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). (C) 2015 CERN for the benefit of the CMS Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license

Search for a Higgs boson decaying into gamma*gamma -> ll gamma with low dilepton mass in pp collisions at root s=8 TeV

CAPPELLO, GIGI;CHIORBOLI, MASSIMILIANO;COSTA, Salvatore;GIORDANO, FERDINANDO;POTENZA, Renato Carlo;TRICOMI, Alessia Rita;TUVE', Cristina Natalina;
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). (C) 2015 CERN for the benefit of the CMS Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license
2016
CMS, Dalitz decay, Higgs boson, Physics, Nuclear and High Energy Physics.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/310412
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