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

Abstract

A search is presented for a standard model-like Higgs boson decaying to the μ[superscript +]μ[superscript −] or e[superscript +]e[superscript −] 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[superscript −1] at a centre-of-mass energy of 7 TeV and 19.7 fb[superscript −1] at 8 TeV for the μ[superscript +]μ[superscript −] search, and of 19.7 fb[superscript −1] at 8 TeV for the e[superscript +]e[superscript −] 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[superscript +]μ[superscript −], the observed (expected) upper limit on the production rate is found to be 7.4 (6.5[+2.8 over −1.9]) times the standard model value. This corresponds to an upper limit on the branching fraction of 0.0016. Similarly, for e[superscript +]e[superscript −], an upper limit of 0.0019 is placed on the branching fraction, which is ≈3.7 × 10[superscript 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.