New insights into strangeness production in pp collisions with ALICE at the LHC

Abstract

The observed increase of (multi-)strange hadron yields relative to non-strange hadron yields with the charged-particle multiplicity measured in pp collisions is reminiscent of the heavy-ion phenomenology but still remains to be understood. ALICE is addressing this open question exploiting different multi-differential techniques. In pp collisions the emission of leading baryons at very forward rapidity reduces the initial effective energy available for particle production with respect to the full center-of-mass energy. The production of $\Xi$ multi-strange baryons is studied as a function of the particle multiplicity measured at midrapidity and of the very forward energy detected by ALICE Zero Degree Calorimeters. To study the relative contribution to strange hadron production from hard and soft QCD processes, the angular correlation between high-momentum charged particles and strange hadrons is studied. The toward- and transverse-to-leading yield of K$^{0}_{\textrm{s}}$ and $\Xi^{\pm}$ are measured as a function of the charged particle multiplicity. The results of these measurements are compared to expectations from state-of-the-art phenomenological models implemented in commonly used Monte Carlo event generators.