Influence of the hadronic phase on observables in ultrarelativistic heavy ion collisions

Steinheimer, Jan; Aichelin, Joerg; Bleicher, Marcus; Stöcker, H.

doi:10.1103/physrevc.95.064902

Cited by 44 publications

(32 citation statements)

References 46 publications

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“…Model calculations were performed for default parameters. Due to baryon annihilation in the hadronic phase, the pion, kaon and baryon yields cannot be simultaneously matched by assuming chemical equilibrium at one temperature [36][37][38][39][40][41][42]. First, the decoupling temperature was set to 140 MeV.…”

Section: Resultsmentioning

confidence: 99%

Evolution of charge fluctuations and correlations in the hydrodynamic stage of heavy ion collisions

Pratt

Kim

Plumberg³

2018

Phys. Rev. C

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Charge fluctuations for a baryon-neutral quark-gluon plasma have been calculated in lattice gauge theory. These fluctuations provide a well-posed rigorous representation of the quark chemistry of the vacuum for temperatures above T c 155 MeV. Due to the finite lifetime and spatial extent of the fireball created in relativistic heavy ion collisions, chargecharge correlations can only equilibrate for small volumes due to the finite time required to transport charge. This constraint leads to charge correlations at finite relative position that evolve with time. The source and evolution of such correlations is determined by the evolution of the charge fluctuation and the diffusion constant for light quarks. Here, calculations are presented for the evolution of such correlations superimposed onto hydrodynamic simulations. Results are similar to preliminary measurements from STAR, but significant discrepancies remain.

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Section: Resultsmentioning

confidence: 99%

Evolution of charge fluctuations and correlations in the hydrodynamic stage of heavy ion collisions

Pratt

Kim

Plumberg³

2018

Phys. Rev. C

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“…In this case the thermal picture should be extended to incorporate the hadronic phase, for instance using the concept of partial chemical equilibrium [55] or a hadronic afterburner. Both cases lead to suppressed yields of short-lived resonances relative to the chemical equilibrium statistical model predictions [56,57].…”

Section: Hadron Yield Ratiosmentioning

confidence: 90%

Canonical statistical model analysis of p−p , p -Pb, and Pb-Pb collisions at energies available at the CERN Large Hadron Collider

2019

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The system-size dependence of hadrochemistry at vanishing baryon density is considered within the canonical statistical model (CSM) with local exact conservation of three conserved charges, allowing for a possibility of strangeness undersaturation, i.e., γ S 1. Exact baryon number conservation is found to be even more important than that of strangeness in the canonical suppression picture at the CERN Large Hadron Collider, in contrast to intermediate and low collision energies. The model is applied to p-p, p-Pb, and Pb-Pb data of the ALICE Collaboration. A chemical equilibrium CSM with a fixed T ch = 155 MeV describes the trends seen in most yield ratios. However, this "vanilla" version of CSM predicts an enhancement of the φ/π ratio at smaller multiplicities, in stark contrast to the suppression seen in the data. The data are described with a 15% relative accuracy level whence a multiplicity dependence of both the temperature and the strangeness saturation parameter γ S 1 is accepted. Both the canonical suppression and the strangeness undersaturation effects are small at dN ch /dη 100, but they do improve substantially the description of hadron yields in p-p collisions, in particular the yields. A possibility to constrain the rapidity correlation volume using net-proton fluctuation measurements is pointed out.

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“…For instance, final absorption of the products of the resonance decays in the hadronic matter can substantially change the yields of the hadrons observed by the experimental detectors. This evolution of the hadronic matter can be successfully described by microscopic hadron cascade models [80][81][82].…”

Section: Micro-macro Hybrid Model Of Relativistic Heavy-ion Collisionsmentioning

confidence: 99%

Identifying the nature of the QCD transition in relativistic collision of heavy nuclei with deep learning

Zhou

Steinheimer

et al. 2020

Eur. Phys. J. C

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Using deep convolutional neural network (CNN), the nature of the QCD transition can be identified from the final-state pion spectra from hybrid model simulations of heavy-ion collisions that combines a viscous hydrodynamic model with a hadronic cascade "after-burner". Two different types of equations of state (EoS) of the medium are used in the hydrodynamic evolution. The resulting spectra in transverse momentum and azimuthal angle are used as the input data to train the neural network to distinguish different EoS. Different scenarios for the input data are studied and compared in a systematic way. A clear hierarchy is observed in the prediction accuracy when using the event-by-event, cascade-coarse-grained and event-fine-averaged spectra as input for the network, which are about 80%, 90% and 99%, respectively. A comparison with the prediction performance by deep neural network (DNN) with only the normalized pion transverse momentum spectra is also made. High-level features of pion spectra captured by a carefully-trained neural network were found to be able to distinguish the nature of the QCD transition even in a simulation scenario which is close to the experiments. trations of the usage of iEBE-VISHNU package and Volodymyr Vovchenko for helpful discussions. This work is supported by the Helmholtz Graduate School HIRe for FAIR (Y. D. and A. M.) , by the F&E Programme of GSI Helmholtz Zentrum für Schwerionenforschung GmbH, Darmstadt (Y. D.), by the Giersch Science Center (Y. D.), by the Walter Greiner Gesellschaft zur Förderung der physikalischen Grundlagenforschung e.V., Frankfurt (Y. D.), by the AI grant of SAMSON AG,

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Influence of the hadronic phase on observables in ultrarelativistic heavy ion collisions

Cited by 44 publications

References 46 publications

Evolution of charge fluctuations and correlations in the hydrodynamic stage of heavy ion collisions

Evolution of charge fluctuations and correlations in the hydrodynamic stage of heavy ion collisions

Canonical statistical model analysis of p−p , p -Pb, and Pb-Pb collisions at energies available at the CERN Large Hadron Collider

Identifying the nature of the QCD transition in relativistic collision of heavy nuclei with deep learning

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