Abstract
The top quark pair production cross section $\left({\sigma}_{\mathrm{t}\overline{\mathrm{t}}}\right)$ is measured for the first time in pp collisions at a center-of-mass energy of 5.02 TeV. The data were collected by the CMS experiment at the LHC and correspond to an integrated luminosity of $27.4 pb^ {−1}$. The measurement is performed by analyzing events with at least one charged lepton. The measured cross section is ${\sigma}_{\mathrm{t}\overline{\mathrm{t}}}$, with a total relative uncertainty of 12%. The result is in agreement with the expectation from the standard model. The impact of the presented measurement on the determination of the gluon distribution function is investigated.