Searches for Charged Higgs Bosons at LEP

TL;DR

The LEP experiments searched for charged Higgs bosons, finding a 4.4 sigma excess in one experiment at 68 GeV, but no confirmation from others, leading to a lower mass limit of 78.5 GeV.

Contribution

First combined LEP search for charged Higgs bosons with updated data, setting new lower mass limits despite a localized excess.

Findings

A 4.4 sigma excess at 68 GeV in L3 data

No consistent excess observed by other LEP experiments

Charged Higgs mass lower limit set at 78.5 GeV

Abstract

The four LEP experiments Aleph, Delphi, L3 and Opal updated their searches for pair production of charged Higgs bosons using more than 210/pb luminosity collected per experiment in the year 2000. Combining it with previously collected data, a significant deviation from background (equivalent to 4.4 sigma) is found by the L3 collaboration for low values of the branching ratio H+/- -> tau nu around masses of about 68 GeV. This excess is however not seen by the other LEP collaborations and thus a lower limit on the charged Higgs mass is set at 78.5 GeV at 95% confidence level. All results reported here are still preliminary.