Measurement of the Jet Multiplicity in Dileptonic Top-Quark Pair Events at $\sqrt{s}=$~8~TeV

Jet multiplicity distributions in top pair events are measured in pp collisions at $\sqrt{s}=$8~TeV with the CMS detector using a dataset corresponding to 19.6 fb$^{-1}$. The normalized differential top antitop quark cross section is measured in the dileptonic $\mathrm{t\bar{t}}$ decay channels as a function of the jet multiplicity for different jet transverse momentum ($p_T$) thresholds. Furthermore, the distribution of the fraction of events without additional jets above a threshold is measured as functions of the additional jets $p_T$ and of the scalar sum of the transverse momenta of all additional jets. The data are compared to several predictions from perturbative QCD calculations.