Multiplicity dependent studies for strangeness production with ALICE

TL;DR

The ALICE experiment observed strangeness production enhancement across different collision systems and energies, revealing collective phenomena in small systems similar to those in large quark-gluon plasma formations.

Contribution

This study provides new insights into strangeness enhancement and collective effects in small collision systems, challenging previous assumptions about QGP formation only in large systems.

Findings

Strangeness yield to pion ratio increases with multiplicity across systems.

Enhancement is larger for particles with higher strangeness content.

Collective phenomena are observed in small collision systems.

Abstract

The ALICE experiment has studied strangeness production in different collision systems (pp, p-Pb, Xe-Xe and Pb-Pb) and energies. The ratio of the strange particle yield to pion yield as a function of multiplicity for different collision energies and systems follow a continuously increasing trend ("enhancement") from low multiplicity pp to high-multiplicity Pb-Pb collisions, independent of the initial collision energy and colliding particles. It is also observed that the enhancement is larger for the particles with larger strangeness content. Several other features that were observed in large collision systems and explained as due to collective phenomena related to the formation of the Quark Gluon Plasma (QGP) are also observed in small systems. This includes the enhancement of {\Lambda}/K^{0}_{S} yield ratios at intermediate p_{T}, the evolution of the particle p_{T} spectra with multiplicity towards higher multiplicity. These unexpected results have motivated to perform further studies using the ALICE detector for understanding the mechanisms responsible for such behaviour in small systems.