Pseudorapidity distributions of charged hadrons in proton-lead collisions at $\sqrt{s_{{}_{\mathrm{N}\mathrm{N}}}}=$ 5.02 and 8.16 TeV

The pseudorapidity distributions of charged hadrons in proton-lead collisions at nucleon-nucleon center-of-mass energies $\sqrt{s_{{}_{\mathrm{N}\mathrm{N}}}}=$ 5.02 and 8.16 TeV are presented. The measurements are based on data samples collected by the CMS experiment at the LHC. The number of primary charged hadrons produced in non-single-diffractive proton-lead collisions is determined in the pseudorapidity range $\mathrm{\mid }{\eta }_{\mathrm{l}\mathrm{a}\mathrm{b}}\mathrm{\mid }<$ 2.4. The charged-hadron multiplicity distributions are compared to the predictions from theoretical calculations and Monte Carlo event generators. In the center-of-mass pseudorapidity range $\mathrm{\mid }{\eta }_{\mathrm{c}\mathrm{m}}\mathrm{\mid }<0.5$, the average charged-hadron multiplicity densities $<\mathrm{d}{N}_{\mathrm{c}\mathrm{h}}\mathrm{/}\mathrm{d}{\eta }_{\mathrm{c}\mathrm{m}}>$$\vert_{|\eta_{$\mathrm{c}\mathrm{m}$}| < 0.5}$are17.31$\pm$0.01(stat)$\pm$0.59(syst)and20.10$\pm$ 0.01 (stat) $\pm$ 0.85 (syst) at $\sqrt{s_{{}_{\mathrm{N}\mathrm{N}}}}=$ 5.02 and 8.16 TeV, respectively. The particle densities per participant nucleon are compared to similar measurements in proton-proton, proton-nucleus, and nucleus-nucleus collisions.