Measurement of the $\mathrm{t}\bar{\mathrm{t}}$ production cross section, the top quark mass, and the strong coupling constant using events in the dilepton final state in pp collisions at $\sqrt{s}=13\;\mathrm{TeV}$

A measurement of the top quark-antiquark ($\mathrm{t}\bar{\mathrm{t}}$) pair production cross section in proton-proton collisions at a centre-of-mass energy of $13\;\mathrm{TeV}$ is presented. The data correspond to an integrated luminosity of 35.9 $\mathrm{fb}^{-1}$, recorded by the CMS experiment at the CERN LHC in 2016. Events containing two charged leptons are selected and the cross section is measured from a likelihood fit. For a fixed top quark mass parameter in the simulation of $172.5\;\mathrm{GeV}$ the fit yields a measured cross section $\sigma_{\mathrm{t}\bar{\mathrm{t}}}= 803 \pm 2 \; \mathrm {(stat)}\pm 25\;\mathrm{(syst)} \pm 20\;\mathrm{(lum)} \; \mathrm{pb}$, in agreement with the expectation from the standard model calculation at next-to-next-to-leading order (NNLO). A simultaneous fit of the cross section and the top quark mass parameter in the simulation is performed. The resulting cross section is used, together with the NNLO theory prediction, to determine the top quark mass and to extract a value of the strong coupling constant.