Research Papers in Physics and Astronomy


Date of this Version



Physics Letters B 776 (2018) 355–378


© 2017 The Author.

Open access


The cross sections for the production of ttbb and ttjj events and their ratio σttbbttjj are measured using data corresponding to an integrated luminosity of 2.3fb−1 collected in pp collisions at √s = 13 TeV with the CMS detector at the LHC. Events with two leptons (e or μ) and at least four reconstructed jets, including at least two identified as b quark jets, in the final state are selected. In the full phase space, the measured ratio is 0.022 ± 0.003(stat) ± 0.006(syst), the cross section σttbb is 4.0 ± 0.6(stat) ±1.3(syst) pb and σttjj is 184 ± 6(stat) ± 33(syst) pb. The measurements are compared with the standard model expectations obtained from a powheg simulation at next-to-leading-order interfaced with pythia.