Centrality dependence of strange particle production in Pb-Pb collisions at s N N = 5.02 TeV

The centrality dependence of strange ( K S 0 , Λ + Λ ¯ ) and multistrange ( Ξ − + Ξ ¯ + , Ω − + Ω ¯ + ) hadron production is measured by ALICE in the Large Hadron Collider (LHC) lead-lead (Pb-Pb) collisions at a center-of-mass energy per nucleon pair s N N = 5.02 TeV, using the full dataset collected during the LHC Run 2 campaign in the years 2015 and 2018. This is the largest heavy-ion dataset analyzed to date at the LHC, and it allows for the extraction of transverse momentum ( p T ) spectra and p T -integrated yields with unprecedented precision, over a broad range of charged particle multiplicity densities ( 〈 d N ch / d η 〉 | η | < 0.5 ), probing regions where smaller collision system ( and p -Pb) results are also available. The p T spectra evolve with centrality, featuring higher 〈 p T 〉 in central events for all particles. The Λ / K S 0 ratio exhibits the distinctive baryon-to-meson enhancement in the intermediate p T region, with a maximum which is shifted to larger p T for more central collisions. The hadron-to-pion yield ratios are presented as a function of 〈 d N ch / d η 〉 | η | < 0.5 and compared to results from different collision systems and energies. A smooth connection from to Pb-Pb is observed, thus demonstrating that collision system or energy do not play a role in the multiplicity evolution of this observable. The previously reported enhancement of strangeness production in the multiplicity range probed in and p -Pb collisions saturates in the multiplicity range of Pb-Pb data. These results constitute a key test bench for theoretical models and a first comparison to the EPOS 4 generator is presented.