TY  - JOUR
A1  - Moreau, Pierre
A1  - Palmese, Alessia
A1  - Cassing, Wolfgang
A1  - Seifert, Eduard
A1  - Steinert, Thorsten
A1  - Bratkovskaya, Elena L.
T1  - Evidence for chiral symmetry restoration in heavy-ion collisions
T2  - Nuclear Physics A
N2  - We study the effect of the chiral symmetry restoration (CSR) on heavy-ion collisions observables in the energy range sNN=3–20GeV within the Parton-Hadron-String Dynamics (PHSD) transport approach. The PHSD includes the deconfinement phase transition as well as essential aspects of CSR in the dense and hot hadronic medium, which are incorporated in the Schwinger mechanism for particle production. Our systematic studies show that chiral symmetry restoration plays a crucial role in the description of heavy-ion collisions at sNN=3–20GeV, realizing an increase of the hadronic particle production in the strangeness sector with respect to the non-strange one. Our results provide a microscopic explanation for the horn structure in the excitation function of the K+/π+ ratio: the CSR in the hadronic phase produces the steep increase of this particle ratio up to sNN≈7GeV, while the drop at higher energies is associated to the appearance of a deconfined partonic medium. Furthermore, the appearance/disappearance of the horn structure is investigated as a function of the system size. We additionally present an analysis of strangeness production in the (T,μB)-plane (as extracted from the PHSD for central Au+Au collisions) and discuss the perspectives to identify a possible critical point in the phase diagram.
KW  - Chiral symmetry restoration
KW  - relativistic heavy-ion collisions
KW  - quark-gluon plasma
KW  - string fragmentation
KW  - strangeness enhancement
KW  - QCD phase diagram
Y1  - 2017
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/77330
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-773301
SN  - 0375-9474
VL  - 967
SP  - 836
EP  - 839
PB  - Elsevier
CY  - Amsterdam
ER  -