Abstract

The pseudorapidity ($\eta$) distributions of charged hadrons are measured using data collected at the highest ever nucleon-nucleon center-of-mass energy of $\sqrt{s_\mathrm{NN}}$ = 5.36 TeV for collisions of lead-lead ions. The data were recorded by the CMS experiment at the LHC in 2022 and correspond to an integrated luminosity of 0.30 $\pm$ 0.03 $\mu$b$^{-1}$. Using the CMS silicon pixel detector, the yields of primary charged hadrons produced in the range $\vert\eta\vert$$\lt$ 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 $\eta$ density in the range $\vert\eta\vert$ $\lt$ 0.5 is found to be 2032 $\pm$ 91 (syst), with negligible statistical uncertainty. This result is consistent with an extrapolation from nucleus-nucleus collision data at lower center-of-mass energies. Comparisons are made to various Monte Carlo event generators and to previous measurements of lead-lead and xenon-xenon collisions at similar collision energies. These new data detail the dependence of particle production on the collision energy, initial collision geometry, and the size of the colliding nuclei.

Table 1

Data from Figure 1

10.17182/hepdata.153190.v1/t1

Charged-hadron $\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta$ distributions in PbPb collisions at 5.36 TeV for events in the 0--80%, 0--5% and 50--55% centrality class.
Table 2a

Data from Figure 2 (left)

10.17182/hepdata.153190.v1/t2

Charged-hadron $\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta$ in PbPb collisions at 5.36 TeV at midrapidity as a function of event centrality.
Table 2b

Data from Figure 2 (right)

10.17182/hepdata.153190.v1/t3

Charged-hadron $\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta/2A$ in PbPb collisions at 5.36 TeV at midrapidity as a function of event centrality.
Table 3a

Data from Figure 3 (left)

10.17182/hepdata.153190.v1/t4

Charged-hadron $\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta/N_{part}$ in PbPb collisions at 5.36 TeV at midrapidity as a function of $N_{part}$.
Table 3b

Data from Figure 3 (right)

10.17182/hepdata.153190.v1/t5

Charged-hadron $\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta/N_{part}$ in PbPb collisions at 5.36 TeV at midrapidity as a function of $N_{part}/2A$.

Table 1

Table 2a

Table 2b

Table 3a

Table 3b

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