Naslov
Evidence for exclusive gamma gamma to W+W- production and constraints on anomalous quartic gauge couplings in pp collisions at sqrt(s) = 7 and 8 TeV

Autori
Khachatryan, Vardan ; ... ; Pleština, R. ; ... Godinović, Nikola ; Lelas, Damir ; Puljak, Ivica ; ... ; Antunović, Željko ; Kovač, Marko ; Brigljević, Vuko ; Kadija, Krešo ; Luetić, Jelena ; Mićanović, Saša ; Sudić, Lucija ; ... ; Morović, Srećko ; ... ; Ferenček, Dinko ; ... ; Đurić, Senka ; ... ; Woods, Nate

Izvornik
Journal of High Energy Physics (1029-8479) (2016); 119-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
High energy physics, Experimental particle physics, LHC, CMS, Standard Model

Sažetak
A search for exclusive or quasi-exclusive gamma gamma to W+W- production, via pp to p(*) W+W- p(*) to p(*) mu+/- e-/+ at sqrt(s) = 8 TeV, is reported using data corresponding to an integrated luminosity of 19.7 inverse femtobarns. Events are selected by requiring the presence of an electron-muon pair with large transverse momentum pt(mu+/- e-/+) > 30 GeV, and no associated charged particles detected from the same vertex. The 8 TeV results are combined with the previous 7 TeV results (obtained for 5.05 inverse femtobarns of data). In the signal region, 13 (2) events are observed over an expected background of 3.9 +/- 0.6 (0.84 +/-0.15) events for 8 (7) TeV, resulting in a combined excess of 3.4 standard deviations over the background-only hypothesis. The observed yields and kinematic distributions are compatible with the standard model prediction for exclusive and quasi-exclusive gamma gamma to W+W- production. Upper limits on the anomalous quartic gauge coupling operators a[W ; 0, C] (dimension-6) and f[M0, 1, 2, 3] (dimension-8), the most stringent to date, are derived from the measured dilepton transverse momentum spectrum.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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