Measurement of $\sigma_{t\bar{t}b\bar{b}}/\sigma_{t\bar{t}jj}$ ratio at 13 TeV with the CMS Detector

The measurement of the cross section ratio $\sigma_{t\bar{t}b\bar{b}}/\sigma_{t\bar{t}jj}$ is presented using a data sample corresponding to an integrated luminosity of 2.3~$\rm{fb}^{-1}$ collected in pp collisions at \\ $\sqrt{s}$ = 13TeV with the CMS detector at the LHC. Events with two leptons and at least four reconstructed jets, including at least two identified as b quark jets, in the final state are selected. The measured ratio is $0.022 \pm 0.003$(stat.)$\pm0.006$(syst.) in the full phase space. The measured cross section $\sigma_{t\bar{t}b\bar{b}}$ is $3.9 \pm 0.6$(stat.)$\pm1.3$(syst.) pb and $\sigma_{t\bar{t}jj}$ is $176 \pm 5$(stat.)$ \pm 33 $(syst.) pb.