Strange and identified hadron production at the LHC with ALICE

TL;DR

This paper reports on measurements of identified hadron production in Pb-Pb and pp collisions at the LHC, revealing insights into the fireball's properties, expansion dynamics, and hadronisation mechanisms at unprecedented energies.

Contribution

It provides detailed spectra and yield measurements of various hadrons at the LHC, highlighting differences from lower-energy collisions and suggesting stronger collective effects.

Findings

More strongly expanding system compared to RHIC data

Higher pT baryon enhancement observed

Insights into hadronisation mechanisms at LHC energies

Abstract

The ALICE detector was designed to identify hadrons over a wide range of transverse momentum at mid-rapidity. Here measurements of light charged ({\pi}, K, p) and neutral ({\Lambda}, K0S) hadrons in Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV are presented with additional data from a pp reference at sqrt(s) = 7 TeV. Such measurements are crucial for understanding the properties of the fireball produced in heavy-ion collisions at the LHC. The particle-type dependence of the spectra and the yields of particles extracted give information on the expansion dynamics and chemical composition respectively. In addition studying the ratio of baryons to mesons may help in understanding the mechanisms by which hadronisation takes place. We find that, when comparing to data at sqrt(s_NN) = 200 GeV Au+Au collisions at RHIC, a more strongly expanding system is created with a similar relative population of hadron species. We also see that collective effects or complex mechanisms responsible for a relative enhancement of baryons have an influence at a much higher pT than was previously seen.