Measurement of top-quark pair production in association with charm quarks in proton–proton collisions at √s = 13 TeV with the ATLAS detector
Inclusive cross-sections or top-quark pair production in association with charm quarks are measured with proton-proton collision data at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 140 fb-1, collected with the ATLAS experiment at LHC between 2015 and 2018. The measurements are performed by requiring one or two charged leptons (electrons and muons), two b-tagged jets, and at least one additional jet in the final state. A custom flavor-tagging algorithm is employed for the simultaneous identification of b-jets and c-jets. In a fiducial phase space that replicates the acceptance of the ATLAS detector, the cross-sections for $$t\bar{t}$$ + ≥ 2c and $$t\bar{t}$$ + 1c production are measured to be $$1.28^{+0.27}_{-0.24}$$ pb and $$6.4^{+1.0}_{-0.9}$$ pb, respectively. The measurements are primarily limited by uncertainties in the modeling of inclusive $$t\bar{t}$$ and $$t\bar{t}$$ + $$b\bar{b}$$ production, in the calibration of the flavor-tagging algorithm, and by data statistics. Cross-section predictions from various $$t\bar{t}$$ simulations are largely consistent with the measured cross-section values, though all underpredict the observed values by 0.5 to 2.0 standard deviations. In a phase-space volume without requirements on the $$t\bar{t}$$ decay products and the jet multiplicity, the cross-section ratios of $$t\bar{t}$$ + ≥ 2c and $$t\bar{t}$$ + 1c to total $$t\bar{t}$$ + jets production are determined to be (1.23 ± 0.25)% and (8.8 ± 1.3)%.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Contributing Organization:
- The ATLAS Collaboration
- Grant/Contract Number:
- AC02-05CH11231
- OSTI ID:
- 2511059
- Journal Information:
- Physics Letters. B, Journal Name: Physics Letters. B Vol. 860; ISSN 0370-2693
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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