Centrality dependence of the charged-particle multiplicity density at mid-rapidity in Pb-Pb collisions at $\sqrt{s_{\mathrm{N}\mathrm{N}}}$ = 5.02 TeV

The pseudorapidity density of charged particles ($\mathrm{d}{N}_{\mathrm{c}\mathrm{h}}\mathrm{/}\mathrm{d}\eta$) at mid-rapidity in Pb-Pb collisions has been measured at a center-of-mass energy per nucleon pair of $\sqrt{s_{\rm NN}}$=5.02TeV\mathrm{.}Itincreaseswithcentralityandreachesavalueof$1943 \pm 54$in$|\eta|<0.5$forthe5$$\mathrm{d}$N_$\mathrm{c}\mathrm{h}$/$\mathrm{d}$\eta$asafunctionof$\sqrt{s_{\rm NN}}$ for the most central collisions is observed, steeper than that observed in proton-proton collisions and following the trend established by measurements at lower energy. The centrality dependence of $\mathrm{d}{N}_{\mathrm{c}\mathrm{h}}\mathrm{/}\mathrm{d}\eta$ as a function of the average number of participant nucleons, $⟨N_{\mathrm{p}\mathrm{a}\mathrm{r}\mathrm{t}}⟩$, calculated in a Glauber model, is compared with the previous measurement at lower energy. A constant factor of about 1.2 describes the increase in $\frac{2}{\langle N_$\mathrm{p}\mathrm{a}\mathrm{r}\mathrm{t}$ \rangle}\langle $\mathrm{d}$N_$\mathrm{c}\mathrm{h}$/$\mathrm{d}$\eta \rangle$from$\sqrt{s_{\rm NN}}$=2.76TeVto$\sqrt{s_{\rm NN}}$ = 5.02 TeV for all centrality intervals, within the measured range of 0-80% centrality. The results are also compared to models based on different mechanisms for particle production in nuclear collisions.