Charged-particle production in pp collisions at 13.6 TeV and Pb-Pb collisions at 5.36 TeV with ALICE

Abstract

The first measurements of the charged-particle pseudorapidity density, $\mathrm{d}{N}_{\mathrm{ch}}/\mathrm{d}\eta$, in proton-proton (pp) collisions at $\sqrt{s}=$ 13.6 TeV and in lead-lead (Pb-Pb) collisions at $\sqrt{s_{\mathrm{NN}}}=$ 5.36 TeV are presented. The analysis is based on Run 3 data recorded in 2022 and 2023, using the upgraded ALICE detector at the LHC. The average charged-particle pseudorapidity density $⟨\mathrm{d}{N}_{\mathrm{ch}}/\mathrm{d}\eta ⟩$ in pp collisions was measured at midrapidity ($|\eta |<$0.5) with the upgraded central barrel detectors, such as the Inner Tracking System and the Time Projection Chamber and, at forward pseudorapidity ($-$3.6 $<|\eta |<-$ 2.4), using the newly installed Muon Forward Tracker (MFT). For Pb-Pb collisions, the measurement was performed in different centrality classes, ranging from the most central 0-5$\%$) to the peripheral (70-80$\%$) collisions.

Contribution to the 2025 QCD session of the 59th Rencontres de Moriond, 30 Mar - 6 April, 2025, 4 pages, 2 captioned figures