Smallest drop of QGP: Thermodynamic properties in p-Pb collisions

TL;DR

This paper investigates whether quark-gluon plasma, typically formed in large heavy-ion collisions, can also form in smaller p-Pb collisions by analyzing thermodynamic properties with advanced hydrodynamic models and comparing results with experimental and lattice QCD data.

Contribution

It provides the first detailed hydrodynamic analysis of thermodynamic properties in p-Pb collisions at 5.02 TeV, supporting the formation of a collective quark-gluon plasma in small systems.

Findings

Evidence of collective behavior in high-multiplicity p-Pb collisions

Thermodynamic properties consistent with quark-gluon plasma formation

Comparison with lattice QCD supports deconfined phase presence

Abstract

The extreme conditions of temperature and density produced in ultrarelativistic collisions of heavy nuclei facilitate the formation of the most fundamental fluid in the universe, the deconfined phase of Quantum Chromodynamics called quark-gluon plasma. Despite the extensive experimental evidence collected over the past decade of its production in colliding systems such as Au-Au and Pb-Pb, establishing quark-gluon plasma formation in the collision of smaller systems, such as p-Pb, remains an open question. In this study, we describe the evolution of matter formed in p-Pb collisions at 5.02 TeV using a state-of-the-art hybrid model based on viscous relativistic hydrodynamics. We investigate the thermodynamic properties of the medium and final state observables. Our findings are compared with experimental data and first-principles calculations derived from lattice quantum chromodynamics. The results support the formation of a collective phase of strongly interacting matter in high-multiplicity p-Pb collisions.