  Normalised differential top-quark pair production cross sections are measured
in pp collisions at a centre-of-mass energy of 7 TeV at the LHC with the CMS
detector using data recorded in 2011 corresponding to an integrated luminosity
of 5.0 inverse femtobarns. The measurements are performed in the lepton+jets
decay channels (e+jets and mu+jets) and the dilepton decay channels (oppositely
charged ee, mu mu, and e mu). The t t-bar differential 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 t t-bar 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.
