A search for evidence of invisible-particle decay modes of a Higgs boson produced in association with a Z boson at the Large Hadron Collider is presented. No deviation from the standard model expectation is observed in 4.5 fb-1 (20.3 fb-1) of 7 (8) TeV pp collision data collected by the ATLAS experiment. Assuming the standard model rate for ZH production, an upper limit of 75\%, at the 95\% confidence level is set on the branching ratio to invisible-particle decay modes of the Higgs boson at a mass of 125.5 GeV. The limit on the branching ratio is also interpreted in terms of an upper limit on the allowed dark matter-nucleon scattering cross section within a Higgs-portal dark matter scenario. Within the constraints of such a scenario, the results presented in this Letter provide the strongest available limits for low-mass dark matter candidates. Limits are also set on an additional neutral Higgs boson, in the mass range 110 <mH <400 GeV, produced in association with a Z boson and decaying to invisible particles.

Search for invisible decays of a Higgs boson produced in association with a Z boson in ATLAS / Aad, G; Aloisio, Alberto; Alviggi, Mariagrazia; Canale, Vincenzo; Chiefari, Giovanni; DELLA VOLPE, Domenico; Merola, Leonardo; Conventi, Francesco; DELLA PIETRA, Massimo; Giordano, Raffaele; Rossi, Elvira; SANCHEZ PINEDA, ARTURO RODOLFO; Carlino, Gianpaolo; de Asmundis, Riccardo; Di Donato, Camilla; Doria, Alessandra; Iengo, Paolo; Izzo, Vincenzo; Sekhniaidze, Givi; Et, A. l.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 112:20(2014). [10.1103/PhysRevLett.112.201802]

Search for invisible decays of a Higgs boson produced in association with a Z boson in ATLAS

ALOISIO, ALBERTO;ALVIGGI, MARIAGRAZIA;CANALE, VINCENZO;CHIEFARI, GIOVANNI;DELLA VOLPE, DOMENICO;MEROLA, LEONARDO;DELLA PIETRA, MASSIMO;GIORDANO, RAFFAELE;Rossi, Elvira;SANCHEZ PINEDA, ARTURO RODOLFO;
2014

Abstract

A search for evidence of invisible-particle decay modes of a Higgs boson produced in association with a Z boson at the Large Hadron Collider is presented. No deviation from the standard model expectation is observed in 4.5 fb-1 (20.3 fb-1) of 7 (8) TeV pp collision data collected by the ATLAS experiment. Assuming the standard model rate for ZH production, an upper limit of 75\%, at the 95\% confidence level is set on the branching ratio to invisible-particle decay modes of the Higgs boson at a mass of 125.5 GeV. The limit on the branching ratio is also interpreted in terms of an upper limit on the allowed dark matter-nucleon scattering cross section within a Higgs-portal dark matter scenario. Within the constraints of such a scenario, the results presented in this Letter provide the strongest available limits for low-mass dark matter candidates. Limits are also set on an additional neutral Higgs boson, in the mass range 110
2014
Search for invisible decays of a Higgs boson produced in association with a Z boson in ATLAS / Aad, G; Aloisio, Alberto; Alviggi, Mariagrazia; Canale, Vincenzo; Chiefari, Giovanni; DELLA VOLPE, Domenico; Merola, Leonardo; Conventi, Francesco; DELLA PIETRA, Massimo; Giordano, Raffaele; Rossi, Elvira; SANCHEZ PINEDA, ARTURO RODOLFO; Carlino, Gianpaolo; de Asmundis, Riccardo; Di Donato, Camilla; Doria, Alessandra; Iengo, Paolo; Izzo, Vincenzo; Sekhniaidze, Givi; Et, A. l.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 112:20(2014). [10.1103/PhysRevLett.112.201802]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/616516
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