Constraints on the off-shell Higgs boson signal strength in the high-mass <i>ZZ</i> and <i>WW</i> final states with the ATLAS detector



Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Aben, R, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abreu, R
et al (show 2812 more authors) (2015) Constraints on the off-shell Higgs boson signal strength in the high-mass <i>ZZ</i> and <i>WW</i> final states with the ATLAS detector. EUROPEAN PHYSICAL JOURNAL C, 75 (7). 335-.

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Abstract

Measurements of the <i>ZZ</i> and <i>WW</i> final states in the mass range above the [Formula: see text] and [Formula: see text] thresholds provide a unique opportunity to measure the off-shell coupling strength of the Higgs boson. This paper presents constraints on the off-shell Higgs boson event yields normalised to the Standard Model prediction (signal strength) in the [Formula: see text], [Formula: see text] and [Formula: see text] final states. The result is based on <i>pp</i> collision data collected by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 20.3 fb[Formula: see text] at a collision energy of [Formula: see text] TeV. Using the [Formula: see text] method, the observed 95 [Formula: see text] confidence level (CL) upper limit on the off-shell signal strength is in the range 5.1-8.6, with an expected range of 6.7-11.0. In each case the range is determined by varying the unknown [Formula: see text] and [Formula: see text] background K-factor from higher-order quantum chromodynamics corrections between half and twice the value of the known signal K-factor. Assuming the relevant Higgs boson couplings are independent of the energy scale of the Higgs boson production, a combination with the on-shell measurements yields an observed (expected) 95 [Formula: see text] CL upper limit on [Formula: see text] in the range 4.5-7.5 (6.5-11.2) using the same variations of the background K-factor. Assuming that the unknown [Formula: see text] background K-factor is equal to the signal K-factor, this translates into an observed (expected) 95 [Formula: see text] CL upper limit on the Higgs boson total width of 22.7 (33.0) MeV.

Item Type: Article
Additional Information: 34 pages plus author list + cover pages (50 pages total), 12 figures, 6 tables, submited to The European Physical Journal C, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG-2014-10/
Uncontrolled Keywords: ATLAS Collaboration, ATLAS Collaboration, ATLAS Collaboration
Depositing User: Symplectic Admin
Date Deposited: 24 Nov 2017 08:33
Last Modified: 05 Oct 2023 09:27
DOI: 10.1140/epjc/s10052-015-3542-2
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3012793