Search for the Standard Model Higgs Boson at LEP

TL;DR

This paper reports a combined analysis of LEP data searching for the Standard Model Higgs boson, establishing a lower mass limit of 114.4 GeV/c2 at 95% confidence and setting bounds on its coupling to Z bosons.

Contribution

It provides the first combined LEP analysis setting a lower mass limit and coupling bounds for the Standard Model Higgs boson using extensive e+e- collision data.

Findings

Lower bound of 114.4 GeV/c2 on Higgs mass at 95% confidence

Combined data from four collaborations enhances search sensitivity

Upper bounds on HZZ coupling under various decay assumptions

Abstract

The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have collected a total of 2461 pb-1 of e+e- collision data at centre-of-mass energies between 189 and 209 GeV. The data are used to search for the Standard Model Higgs boson. The search results of the four collaborations are combined and examined in a likelihood test for their consistency with two hypotheses: the background hypothesis and the signal plus background hypothesis. The corresponding confidences have been computed as functions of the hypothetical Higgs boson mass. A lower bound of 114.4 GeV/c2 is established, at the 95% confidence level, on the mass of the Standard Model Higgs boson. The LEP data are also used to set upper bounds on the HZZ coupling for various assumptions concerning the decay of the Higgs boson.