Multi-strange baryon production in pp, p-Pb and Pb-Pb collisions measured with ALICE at the LHC

Abstract

Multi-strange baryons are of particular interest in the understanding of particle production mechanisms, as their high strangeness content makes them susceptible to changes in the hadrochemistry of the colliding systems. In ALICE, these hyperons are reconstructed via the detection of their weak decay products, which are identified through their measured ionisation losses and momenta in the Time Projection Chamber. The production rates of charged $Ξ$ and $Ω$ baryons in proton-proton (pp), proton-lead (p-Pb) and lead-lead (Pb-Pb) collisions are reported as a function of $p_{\mathrm{T}}$. A direct comparison in the hyperon-to-pion ratios between the three collision systems is made as a function of event charged-particle multiplicity. The recently measured production rates in p-Pb interactions reveal an enhancement with increasing event multiplicity, consistent with a hierarchy dependent on the strangeness content of the hyperons. These results are discussed in the context of chemical equilibrium predictions, taking into account the extracted temperature parameter from a thermal model fit to the hadron yields in Pb-Pb data.