Studying strangeness and baryon production in small systems through Ξ—hadron correlations using the ALICE detector

Jonatan Adolfsson,G David,T Ullrich,S Mukherjee,A Kalweit,P Garg,I.-K Yoo,Z Xu

doi:10.1051/epjconf/202225913015

Abstract

These proceedings summarise recent measurements of angular correlations between the Ξ baryon and identified hadrons in pp collisions at √S = 13 TeV using the ALICE detector. The results are compared with both string-based (PYTHIA8 with extensions) and core-corona (EPOS-LHC) models, to improve our understanding of strangeness and baryon production in small systems. The results favour baryon production through string junctions over diquark breaking, but the PYTHIA models fail at describing the relatively wide Ξ—strangeness jet peak, indicating stronger diffusion of strange quarks in data. On the other hand, EPOS-LHC is missing local conservation of quantum numbers, making it difficult to draw any conclusion about the core-corona model.

Highlights

Today, it is widely accepted that a quark–gluon plasma (QGP) is formed in heavy-ion collisions
To extract the part that is due to balancing charges, same-charge correlations were subtracted from those of opposite charge. This was measured for identified Ξ − π, Ξ − K,√Ξ − p, Ξ − Λ, and Ξ − Ξ pairs using approximately 8 · 108 minimum-bias pp events at s = 13 TeV recorded by the ALICE detector [6]
PYTHIA8 Monash underestimates the difference between opposite- and same-sign (OS-SS) correlations, which is better described by the other models or tunes

Summary

Introduction

It is widely accepted that a quark–gluon plasma (QGP) is formed in heavy-ion collisions. What is not yet understood, is that several QGP key signatures have been observed in small systems such as high-multiplicity proton–proton (pp) collisions, where the QGP is not expected to form One such signature is the enhanced yields of multi-strange baryons, which seem to scale smoothly with system size [1]. Microscopic models based on colour strings are extended with new mechanisms for strange-baryon formation and other features to mimic collective behaviour. This approach is used in PYTHIA [2], where baryons in the standard configuration (Monash tune) are formed through diquark breaking.

Methods

Results

Conclusion