A search is described for a Higgs boson decaying into two photons, one of which has an internal conversion to a muon or an electron pair (ll gamma). The analysis is performed using proton-proton collision data recorded with the CMS detector at the LHC at a centre-of-mass energy of 8TeV, corresponding to an integrated luminosity of 19.7 fb(-1). The events selected have an opposite-sign muon or electron pair and a high transverse momentum photon. No excess above background has been found in the three-body invariant mass range 120 < m(ll gamma) < 150 GeV, and limits have been derived for the Higgs boson production cross section times branching fraction for the decay H -> gamma*gamma -> ll gamma, where the dilepton invariant mass is less than 20 GeV. For a Higgs boson with m(H) = 125 GeV, a 95% confidence level (CL) exclusion observed (expected) limit is 6.7 (5.9(-1.8)(+2.8)) times the standard model prediction. Additionally, an upper limit at 95% CL on the branching fraction of H -> (J/psi)gamma for the 125 GeV Higgs boson is set at 1.5 x10(-3).

Search for a Higgs boson decaying into γ*γ→ℓℓγ with low dilepton mass in pp collisions at √s=8 TeV

CIOCCI, MARIA AGNESE;Donato, S.;MESSINEO, ALBERTO MARIA;RIZZI, ANDREA;TONELLI, GUIDO EMILIO;Musich, M.;Bianchini, L.;Marini, A. C.;
2016-01-01

Abstract

A search is described for a Higgs boson decaying into two photons, one of which has an internal conversion to a muon or an electron pair (ll gamma). The analysis is performed using proton-proton collision data recorded with the CMS detector at the LHC at a centre-of-mass energy of 8TeV, corresponding to an integrated luminosity of 19.7 fb(-1). The events selected have an opposite-sign muon or electron pair and a high transverse momentum photon. No excess above background has been found in the three-body invariant mass range 120 < m(ll gamma) < 150 GeV, and limits have been derived for the Higgs boson production cross section times branching fraction for the decay H -> gamma*gamma -> ll gamma, where the dilepton invariant mass is less than 20 GeV. For a Higgs boson with m(H) = 125 GeV, a 95% confidence level (CL) exclusion observed (expected) limit is 6.7 (5.9(-1.8)(+2.8)) times the standard model prediction. Additionally, an upper limit at 95% CL on the branching fraction of H -> (J/psi)gamma for the 125 GeV Higgs boson is set at 1.5 x10(-3).
2016
Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Eroe, J.; Flechl,...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/838588
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