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, A., Alviggi, M., Canale, V., Chiefari, G., DELLA VOLPE, D., Merola, L., Conventi, F., DELLA PIETRA, M., Giordano, R., Rossi, E., SANCHEZ PINEDA, A.R., Carlino, G., de Asmundis, R., Di Donato, C., Doria, A., Iengo, P., Izzo, V., Sekhniaidze, G., 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 110I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
