Analysis strategy for the SM Higgs boson search in the four-lepton final state in CMS

Abstract. The current status of the searches for the SM Higgs boson in the H→ZZ(∗)→4 ` decay channel with the CMS experiment [1] is presented. The selection cuts for suppressing the backgrounds while keeping very high signal efficiencies are described, along with the data-driven algorithms implemented to estimate the background yields and the systematic uncertainties. With an integrated luminosity of 1.66 fb−1, upper limits at 95 % CL on the SM-like Higgs cross section × branching ratio exclude cross sections from about one to two times the expected value from the Standard Model in the range 150 < mH < 420 GeV. No evidence for the existence of the SM Higgs boson has been found so far. 1 Signal and backgrounds The H → ZZ → 4 ` analysis described here considers three final states (4e, 4µ, 2e2µ) over a Higgs boson mass range 100 < mH < 600 GeV/c2. The signature of signal events is very clean: two pairs of same-flavour, opposite-charge, high-pT isolated leptons pointing to the same reconstructed vertex are looked for. Mass constraints can be set on the dilepton invariant mass: also at low mH, at least one Z bo