1997/01/27 by Ulrich Heinz, Heinz, Ulrich
Physics and Astronomy · #FOS: Physical sciences #High-Energy Particle Collisions Research #Nuclear Theory (nucl-th) #Quantum Chromodynamics and Particle Interactions #nucl-th
paper · pdf · doi:10.48550/arxiv.nucl-th/9701054
12 pages LaTex, 2 ps-figures; To appear in the proceedings of the 25th International Hirschegg Workshop on Properties of Nuclei and Nuclear Excitations, Jan 13-18, 1997 "QCD Phase Transitions"
arxiv created 1997/01/27 · openalex publication_date 1997/01/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
By measuring hadronic single-particle spectra and two-particle correlations in heavy-ion collisions, the size and dynamical state of the collision fireball at freeze-out can be reconstructed. I discuss the relevant theoretical methods and their limitations. By applying the formalism to recent pion correlation data from Pb+Pb collisions at CERN we demonstrate that the collision zone has undergone strong transverse growth before freeze-out (by a factor 2-3 in each direction), and that it expands both longitudinally and transversally. From the thermal and flow energy density at freeze-out the energy density at the onset of transverse expansion can be estimated from conservation laws. It comfortably exceeds the critical value for the transition to color deconfined matter.