Search for Invisible Decays of a Higgs Boson Produced in Association with a Z Boson in ATLAS

G. Aad, B. Abbott, J. Abdallah, S. Abdel Khalek, O. Abdinov, R. Aben, B. Abi, Mogens Dam, Jørgen Beck Hansen, Jørn Dines Hansen, Stefania Xella, Gorm Aske Gram Krohn Galster, Peter Henrik Hansen, Troels Christian Petersen, Lotte Ansgaard Thomsen, Sascha Mehlhase, Morten Dam Jørgensen, Almut Maria Pingel, Ask Emil Løvschall-Jensen, Alejandro Alonso DiazJames William Monk, Lars Egholm Pedersen, Graig Wiglesworth

117 Citationer (Scopus)

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 <mH <400 GeV, produced in association with a Z boson and decaying to invisible particles.

OriginalsprogEngelsk
Artikelnummer201802
TidsskriftPhysical Review Letters
Vol/bind112
Antal sider19
ISSN0031-9007
StatusUdgivet - 20 maj 2014

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