Search for the Standard Model Higgs boson at LEP

TL;DR

This paper reports the combined search results for the Standard Model Higgs boson at LEP, indicating a slight excess compatible with a 115.6 GeV/c2 Higgs and setting a lower mass limit of 114.1 GeV/c2.

Contribution

It provides the first combined analysis of all four LEP experiments' data up to 209 GeV, improving the Higgs mass constraints.

Findings

A 2sigma excess at 115.6 GeV/c2 suggests possible Higgs signal.

A 95% CL lower limit of 114.1 GeV/c2 on Higgs mass is established.

Data from ALEPH, DELPHI, L3, and OPAL are combined for the analysis.

Abstract

The combined results of the search for the Standard Model Higgs boson from the four LEP experiments are given. These results are based on the full data sample collected by ALEPH, DELPHI, L3 and OPAL at centre-of-mass energies up to 209GeV, corresponding to a total integrated luminosity of about 2.5fb-1. A slight excess of events over the background expectation is found at the 2sigma level, originating mainly from the ALEPH 4-jet channel. This excess is compatible with what expected for the production of a SM Higgs boson with a mass of 115.6GeV/c2. A combined 95% confidence level lower limit of 114.1GeV/c2 on the mass of the Standard Model Higgs boson is derived.