https://doi.org/10.1140/epjp/s13360-025-06319-8
Regular Article
Comparative analysis of charged particle distributions and model predictions for underlying events with track-based selection in 13 TeV pp collisions
1
Department of Physics, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, 11671, Riyadh, Saudi Arabia
2
Department of Physics, Abdul Wali Khan University Mardan, 23200, Mardan, Pakistan
3
Hubei Key Laboratory of Energy Storage and Power Battery, School of Optoelectronic Engineering, School of New Energy, Hubei University of Automotive Technology, 442002, Shiyan, People’s Republic of China
4
Department of Mathematics, Physics and Statistics, Faculty of Natural Sciences, University of Guyana, 101110, Georgetown, Guyana
5
Department of Electrical Engineering, College of Engineering, Qassim University, Unaizah, Saudi Arabia
6
Department of Physics, Faculty of Science, University of Tabuk, Tabuk, Kingdom of Saudi Arabia
a
ajaz@awkum.edu.pk
b
20220073@huat.edu.cn
Received:
22
December
2023
Accepted:
14
April
2025
Published online:
8
May
2025
In this study, we conduct a comprehensive analysis of charged particle distributions that are particularly sensitive to underlying events. We employ simulations from three distinct models: EPOS4, Pythia8.3, and QGSJETII. These simulations are subsequently compared to experimental measurements obtained by the ATLAS experiment in proton–proton collisions at a center-of-mass energy of 
TeV. The analysis is conducted under specific kinematic conditions, with a focus on physical observables within the region defined by 
and 
GeV. A comparison of model predictions with data reveals that EPOS4 and Pythia8.3 consistently provide favorable results for various distributions, including mean charged particle densities, mean multiplicities, and average transverse momentum. The QGSJETII-04 model performs well at low 
and low 
, but under-predicts data in some distributions. EPOS4 stands out as having more accurate results, attributed to its detailed treatment of parton saturation and hydrodynamic effects, while Pythia8.3 benefits from parameters such as color reconnection and multi-parton interaction. The QGSJET focuses on cosmic-ray air showers and less on collective effects, highlighting the need for careful model selection to accurately represent particle collision physics. Furthermore, we employ a thermodynamically consistent Tsallis distribution function to extract parameter values for comparison purposes. Our findings reveal that the parameter values extracted from the fit function align more closely with the data for the EPOS4 and Pythia8.3 models, indicating that these two models provide a better representation of the experimental observations as compared to QGSJETII-04.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
