Multiplicity dependence of identified particle production in pp collisions with ALICE (1704.04737v2)

Abstract: The study of identified particle production as a function of transverse momentum ($p_{\text{T}}$) and event multiplicity in proton-proton (pp) collisions at different center-of-mass energies ($\sqrt{s}$) is a key tool for understanding similarities and differences between small and large collisions systems. We report on the production of $\pi^{\pm}$, $K^{\pm}$, $K^{0}_{S}$, $p (\bar{p})$, $\Lambda (\bar{\Lambda})$, $\Xi^{\pm}$ and $\Omega^{\pm}$ measured in pp collisions in a wide range of center-of-mass energies with ALICE. The multiplicity dependence of identified particle yields is presented for $\sqrt{s} = \textrm{7}$ and $13$ TeV and discussed in the context of the results obtained in proton-lead (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.