Final results of the searches for neutral Higgs bosons in e+e- collisions at sqrt(s) up to 209GeV

TL;DR

The ALEPH experiment's final analysis of LEP data up to 209 GeV confirms a significant excess of events consistent with a 115 GeV Standard Model Higgs boson and sets limits on MSSM Higgs parameters.

Contribution

This paper provides the final results of the ALEPH search for the Higgs boson at LEP, including systematic effects and updated limits on Higgs parameters.

Findings

Observation of a 115 GeV Higgs boson candidate

Limits on MSSM Higgs boson masses and parameters

Constraints on invisible Higgs decays

Abstract

The final results of the ALEPH search for the Standard Model Higgs boson at LEP, with data collected in the year 2000 at centre-of-mass energies up to 209 GeV, are presented. The changes with respect to the preceding publication are described and a complete study of systematic effects is reported. The findings of this final analysis confirm the preliminary results published in November 2000 shortly after the closing down of the LEP collider: a significant excess of events is observed, consistent with the production of a $115 \Gcs$ Standard Model Higgs boson. The final results of the searches for the neutral Higgs bosons of the MSSM are also reported, in terms of limits on $\mh$, $\mA$ and $\tanb$. Limits are also set on $\mh$ in the case of invisible decays.