Measurements of $t\overline{t}$ cross sections in association with b jets and inclusive jets and their ratio using dilepton final states in pp collisions at $\sqrt{s}$ = 13 TeV

The cross sections for the production of $t\overline{t}b\overline{b}$ and $t\overline{t}jj$ events and their ratio $\sigma_{t\overline{t}b\overline{b}} / \sigma_{t\overline{t}jj}$ are measured using data corresponding to an integrated luminosity of 2.3 $fb^{−1}$collected in pp collisions at $\sqrt{s}$ = 13TeV 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 $0.022 \pm 0.003(stat) \pm 0.006(syst)$, the cross section $\sigma_{t\overline{t}b\overline{b}}$ is $4.0 \pm 0.6(stat) \pm 1.3(syst)pb$ and $\sigma_{t\overline{t}jj}$ is $184 \pm 6(stat) \pm 33(syst)pb$. The measurements are compared with the standard model expectations obtained from a powheg simulation at next-to-leading-order interfaced with pythia.