Search for the standard model Higgs boson in the decay channel H to ZZ to 4 leptons in pp collisions at sqrt(s) = 7 TeV

TL;DR

This paper reports a search for the Higgs boson in the four-lepton decay channel using 7 TeV proton-proton collision data, setting exclusion limits and observing small excesses near certain masses.

Contribution

First search for the Higgs boson in the H to ZZ to 4 leptons channel at 7 TeV with detailed background analysis and exclusion limits.

Findings

Observed events are consistent with background expectations.

Excluded Higgs mass ranges at 95% confidence level.

Small excesses observed around 119, 126, and 320 GeV.

Abstract

A search for a Higgs boson in the four-lepton decay channel H to ZZ, with each Z boson decaying to an electron or muon pair, is reported. The search covers Higgs boson mass hypotheses in the range 110 < mH < 600 GeV. The analysis uses data corresponding to an integrated luminosity of 4.7 inverse femtobarns recorded by the CMS detector in pp collisions at sqrt(s) = 7 TeV from the LHC. Seventy-two events are observed with four-lepton invariant mass m[4 leptons] > 100 GeV (with thirteen below 160 GeV), while 67.1 +/- 6.0 (9.5 +/-1.3) events are expected from background. The four-lepton mass distribution is consistent with the expectation of standard model background production of ZZ pairs. Upper limits at 95% confidence level exclude the standard model Higgs boson in the ranges 134-158 GeV, 180-305 GeV, and 340 -465 GeV. Small excesses of events are observed around masses of 119, 126, and 320 GeV, making the observed limits weaker than expected in the absence of a signal.