https://doi.org/10.1140/epja/s10050-020-00307-5
Regular Article – Theoretical Physics
Understanding the energy dependence of 
in heavy ion collisions: interplay of volume and space-momentum correlations
1
Institut für Theoretische Physik, Goethe Universität Frankfurt, Max-von-Laue-Strasse 1, 60438, Frankfurt am Main, Germany
2
GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291, Darmstadt, Germany
3
John von Neumann-Institut für Computing, Forschungzentrum Jülich, 52425, Jülich, Germany
4
Helmholtz Research Academy Hesse for FAIR, Campus Frankfurt, Frankfurt, Germany
5
University of Sarajevo, Sarajevo, Bosnia and Herzegovina
Received:
23
June
2020
Accepted:
18
November
2020
Published online:
9
February
2021
The deuteron coalescence parameter in proton+proton and nucleus+nucleus collisions in the energy range of 
900–7000 GeV for proton + proton and 2–2760 GeV for nucleus + nucleus collisions is analyzed with the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) transport model, supplemented by an event-by-event phase space coalescence model for deuteron and anti-deuteron production. The results are compared to data by the E866, E877, PHENIX, STAR and ALICE experiments. The values are calculated from the final spectra of protons and deuterons. At lower energies, 
GeV, drops drastically with increasing energy. The calculations confirm that this is due to the increasing freeze-out volume reflected in 
. At higher energies, 
GeV, saturates at a constant level. This qualitative change and the vanishing of the volume suppression is shown to be due to the development of strong radial flow with increasing energy. The flow leads to strong space-momentum correlations which counteract the volume effect.
© The Author(s) 2020
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
