dorsal/arxiv
View SchemaReview of QGP signatures - ideas versus observables
| Authors | E. L. Bratkovskaya, M. Bleicher, A. Dumitru, K. Paech, M. Reiter, S. Soff, H. Stöcker, H. Weber, M. van Leeuwen, W. Cassing |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/0401031 |
| URL | https://arxiv.org/abs/nucl-th/0401031 |
Abstract
We investigate hadron production and transverse hadron spectra in nucleus-nucleus collisions from 2 $A\cdot$GeV to 21.3 $A\cdot$TeV within two independent transport approaches (UrQMD and HSD) based on quark, diquark, string and hadronic degrees of freedom. The enhancement of pion production in central Au+Au (Pb+Pb) collisions relative to scaled $pp$ collisions (the 'kink') is described well by both approaches without involving a phase transition. However, the maximum in the $K^+/\pi^+$ ratio at 20 to 30 A$\cdot$GeV (the 'horn') is missed by $\sim$ 40%. Also, at energies above $\sim$ 5 A$\cdot$GeV, the measured $K^{\pm}$ $m_{T}$-spectra have a larger inverse slope than expected from the models. Thus the pressure generated by hadronic interactions in the transport models at high energies is too low. This finding suggests that the additional pressure - as expected from lattice QCD at finite quark chemical potential and temperature - might be generated by strong interactions in the early pre-hadronic/partonic phase of central heavy-ion collisions. Finally, we discuss the emergence of density perturbations in a first-order phase transition and why they might affect relative hadron multiplicities, collective flow, and hadron mean-free paths at decoupling.
{
"annotation_id": "3bba6a11-6a60-4d71-9fe6-9b6713de64a4",
"date_created": "2026-03-02T18:00:01.252000Z",
"date_modified": "2026-03-02T18:00:01.252000Z",
"file_hash": "0abca47cbd70031a654be97daf9e1622a8d6d39105699e7c9070e8c89b21afac",
"private": false,
"record": {
"abstract": "We investigate hadron production and transverse hadron spectra in\nnucleus-nucleus collisions from 2 $A\\cdot$GeV to 21.3 $A\\cdot$TeV within two\nindependent transport approaches (UrQMD and HSD) based on quark, diquark,\nstring and hadronic degrees of freedom. The enhancement of pion production in\ncentral Au+Au (Pb+Pb) collisions relative to scaled $pp$ collisions (the\n\u0027kink\u0027) is described well by both approaches without involving a phase\ntransition. However, the maximum in the $K^+/\\pi^+$ ratio at 20 to 30\nA$\\cdot$GeV (the \u0027horn\u0027) is missed by $\\sim$ 40%. Also, at energies above\n$\\sim$ 5 A$\\cdot$GeV, the measured $K^{\\pm}$ $m_{T}$-spectra have a larger\ninverse slope than expected from the models. Thus the pressure generated by\nhadronic interactions in the transport models at high energies is too low. This\nfinding suggests that the additional pressure - as expected from lattice QCD at\nfinite quark chemical potential and temperature - might be generated by strong\ninteractions in the early pre-hadronic/partonic phase of central heavy-ion\ncollisions. Finally, we discuss the emergence of density perturbations in a\nfirst-order phase transition and why they might affect relative hadron\nmultiplicities, collective flow, and hadron mean-free paths at decoupling.",
"arxiv_id": "nucl-th/0401031",
"authors": [
"E. L. Bratkovskaya",
"M. Bleicher",
"A. Dumitru",
"K. Paech",
"M. Reiter",
"S. Soff",
"H. St\u00f6cker",
"H. Weber",
"M. van Leeuwen",
"W. Cassing"
],
"categories": [
"nucl-th"
],
"title": "Review of QGP signatures - ideas versus observables",
"url": "https://arxiv.org/abs/nucl-th/0401031"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "dbd3c6af-8b2b-4a6d-bb37-15c921fcf81d",
"id": "arXiv Dataset IDs",
"type": "Model",
"variant": "snapshot-2026-03-01",
"version": "0.1.0"
},
"user_id": 1000002
}