  The top quark pair production $\sigma_{t\bar{t}}$ is measured in pp
collisions at a center-of-mass energy of 5.02 TeV. The analyzed data have been
collected by the CMS experiment at the CERN LHC and correspond to an integrated
luminosity of 27.4 /pb. The measurement is performed by analyzing events with
at least one charged lepton. The measured cross section is 69.5 $\pm$ 8.4 pb.
The result is in agreement with the expectation from the standard model. The
impact of the presented measurement on the gluon distribution function is
illustrated through a quantum chromodynamic analysis at next-to-next-to-leading
order.
