Strangeness production in small-collision systems with ALICE

TL;DR

This paper investigates the mechanisms behind strangeness production and enhancement in small collision systems like proton-proton collisions, highlighting the dominance of soft processes and the role of event multiplicity and effective energy.

Contribution

It provides new insights into the initial and final state effects influencing strangeness production, emphasizing the importance of soft processes and event classification methods.

Findings

Strangeness production increases with multiplicity in pp collisions.

Soft processes dominate the contribution to strangeness enhancement.

An anti-correlation exists between effective energy and strangeness production.

Abstract

We present the new studies which are performed with the aim of better understanding the production mechanisms for strange particles, and hence the strangeness enhancement phenomenon, in small-collision systems. In one of the recent studies, the very forward energy transported by beam remnants (spectators) and detected by the Zero Degree Calorimeters (ZDC) is used to classify events. The contribution of the effective energy and the particle multiplicity on strangeness production is studied using a multi-differential approach in order to disentangle initial and final state effects. In the second study, the origin of strangeness enhancement with multiplicity in pp has been further investigated by separating the contribution of soft and hard processes, such as jets, to strange hadron production. Techniques involving full jet reconstruction or two-particle correlations have been exploited. The results indicate that the increased relative strangeness production emerges from the growth of the underlying event and suggest that soft (transverse to leading) processes are the dominant contribution to strange hadron production and strangeness enhancement. Further it is also seen in pp collisions that strangeness production increases with midrapidity multiplicity and there exists an anti-correlation with the effective energy.