Measurement of the differential ttbar cross section in the dilepton channel at 8 TeV

Normalised differential top-quark pair production cross sections are measured in pp~collisions at a centre-of-mass energy of 8 TeV at the LHC with the CMS detector using data recorded in 2012 corresponding to an integrated luminosity of 12.2 $\mathrm{fb^{-1}}$. The measurements are performed in the dilepton decay channels ($\mathrm{e^+e^-}$, $\mu^+\mu^-$, and $\mu^{\pm} \mathrm{e^{\mp}}$). The $\mathrm{t \bar t}$ production cross section is measured as a function of kinematic properties of the final-state charged leptons and jets associated to b quarks, as well as those of the top quarks and the $\mathrm{t \bar t}$ system. The data are compared with several predictions from perturbative QCD calculations up to approximate next-to-next-to-leading-order precision. No significant deviations from the standard model are observed.