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

Measurements of the ZZ and WW final states in the mass range above the 2mZ and 2mW 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 predict...

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Hauptverfasser: Aad, Georges (VerfasserIn) , Anders, Christoph (VerfasserIn) , Andrei, George Victor (VerfasserIn) , Baas, Alessandra Edda (VerfasserIn) , Brandt, Oleg (VerfasserIn) , Djuvsland, Julia Isabell (VerfasserIn) , Dunford, Monica (VerfasserIn) , Geisler, Manuel Patrice (VerfasserIn) , Hanke, Paul (VerfasserIn) , Jongmanns, Jan (VerfasserIn) , Kluge, Eike-Erik (VerfasserIn) , Kugel, Andreas (VerfasserIn) , Lang, Valerie (VerfasserIn) , Meier, Karlheinz (VerfasserIn) , Schätzel, Sebastian (VerfasserIn) , Scharf, Veit (VerfasserIn) , Schmitt, Sebastian (VerfasserIn) , Schöning, André (VerfasserIn) , Schultz-Coulon, Hans-Christian (VerfasserIn) , Sosa Corral, David E. (VerfasserIn) , Stamen, Rainer (VerfasserIn) , Wessels, Martin (VerfasserIn)
Körperschaft: ATLAS Collaboration (VerfasserIn)
Dokumenttyp: Article (Journal)
Sprache:Englisch
Veröffentlicht: 17 July 2015
In: The European physical journal. C, Particles and fields
Year: 2015, Jahrgang: 75, Heft: 7, Pages: 1-34
ISSN:1434-6052
DOI:10.1140/epjc/s10052-015-3542-2
Online-Zugang:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1140/epjc/s10052-015-3542-2
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Verfasserangaben:ATLAS Collaboration*
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Zusammenfassung:Measurements of the ZZ and WW final states in the mass range above the 2mZ and 2mW 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 ZZ→4ℓ, ZZ→2ℓ2ν and WW→eνμν final states. The result is based on pp collision data collected by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 20.3 fb−1 at a collision energy of s√=8 TeV. Using the CLs method, the observed 95 % 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 gg→ZZ and gg→WW 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 % CL upper limit on ΓH/ΓSMH in the range 4.5–7.5 (6.5–11.2) using the same variations of the background K-factor. Assuming that the unknown gg→VV background K-factor is equal to the signal K-factor, this translates into an observed (expected) 95 % CL upper limit on the Higgs boson total width of 22.7 (33.0) MeV.
Beschreibung:*ATLAS Collaboration: G. Aad, C.F. Anders, V. Andrei, A. Baas, O. Brandt, J.I. Djuvsland, M. Dunford, M. Geisler, P. Hanke, J. Jongmanns, E.-E. Kluge, A. Kugel, V. Lang, K. Meier, S. Schaetzel, V. Scharf, S. Schmitt, A. Schoening, H.-C. Schultz-Coulon, D. Sosa, R. Stamen, M. Wessels [und 2801 weitere Personen]
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Beschreibung:Online Resource
ISSN:1434-6052
DOI:10.1140/epjc/s10052-015-3542-2