Naslov
First measurement of the cross section for top quark pair production with additional charm jets using dileptonic final states in pp collisions at $\sqrt{;s}; = $ 13 TeV

Autori
Sirunyan, Albert M ; ... ; Antunović, Željko ; Brigljević, Vuko ; Ferenček, Dinko ; Giljanović, Duje ; Godinović, Nikola ; Kovač, Marko ; Lelas, Damir ; Majumder, Devdatta ; Puljak, Ivica ; Roguljić, Matej ; Starodumov, Andrey ; Đurić, Senka ; Šuša, Tatjana ; Šćulac, Toni ; ... ; Vetens, Wren

Kolaboracija
CMS Collaboration

Izvornik
Physics letters. B (0370-2693) 820 (2021); 136565, 40

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

Ključne riječi
High energy physics ; Experimental particle physics ; LHC ; CMS ; Radiation-hard detectors ; Si microstrip and pad detectors ; Radiation damage to detector materials (solid state) ; Particle tracking detectors (Solid-state detectors) ; radiation: damage ; CMS: upgrade ; tracking detector ; semiconductor detector: design ; semiconductor detector: microstrip ; performance ; Hadron-Hadron scattering (experiments) ; Top physics ; p p: scattering ; p p: colliding beams ; top: single production

Sažetak
The first measurement of the inclusive cross section for top quark pairs ($\mathrm{;t\bar{;t};};$) produced in association with two additional charm jets is presented. The analysis uses the dileptonic final states of $\mathrm{;t\bar{;t};};$ events produced in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 41.5 fb$^{;-1};$, recorded by the CMS experiment at the LHC. A new charm jet identification algorithm provides input to a neural network that is trained to distinguish among $\mathrm{;t\bar{;t};};$ events with two additional charm ($\mathrm{;t\bar{;t};c\bar{;c};};$), bottom ($\mathrm{;t\bar{;t};b\bar{;b};};$), and light-flavour or gluon ($\mathrm{;t\bar{;t};LL};$) jets. By means of a template fitting procedure, the inclusive $\mathrm{;t\bar{;t};c\bar{;c};};$, $\mathrm{;t\bar{;t};b\bar{;b};};$, and $\mathrm{;t\bar{;t};LL};$ cross sections are simultaneously measured, together with their ratios to the inclusive $\mathrm{;t\bar{;t};};$ + two jets cross section. This provides measurements of the $\mathrm{;t\bar{;t};c\bar{;c};};$ and $\mathrm{;t\bar{;t};b\bar{;b};};$ cross sections of 10.1 $\pm$ 1.2 (stat) $\pm$ 1.4 (syst) pb and 4.54 $\pm$ 0.35 (stat) $\pm$ 0.56 (syst) pb, respectively, in the full phase space. The results are compared and found to be consistent with predictions from two different matrix element generators with next-to-leading order accuracy in quantum chromodynamics, interfaced with a parton shower simulation.

Izvorni jezik
Engleski

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