Exploring Collective Effects in Small Collision Systems via Light-Flavour Particle Production in High-Multiplicity pp Collisions at $\sqrt{s}=$ 13 TeV in ALICE

Abstract

High-multiplicity pp and p-Pb collisions show signatures of radial and anisotropic flow, as well as the enhanced production of strange hadrons. These observations resemble phenomena seen in heavy-ion collisions, where a quark-gluon plasma (QGP) is formed, although their origin in small systems remains under discussion. This contribution presents ALICE Run 2 results on light-flavour hadron ($\pi$, K, p) production in high-multiplicity (HM) pp collisions at $\sqrt{s}=13$ TeV, where the charged-particle multiplicity reaches values comparable to peripheral or semi-peripheral Pb-Pb collisions. The multiplicity dependence of $\pi$, K, and p transverse momentum spectra, $p_{\mathrm{T}}$-differential and $p_{\mathrm{T}}$-integrated particle ratios, and mean transverse momenta ($⟨p_{\mathrm{T}}⟩$) is presented and compared with published results from other collision systems and energies, as well as with PYTHIA 8 and EPOS4 model calculations.

9 pages, 6 figures, QCD@Work 2026 proceedings