Investigating the origin of strangeness enhancement in small systems through multi-differential analyses

Francesca Ercolessi,(For The Alice Collaboration)

doi:10.1051/epjconf/202225911006

Francesca Ercolessi, (For The Alice Collaboration)

Open Access

https://doi.org/10.1051/epjconf/202225911006

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Journal: EPJ Web of Conferences	Publication Date: Jan 1, 2022
License type: CC BY 4.0

Affiliation: INFN Sezione di Bologna

Abstract

The main goal of the ALICE experiment is to study the physics of strongly interacting matter, including the properties of the quark-gluon plasma (QGP). The relative production of strange hadrons with respect to non-strange hadrons in heavy-ion collisions was historically considered as one of the signatures of QGP formation. However, measurements at the LHC in pp and p-Pb collisions have shown similar features to those observed in Pb-Pb, measuring an increase in the production of strange hadrons relative to pions with the charged-particle multiplicity in the event. In order to better understand the role of the event multiplicity to the observed enhancement in pp, two new complementary analyses have been performed. The first exploits the angular correlation between strange and high-pT hadrons in the event to classify in-jet and out-of-jet strangeness production. The second uses the concept of the effective energy available in the event for particle production which is estimated by an anti-correlation with the energy deposited in ALICE’s Zero Degree Calorimeters. The results suggest that strangeness enhancement emerges from the growth of the underlying event and is not connected to initial state properties.

Highlights

Strange particle production in heavy-ion collisions has proved to be an important observable to investigate the strongly interacting medium created in the collision
The main subdetectors used for particle identification (PID) and tracking include the six-layer high resolution Inner Tracking System (ITS) and the large volume Time Projection Chamber (TPC)
Two forward detectors placed on both sides of the ALICE interaction point, the V0 and the Zero Degree Calorimeters (ZDC), are used to classify events in multiplicity and energy event classes, respectively

Summary

Introduction

Strange particle production in heavy-ion collisions has proved to be an important observable to investigate the strongly interacting medium created in the collision. The ALICE experiment has studied strangeness production in small collision systems, such as p-Pb and pp, by measuring the ratio of strange particle yields to pion yields as a function of the charged-particle multiplicity produced in the event.

Results

Conclusion