A search for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass m < 30 GeV is presented. The analysis is performed using 139 fb−1 of proton–proton collision data, produced by the LHC at a centre-of-mass energy of 13 TeV and collected by the ATLAS experiment. Evidence for the H → γ process is found with a significance of 3.2 over the background- only hypothesis, compared to an expected significance of 2.1 for the Standard Model prediction. The best-fit value of the signal-strength parameter, defined as the ratio of the observed signal yield to the one expected in the Standard Model, is μ = 1.5 ± 0.5. The Higgs boson production cross-section times the H → γ branching ratio for m < 30 GeV is determined to be 8.7+2.8−2.7 fb.
De Castro, S., Fabbri, L., Gabrielli, A., Rinaldi, L., Semprini Cesari, N., Sioli, M., et al. (2021). Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at √s = 13 TeV with the ATLAS detector. PHYSICS LETTERS. SECTION B, 819, 1-22 [10.1016/j.physletb.2021.136412].
Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at √s = 13 TeV with the ATLAS detector
De Castro , S.;Fabbri , L.;Gabrielli , A.;Rinaldi , L.;Semprini Cesari , N.;Sioli , M.;Villa , M.;Zoccoli , A.;Bellagamba , L.;Boscherini , D.;Bruni , A.;Giacobbe , B.;Polini , A.;Sbarra , C.;Franchini , M.;Romano , M.;Valentinetti , S.;Alberghi , G. L.;Lasagni Manghi , F;Massa , L.;Vittori , C.;Cabras , G.;Todome , K.;Carratta , G.;Cavalli , N.;Clissa , L.;FABBRI,FEDERICA
2021
Abstract
A search for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass m < 30 GeV is presented. The analysis is performed using 139 fb−1 of proton–proton collision data, produced by the LHC at a centre-of-mass energy of 13 TeV and collected by the ATLAS experiment. Evidence for the H → γ process is found with a significance of 3.2 over the background- only hypothesis, compared to an expected significance of 2.1 for the Standard Model prediction. The best-fit value of the signal-strength parameter, defined as the ratio of the observed signal yield to the one expected in the Standard Model, is μ = 1.5 ± 0.5. The Higgs boson production cross-section times the H → γ branching ratio for m < 30 GeV is determined to be 8.7+2.8−2.7 fb.File | Dimensione | Formato | |
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