Constraints of the off-shell Higgs boson signal strength in the high-mass $ZZ$ and $WW$ final states with the ATLAS detector - Université Clermont Auvergne Accéder directement au contenu
Article Dans Une Revue European Physical Journal C: Particles and Fields Année : 2015

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

G. Aad (1) , S. Albrand (2) , J. Brown (2) , J. Collot (2) , S. Crépé-Renaudin (2) , P.A. Delsart (2) , C. Gabaldon (2) , M.H. Genest (2) , J.Y. Hostachy (2) , F. Ledroit-Guillon (2) , A. Lleres (2) , A. Lucotte (2) , F. Malek (2) , C. Monini (2) , J. Stark (2) , B. Trocmé (2) , M. Wu (2) , G. Rahal (3) , S. Abdel Khalek (4) , A. Bassalat (4) , C. Becot (4) , S. Binet (4) , C. Bourdarios (4) , D. Charfeddine (4) , J.B. de Vivie De Regie (4) , L. Duflot (4) , M. Escalier (4) , L. Fayard (4) , D. Fournier (4) , E.L. Gkougkousis (4) , J.-F. Grivaz (4) , T. Guillemin (4) , F. Hariri (4) , S. Henrot-Versillé (4) , J. Hrivnac (4) , L. Iconomidou-Fayard (4) , M. Kado (4) , A. Lounis (4) , N. Makovec (4) , C. Nellist (4) , L. Poggioli (4) , P. Puzo (4) , A. Renaud (4) , D. Rousseau (4) , G. Rybkin (4) , A.C. Schaffer (4) , E. Scifo (4) , L. Serin (4) , S. Simion (4) , R. Tanaka (4) , H.L. Tran (4) , D. Zerwas (4) , Z. Zhang (4) , Z. Barnovska (5) , N. Berger (5) , M. Delmastro (5) , L. Di Ciaccio (5) , T.K.O. Doan (5) , S. Elles (5) , T. Hryn’ova (5) , S. Jézéquel (5) , I. Koletsou (5) , R. Lafaye (5) , J. Leveque (5) , N. Massol (5) , G. Sauvage (5) , E. Sauvan (5) , O. Simard (5) , T. Todorov (5) , I. Wingerter-Seez (5) , D. Boumediene (6) , Emmanuel Busato (6) , D. Calvet (6) , S. Calvet (6) , J. Donini (6) , E. Dubreuil (6) , N. Ghodbane (6) , G. Gilles (6) , Ph. Gris (6) , H. Liao (6) , R. Madar (6) , D. Pallin (6) , S.M. Romano Saez (6) , C. Santoni (6) , D. Simon (6) , Timothée Theveneaux-Pelzer (6) , F. Vazeille (6) , L. Alio (1) , M. Barbero (1) , Y. Coadou (1) , C. Diaconu (1) , Sara Diglio (1) , F. Djama (1) , O. Duccu (1) , L. Feligioni (1) , J. Gao (1) , G.D. Hallewell (1) , F. Hubaut (1) , S.J. Kahn (1) , E. B. F. G. Knoops (1) , E. Le Guirriec (1) , J. Liu (1) , K. Liu (1) , D. Madaffari (1) , K. Mochizuki (1) , E. Monnier (1) , S. Muanza (1) , Y. Nagai (1) , E. Nagy (1) , P. Pralavorio (1) , A. Rozanov (1) , T. Serre (1) , M. Talby (1) , R.E. Ticse Torres (1) , E. Tiouchichine (1) , S. Tisserant (1) , J. Toth (1) , F. Touchard (1) , L. Vacavant (1)
G. Aad
D. Rousseau
Z. Zhang
N. Berger
T. Hryn’ova
S. Calvet
Y. Coadou

Résumé

Measurements of the $ZZ$ and $WW$ final states in the mass range above the $2m_Z$ and $2m_W$ thresholds provide a unique opportunity to measure the off-shell coupling strength of the Higgs boson. This paper presents a determination of the off-shell Higgs boson event yields normalised to the Standard Model prediction (signal strength) in the $ZZ \rightarrow 4\ell$, $ZZ\rightarrow 2\ell2\nu$ and $WW\rightarrow e\nu\mu\nu$ 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$^{\mathrm{-1}}$ at a collision energy of $\sqrt{s}=8$ TeV. Using the $CL_s$ 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 $gg\rightarrow ZZ$ and $gg\rightarrow WW$ background K-factor from higher-order QCD 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 production, a combination with the on-shell measurements yields an observed (expected) 95% CL upper limit on $\Gamma_H/\Gamma_H^{\mathrm{SM}}$ in the range 4.5--7.5 (6.5--11.2) using the same variations of the background K-factor. Assuming that the unknown $gg\rightarrow VV$ 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.

Dates et versions

in2p3-01122472 , version 1 (04-03-2015)

Identifiants

Citer

G. Aad, S. Albrand, J. Brown, J. Collot, S. Crépé-Renaudin, et al.. Constraints of the off-shell Higgs boson signal strength in the high-mass $ZZ$ and $WW$ final states with the ATLAS detector. European Physical Journal C: Particles and Fields, 2015, 75, pp.335. ⟨10.1140/epjc/s10052-015-3542-2⟩. ⟨in2p3-01122472⟩
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