Measurements of tt¯ cross sections in association with b jets and inclusive jets and their ratio using dilepton final states in pp collisions at s=13TeV

Abstract The cross sections for the production of t t ¯ b b ¯ and t t ¯ jj events and their ratio σ t t ¯ b b ¯ / σ t t ¯ jj are measured using data corresponding to an integrated luminosity of 2.3 fb−1collected 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 σ t t ¯ b b ¯ is 4.0 ± 0.6 (stat) ± 1.3 (syst) pb and σ t t ¯ jj 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 .