Search for the Standard Model Higgs Boson in OPAL

TL;DR

This paper reports a search for the Standard Model Higgs boson using OPAL data from LEP, observing a slight excess around 95-120 GeV and setting a lower mass limit at 109.7 GeV.

Contribution

First comprehensive search for the Standard Model Higgs boson at LEP with the full dataset, establishing a lower mass bound and analyzing potential signals.

Findings

Observed excess in 95-120 GeV range

Set lower mass limit of 109.7 GeV at 95% CL

Data consistent with background hypothesis

Abstract

A search for the Standard Model Higgs boson with the OPAL detector at LEP was reported. The analysis was based on the full data sample collected at center-of-mass energies of 192-209 GeV in 1999 and 2000, corresponding to an integrated luminosity of approximately 426 /pb. The data shows an excess in a range of 95-120 GeV. The data slightly favour the hypothesis that a signal is present, but also that the data are consistent with the background hypothesis. A lower bound of 109.7 GeV is obtained on the Higgs boson mass at the 95% confidence level.