Multiplicity dependence of identified particle production in proton-proton collisions with ALICE

Abstract

The study of identified particle production as a function of transverse momentum (pT) and event multiplicity in protonproton (pp) collisions at different center-of-mass energies (√s) is a key tool for understanding similarities and differences between small and large collisions systems. We report on the production of π±, K±, K0 S , p(p), Λ(Λ), Ξ± and Ω± measured in pp collisions in a wide range of center-of-mass energies with ALICE [1]. The multiplicity dependence of identified particle yields is presented for √s = 7 and 13 TeV and discussed in the context of the results obtained in protonlead (p-Pb) and lead-lead (Pb-Pb) collisions, unveiling remarkable and intriguing similarities. The production rates of strange hadrons are observed to increase more than those of non-strange particles, showing an enhancement pattern with multiplicity which does not depend on the collision energy. Even if the multiplicity dependence of spectral shapes can be qualitatively described by commonly-used Monte Carlo (MC) event generators, the evolution of integrated yield ratios is poorly described by these models.