Search for a standard model-like Higgs boson in the μ^+μ^−and e^+e^−decay channels at the LHC

Abstract

A search is presented for a standard model-like Higgs boson decaying to the μ^+μ^- or e^+e^− final states based on proton–proton collisions recorded by the CMS experiment at the CERN LHC. The data correspond to integrated luminosities of 5.0 fb^(−1) at a centre-of-mass energy of 7 TeV and 19.7 fb^(−1) at 8 TeV for the μ^+μ^− search, and of 19.7 fb^(−1) at 8 TeV for the e^+e^− search. Upper limits on the production cross section times branching fraction at the 95% confidence level are reported for Higgs boson masses in the range from 120 to 150 GeV. For a Higgs boson with a mass of 125 GeV decaying to μ^+μ^−, the observed (expected) upper limit on the production rate is found to be 7.4 6.5_(−1.9)^(+2.8)) times the standard model value. This corresponds to an upper limit on the branching fraction of 0.0016. Similarly, for e^+e^−, an upper limit of 0.0019 is placed on the branching fraction, which is ≈3.7×10^5 times the standard model value. These results, together with recent evidence of the 125 GeV boson coupling to τ-leptons with a larger branching fraction consistent with the standard model, confirm that the leptonic couplings of the new boson are not flavour-universal.

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