EPOS LHC: Test of collective hadronization with data measured at the CERN Large Hadron Collider

Abstract

EPOS is a Monte Carlo event generator for minimum bias hadronic interactions, used for both heavy ion interactions and cosmic ray air shower simulations. Since the last public release in 2009, the Large Hadron Collider (LHC) experiments have provided a number of very interesting data sets comprising minimum bias p-p, p-Pb, and Pb-Pb interactions. We describe the changes required to the model to reproduce in detail the new data available from the LHC and the consequences in the interpretation of these data. In particular we discuss the effect of the collective hadronization in p-p scattering. A different parametrization of flow has been introduced in the case of a small volume with high density of thermalized matter (core) reached in p-p compared to large volume produced in heavy ion collisions. Both parametrizations depend only on the geometry and the amount of secondary particles entering in the core and not on the beam mass or energy. The transition between the two flow regimes can be tested with p-Pb data. EPOS LHC is able to reproduce all minimum bias results for all particles with transverse momentum from p t = 0 to a few GeV/c.

Report of the Working Group on the Composition of Ultra High Energy Cosmic Rays

“…Ideally, this analysis should be performed with a combination of composition and hadronic interaction model that fits the Auger data well, such as Sibyll2.1 [8] or Epos-LHC [9] (see discussion in [4]). However, due to the lack of large air shower libraries other than QGSJetII-03 within the TA Collaboration, we performed the analysis with this model for practical reasons.…”

Air Shower Development and Hadron Production at Very Forward Region

“…Their water-Cherenkov type SD could count the number of muons in EAS, and was observed the surplus muon on the ground [12]. While the numbers of electro-magnetic component agreed with the prediction of the hadron interaction models, 33% more muons were detected than predicted by the EPOS-LHC [13] and 60% more were detected than predicted by the QGSJET II-04 [14].…”

Review of Model Predictions for Extensive Air Showers

“…Here we will focus on the three high energy models which were updated to take into account LHC data at 7 TeV: QGSJETII-03 [27,28] changed into QGSJETII-04 [29], EPOS 1.99 [30,31] replaced by EPOS LHC (v3400) [32], and Sibyll 2.1 [33][34][35] updated to Sibyll 2.3 [36] all available since COR-SIKA v7.5600 [37]. There is no major change in these models but in addition to some technical improvements, some parameters were changed to reproduce TOTEM [38] cross sections.…”