In EPOS4, one distinguishes between primary and secondary interactions. The former refer to the multiple parallel scatterings happening (at high energies) instantaneously and which result in complex configurations composed of many strings, whereas the latter refer to subsequent interactions of the string decay products, which amounts to first a core-corona separation based on the string segments, and then the fluid formation, evolution, and decay of the core part.
The discussion of primary interactions covers two topics, namely the parallel scattering formalismn, developed in terms of abstract objects for single scatterings called "Pomerons", and the internal structure of the Pomerons, showing how the Pomeron is related to parton-parton cross sections expressed in terms of QCD diagrams.
EPOS4 overview
Revealing a deep connection between factorization and saturation: New insight into modeling high-energy proton-proton and nucleus-nucleus scattering in the EPOS4 framework
arXiv:2301.12517, published in Phys. Rev. C 108, 064903 (2023)
Internal Pomeron structure in terms of QCD (link between the multiple scattering formalism and QCD)
Perturbative QCD concerning light and heavy flavor in the EPOS4 framework
arXiv:2306.02396, published in Phys. Rev. C 108, 034904 (2023)
Very detailed and rigorous treatment of the multiple scattering formalism based on Pomerons
Parallel scattering, saturation, and generalized Abramovskii-Gribov-Kancheli (AGK) theorem in the EPOS4 framework, with applications for heavy-ion collisions at of 5.02 TeV and 200 GeV
arXiv:2310.09380, published in Phys. Rev. C 109, 034918 (2024)
Core-corona procedure and microcanonical hadronization in EPOS4
Core-corona procedure and microcanonical hadronization to understand strangeness enhancement in proton-proton and heavy ion collisions in the EPOS4 framework
arXiv:2306.10277, published in Phys. Rev. C 109, 014910 (2024)
Does charm flow, even in small systems?
Heavy flavor as a probe of hot QCD matter produced in proton-proton collisions
arXiv:2310.08684, published in Phys. Rev. D 109, 054011 (2024)
Systematic comparison of open heavy flavor data with EPOS4HQ simulations
Heavy flavour hadron production in relativistic heavy ion collisions at RHIC and LHC in EPOS4HQ
arXiv:2401.17096
Studying RHIC energies
Heavy ion collisions from of 62.4 GeV down to 4 GeV in the EPOS4 framework
arXiv:2401.11275
Studying second order cumulants of conserved charges in heavy-ion collisions
On the study of new proxies for second order cumulants of conserved charges in heavy-ion collisions with EPOS4
arXiv:2403.02306
A fast EPOS4 option, using parameterized fluid expansion
The EPOS4 approach for high energy collisions amounts to primary (parallel) scatterings, followed by a core-corona separation, with a hydrodynamic evolution of the core part, the latter one being very time-consuming, even for small systems. We provide a “shortcut” in the sense that the hydrodynamical evolution is replaced by a parameterized fluid expansion (PFE), without changing anything else. A relatively simple parameterization allows us to get results very close to the full simulation. The purpose of such a PFE option is the possibility of being used for applications where the speed is crucial, like in air shower simulations.
Flow observables in heavy ion collisions from 5TeV per nucleon down to 7.7GeV in the EPOS4 framework
The EPOS4 approach is based on a parallel primary scattering scenario, which should be employed (based on time scale arguments) for nucleus-nucleus collisions at very high energy, but also down to 20-30 GeV per nucleon. Below, even down to 4 GeV, parallel primary scatterings are at least partially relevant. We continue our effort to see to what extent the model is compatible with experimental data in heavy ion collisions from 5.02 TeV down to 7.7 GeV. We try to understand in which way the role of the different components (primary interactions, hydro evolution, hadronic cascade) changes when we go down in energy up to the point where the plasma component disappears. In this paper, we focus on flow observables.
System size dependence of flow harmonics in pp and heavy ion collisions at TeV energies in the EPOS4 framework
The EPOS4 approach is based on a (recently very much improved) parallel primary scattering scenario followed by a hydrodynamic expansion, for all systems, from small (proton-proton) to big ones (PbPb). Having already reported among others on identified particle spectra in recent publications (providing information about radial flow), we discuss here the system size dependence of flow harmonics, to better understand collectivity when going from big to small systems. The model is not in particular tuned for flow results, it is a “general purpose” approach and this paper is part of a bigger project where we simulate “everything” (soft/hard probes, small/big systems, low/high energy) with the same model, same version (EPOS4.0.0).
First detailed publication on EPOS 3, 2014
Analysing radial flow features in p-Pb and p-p collisions at several TeV by studying identified particle production in EPOS3
K. Werner, B. Guiot, Iu. Karpenko, T. Pierog
arXiv:1312.1233 Published in Phys.Rev. C89 (2014) 064903.
Publication details and Citations
First detailed publication on EPOS LHC, 2013
EPOS LHC: Test of collective hadronization with data measured at the CERN Large Hadron Collider
T Pierog, I Karpenko, JM Katzy, E Yatsenko, K Werner
arXiv:1306.0121 Published in Physical Review C 92 (2015) 034906
Publication details and Citations
First detailed publication on EPOS + hydro, 2010
Event-by-Event Simulation of the Three-Dimensional Hydrodynamic Evolution from Flux Tube Initial Conditions in Ultrarelativistic Heavy Ion Collisions
K. Werner, Iu. Karpenko, T. Pierog, M. Bleicher, K. Mikhailov
arXiv:1004.0805 Published in Phys.Rev. C82 (2010) 044904
Publication details and Citations
First publication on the core-corona procedure in EPOS, 2007
Core-corona separation in ultra-relativistic heavy ion collisions
Klaus Werner
arXiv:0704.1270 Published in Phys. Rev. Lett. 98 (2007) 152301
Publication details and Citations
First major publication on saturation in NEXUS/EPOS, 2006
Parton ladder splitting and the rapidity dependence of transverse momentum spectra in deuteron-gold collisions at the BNL Relativistic Heavy Ion Collider
K Werner, FM Liu, T Pierog
hep-ph/0506232 Published in Physical Review C 74 (4), 044902
Publication details and Citations
Theoretical basis of NEXUS/EPOS, 2001
Parton based Gribov-Regge theory
H.J. Drescher, M. Hladik, S. Ostapchenko, T. Pierog, K. Werner.
hep-ph/0007198 Published in Phys.Rept. 350 (2001) 93-289.
Publication details and Citations
The main VENUS publication, 1993
Strings, pomerons and the VENUS model of hadronic interactions at ultrarelativistic energies
K Werner
Physics Reports 232 (2-5), 87-299
Publication details and Citations