Abstract

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 a determination of 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 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 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.

Autore Pugliese

• Spagnolo Stefania Antonia , Gorini Edoardo , Ventura Andrea

Tutti gli autori

• G. AAD , G. CHIODINI , E. GORINI , M. PRIMAVERA , S. SPAGNOLO , A. VENTURA , ET AL.

Titolo volume/Rivista

THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS

Anno di pubblicazione

2015

ISSN

1434-6044

ISBN

Non Disponibile

Numero di citazioni Wos

29

Ultimo Aggiornamento Citazioni

28/04/2018

Numero di citazioni Scopus

33

Ultimo Aggiornamento Citazioni

28/04/2018

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile