Speaker
Description
The study of the production of particles of different masses as a function of event multiplicity is a key tool for understanding the soft QCD processes and hadronization. In this talk, we report ALICE results on transverse momentum spectra and yields of $\pi$, K, p, $K^{0}_{S}$, $\Lambda$, $\Xi$ and $\Omega$ measured in pp, p-A, and A-A collisions, including the recently published results in Pb-Pb and Xe-Xe collisions at $\sqrt{s_{\rm NN}} = 5.02$ and $5.44$ TeV, respectively. Particle spectra and ratios as measured in pp and A-A collisions are compared at similar charged-particle multiplicity densities ($\langle{\rm d}N_{\rm ch}/{\rm d}\eta\rangle$), and, for A-A collisions, at different initial eccentricities. Results on the hadron abundances measured in high-multiplicity pp collisions at $\sqrt{s}=13$ TeV as a function of event shape will be shown. In addition, to better understand the contribution of the event multiplicity to the observed enhancement of strange particles in pp, two new complementary analyses have been performed. The first classifies events according to the anti-correlation between mid-rapidity multiplicity and the energy deposited in the ALICE Zero Degree Calorimeters. The second exploits the angular correlation between strange and high-$p_{\rm T}$ charged hadrons to distinguish in-jet and out-of-jet strangeness production. Results indicate that strangeness enhancement correlates with the growth of the underlying event, which can be selected by employing a forward-rapidity classifier. Finally, results are discussed in the context of statistical hadronization models as well as pQCD-inspired models.
| Collaboration / Activity | ALICE |
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