EPJ

2021 Impact factor 3.131
EPJ A - Hadrons and Nuclei
Hadrons and Nuclei
Eur. Phys. J. A 3, 165-170

The quark condensate in relativistic nucleus-nucleus collisions

B. Friman1,2 - W. Nörenberg1,2 - V.D. Toneev1,3

1 Gesellschaft für Schwerionenforschung (GSI), D-64220 Darmstadt, Germany
2 Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany
3 Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia

Received: 4 December 1997 / Revised version: 31 July 1998 Communicated by W. Weise

Abstract
We compute the modification of the quark condensate $\langle \bar{q} q\rangle$ in relativistic nucleus-nucleus collisions and estimate the 4-volume, where the quark condensate is small ($\langle \bar{q}q\rangle/\langle\bar{q} q\rangle_0\leq$ 0.1-0.3) using hadron phase-space distributions obtained with the quark-gluon string model. As a function of the beam energy the 4-volume rises sharply at a beam energy $E_{lab}/A \simeq$ (2-5) GeV, remains roughly constant up to beam energies $\simeq 20$ GeV and rises at higher energies. At low energies the reduction of the condensate is mainly due to baryons, while at higher energies the rise of the 4-volume is due to the abundant mesons produced. Based on our results we expect that moderate beam energies on the order of 10 GeV per nucleon are favourable for studying the restoration of chiral symmetry in a baryon-rich environment in nucleus-nucleus collisions.

PACS
11.30.Rd Chiral symmetries - 24.80.+y Nuclear tests of fundamental interactions and symmetries - 24.85.+p Quarks, gluons, and QCD in nuclei and nuclear processes - 25.75.+q Relativistic heavy-ion collisions

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