Measurement of the charged particle nuclear modification factor in PbPb collisions at $\sqrt{s_{\rm NN}}=5.02~\mathrm{TeV}$

The nuclear modification factor, $R_{\rm AA}$, of charged particles produced in the $|\eta|<1$ pseudorapidity region is measured at $\sqrt{s_{\rm NN}}=5.02~\mathrm{TeV}$ using $404~\mu\mathrm{b}^{-1}$ of PbPb and $25.8~\mathrm{pb}^{-1}$ of pp data collected by the CMS experiment at the end of 2015. The $R_{\rm AA}$ is presented in several bins of collision centrality, over the transverse momentum range of $0.7-400~\mathrm{GeV}$. The measured $R_{\rm AA}$ in the $0-5\%$ most central collision class shows a maximum suppression by a factor of approximately $7.5$ in the $6-9~\mathrm{GeV}$ $p_\mathrm{T}$ region, followed by a rising trend up to the highest transverse momenta measured in the analysis. The measurement is compared to earlier results at lower collision energies, and to theory predictions.