Charm tagging and the H -> W^+W^- -> l nu c j semi-leptonic channel (1006.1078v2)

Abstract: We introduce a method to discover the Higgs boson at the Large Hadron Collider (LHC) through its decay to W^+W^-, where one boson decays to leptons, and the other decays to c+jet. This mechanism is complementary to the decay into dileptons, but has the potential to measure the invariant mass peak of the Higgs boson, and to avoid large recently discovered QCD backgrounds from heavy flavor decays. In addition, this mechanism motivates the study and creation of a dedicated charm jet tagger at LHC experiments. Existing charm jet tagging, in the form of fakes to bottom jet tagging, provides sensitivity to a standard model Higgs boson that is comparable to WW fusion. A 50% charm tagging efficiency in the relevant kinematic range could allow an independent 5-sigma discovery of a 165 GeV Higgs boson in 7 fb^-1 of integrated luminosity at a 14 TeV machine, or exclusion with a 7 TeV collider.