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.

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. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaboration. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - STAMPA. - 819:(2021), pp. 136412.1-136412.22. [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.;
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.
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 / De Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaboration. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - STAMPA. - 819:(2021), pp. 136412.1-136412.22. [10.1016/j.physletb.2021.136412]
De Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaboration
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/858192
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