https://doi.org/10.1140/epjc/s10052-023-11968-z
Regular Article - Theoretical Physics
Model dependence of the number of participant nucleons and observable consequences in heavy-ion collisions
1
Frankfurt Institute for Advanced Studies, 60438, Frankfurt am Main, Germany
2
Institut für Theoretische Physik, Goethe Universität Frankfurt, Max-von-Laue-Strasse 1, 60438, Frankfurt am Main, Germany
3
Xidian-FIAS international Joint Research Center, Giersch Science Center, 60438, Frankfurt am Main, Germany
4
Helmholtz Research Academy Hesse for FAIR (HFHF), GSI Helmholtz Center for Heavy Ion Physics, Campus Frankfurt, Max-von-Laue-Str. 12, 60438, Frankfurt, Germany
5
GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291, Darmstadt, Germany
a
manjunath@fias.uni-frankfurt.de
Received:
4
April
2023
Accepted:
27
August
2023
Published online:
8
September
2023
The centrality determination and the estimated fluctuations of number of participant nucleons 
in Au–Au collisions at 1.23 AGeV beam kinetic energy suffers from severe model dependencies. Comparing the Glauber Monte Carlo (MC) and UrQMD transport models, it is shown that is a strongly model dependant quantity. In addition, for any given centrality class, Glauber MC and UrQMD predicts drastically different distributions. The impact parameter b and the number of charged particles 
on the other hand are much more correlated and give an almost model independent centrality estimator. It is suggested that the total baryon number balance, from integrated rapidity distributions, can be used instead of in experiments. Preliminary HADES data show significant differences to both, UrQMD simulations and STAR data in this respect.
© The Author(s) 2023
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/.
