Measurement of the underlying event using the Drell-Yan process in proton-proton collisions at $\sqrt{s} = 13~\mathrm{TeV}$

This article presents a measurement of the underlying event activity, in proton-proton collisions at a centre-of-mass energy of $13~\mathrm{TeV}$, performed using inclusive Z-boson events ($\mathrm{qq} \rightarrow \mu^+\mu^-$) collected by the CMS experiment at the Large Hadron Collider. The analyzed data corresponds to an integrated luminosity of $2.1~\mathrm{fb}^{-1}$. The Underlying event activity is quantified in terms of charged particle multiplicity and their scalar $p_{\rm T}$ sum in different topological regions defined with respect to the azimuthal direction of the two muons coming from the decay of the Z-boson. The distributions are unfolded to stable charged-particle level and are compared with prediction from various models at a centre-of-mass energy of $13~\mathrm{TeV}$, as well as with measurements at a centre-of-mass energy of $1.96~\mathrm{TeV}$ and $7~\mathrm{TeV}$ by the CDF and CMS experiments.