Pseudorapidity distributions of charged hadrons in PbPb collisions at $\sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = 5.36$ TeV

The pseudorapidity ($\eta$) distributions of charged hadrons are measured using data collected at a record nucleon-nucleon center-of-mass energy of $\sqrt{\smash[b]{s_{_{\mathrm{NN}}}}}=5.36~\mathrm{TeV}$ for collisions of lead-lead (PbPb) ions. The data were recorded by the CMS experiment at the LHC in 2022 and correspond to an integrated luminosity of $0.3\pm0.03~\mu\mathrm{b}^{-1}$. Using the CMS silicon pixel detector, the yields of primary charged hadrons produced in the range $|\eta|<2.6$ are reported. The evolution of the midrapidity particle density as a function of collision centrality is also reported. In the $5\%$ most central collisions, the charged-hadron pseudorapidity density is found to be $2032 \pm 91~(\text{syst})$ in the range $|\eta| < 0.5$, with negligible statistical uncertainty. This result is consistent with an extrapolation from lower energy nucleus-nucleus collision data. Comparisons are made to various Monte Carlo event generators, and to previous measurements of PbPb and xenon-xenon collisions at similar collision energies. These observations detail the dependence of midrapidity particle production on the initial collision geometry, collision energy, and system size.