Charged-particle production in pp collisions at 13.6 TeV and Pb-Pb collisions at 5.36 TeV with ALICE (2506.14989v1)

Abstract: The first measurements of the charged-particle pseudorapidity density, ${\rm d}N_{\rm{ch}}/{\rm d}\eta$, in proton-proton (pp) collisions at $\sqrt{s} =$ 13.6 TeV and in lead-lead (Pb-Pb) collisions at $\sqrt{s_{\rm{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 $\langle{\rm d}N_{\rm{ch}}/{\rm d}\eta\rangle$ 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.