2020/04/09 by Sourendu Gupta, Gupta, Sourendu, Debasish Mallick +7 · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Nuclear Experiment (nucl-ex) #Nuclear Theory (nucl-th) #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2004.04681
openalex publication_date 2020/04/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
High energy heavy-ion collisions in laboratory produce a form of matter that can test Quantum Chromodynamics (QCD), the theory of strong interactions, at high temperatures. One of the exciting possibilities is the existence of thermodynamically distinct states of QCD, particularly a phase of de-confined quarks and gluons. An important step in establishing this new state of QCD is to demonstrate that the system has attained thermal equilibrium. We present a test of thermal equilibrium by checking that the mean hadron yields produced in the small impact parameter collisions as well as grand canonical fluctuations of conserved quantities give consistent temperature and baryon chemical potential for the last scattering surface. This consistency for moments up to third order of the net-baryon number, charge, and strangeness is a key step in the proof that the QCD matter produced in heavy-ion collision attains thermal equilibrium. It is a clear indication for the first time, using fluctuation observables, that a femto-scale system attains thermalization. The study also indicates that the relaxation time scales for the system are comparable to or smaller than the life time of the fireball.