up to 209 GeV. All limits quoted in this report are at 95% confidence level.