CMS-PAS-HIN-23-007

CMS-PAS-HIN-23-007
Pseudorapidity distributions of charged hadrons in PbPb collisions at $\sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} =$ 5.36 TeV
CMS Collaboration
18 September 2023

Abstract: 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 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 $\pm$ 0.03 $\mu$ 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 (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.
Links: CDS record (PDF) ; CADI line (restricted) ; These preliminary results are superseded in this paper, Submitted to PLB. The superseded preliminary plots can be found here.

CMS Publications