Naslov
Measurement of double-differential cross sections for top quark pair production in pp collisions at sqrt(s) = 8 TeV and impact on parton distribution functions

Autori
Sirunyan, Albert ; ... ; Mesić, Benjamin ; Godinović, Nikola ; Puljak, Ivica ; Starodumov, Andrey ; Morović, Srećko ; Lelas, Damir ; Kovač, Marko ; Đurić, Senka ; Ferenček, Dinko ; Brigljević, Vuko ; Luetić, Jelena ; Antunović, Željko ; Kadija, Krešo ; Šuša, Tatjana ; ... ; Woods, Nate

Kolaboracija
CMS Collaboration

Izvornik
European physical journal C (1434-6044) 77 (2017); 459, 45

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

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

Sažetak
Normalized double-differential cross sections for top quark pair (t t-bar) production are measured in pp collisions at a centre-of-mass energy of 8 TeV with the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 19.7 inverse femtobarns. The measurement is performed in the dilepton e+/- mu-/+ final state. The t t-bar cross section is determined as a function of various pairs of observables characterizing the kinematics of the top quark and t t-bar system. The data are compared to calculations using perturbative quantum chromodynamics at next-to-leading and approximate next-to-next-to-leading orders. They are also compared to predictions of Monte Carlo event generators that complement fixed-order computations with parton showers, hadronization, and multiple-parton interactions. Overall agreement is observed with the predictions, which is improved when the latest global sets of proton parton distribution functions are used. The inclusion of the measured t t-bar cross sections in a fit of parametrized parton distribution functions is shown to have significant impact on the gluon distribution.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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