Measurement of $\sigma(t\bar{t}b\bar{b})/\sigma(t\bar{t}jj) $ in pp collisions at $\sqrt{s}$ = 8 TeV

¯b¯The cross-section ratio σ (ttb¯)/σ (ttjj ) is measured in the dilepton decaymode, using a data sample corresponding to an integrated luminosity of 19.6fb−1 collected in pp collisions at 8 TeV with the CMS detector at the LHC.¯b¯The cross-section ratio σ (ttb¯)/σ (ttjj ) is measured in the visible phase spacecorresponding to the detector acceptance, and corrected to particle level. Themeasurement is performed by means of a fit to be measured b-jet discriminatordistribution of first and second additional jets of dileptonic top quark pair candidates with at least four reconstructed jets. The result of the measurement,√2.6 ± 0.4(stat.) ± 0.3(syst.)% at s = 8 TeV.