2002/02/19 by Ralf Rapp, R. Rapp, E. V. Shuryak +3
Mathematics · Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Nuclear Theory (nucl-th) #Quantum Chromodynamics and Particle Interactions #Stochastic processes and statistical mechanics #hep-ph #nucl-th
paper · pdf · doi:10.48550/arxiv.nucl-th/0202059
10 pages LaTeX including 8 eps-figures, Invited talk by first author at International Workshop XXX on Gross Properties of Nuclei and Nuclear Excitations, Hirschegg (Austria), 13.-19.01.02
arxiv created 2002/02/19 · openalex publication_date 2002/02/19 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The evolution of (non-strange) antibaryon abundances in the hadronic phase of central heavy-ion collisions is studied within a thermal equilibrium framework, based on the well-established picture of subsequent chemical and thermal freezeout. Due to large annihilation cross sections, antiprotons are, a priori, not expected to comply with this scheme. However, we show that a significant regeneration of their abundance occurs upon inclusion of the inverse reaction of multipion fusion, nππ→ p p (with nπ=5-6), necessary to ensure detailed balance. Especially at SPS energies, the build-up of large pion-chemical potentials between chemical and thermal freezeout reinforces this mechanism, rendering the p/p ratio in reasonable agreement with the observed one (reflecting chemical freezeout). Explicit solutions of the pertinent rate equation, which account for chemical off-equilibrium effects, corroborate this explanation.