Title: Traces of nonequilibrium effects, initial condition, bulk dynamics, and elementary collisions in the charm observables

Abstract

Heavy quarks produced in relativistic heavy-ion collisions are known to be sensitive probes of the hot and dense QCD matter they traverse. In this paper we study how their dynamics is affected by the nature of the bulk evolution of the QCD matter, the initial condition of the system, and the treatment of elementary interactions between heavy quarks and the surrounding medium. For the same initial condition and the same quark-gluon plasma (QGP) expansion scenario we discuss the consequences of the assumption of a local equilibrium by comparing the consequences for the nuclear modification factor $$R_{AA}$$ and the elliptic flows of charm quarks, scrutinizing the different components of the final distribution of charm quarks. For this purpose we employ the parton-hadron-string dynamics (PHSD) model, which is an off-shell microscopic transport approach, as well as the linearized-Boltzmann (LB) scheme obtained by coarse graining the PHSD bulk and assuming local equilibrium for the interactions of the charm quarks with the bulk. The $$R_{AA}$$ of charm quarks stemming from the later LB approach is also compared to a genuine fluid dynamics evolution initiated by the coarse grained PHSD, which allows us to further assess the consequences of reducing the full $$\textit{n}$$-body dynamics. We then proceed to a systematic comparison of PHSD (in its LB approximation) with MC@HQ, another transport model for heavy flavors which also relies on the LB approach. In particular, we investigate the consequences for the nuclear modification factor of charm quarks if we vary separately the initial heavy quark distribution function in matter, the expansion dynamics of the QGP, and the elementary interactions of heavy quarks of these models. We find that the results for both models vary significantly depending on the details of the calculation. However, both models achieve very similar predictions for key heavy quark observables for certain combinations of initial condition, bulk evolution, and interactions. In this work, we conclude that this ambiguity limits our ability to determine the different properties of the system based on the current set of observables.

Authors:

Song, Taesoo  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-5321-7869"

Moreau, Pierre ^[2]; Xu, Yingru ^[3]; Ozvenchuk, Vitalii  ^[4];

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• Search DOE PAGES for ORCID "0000-0002-7821-7109"

Bratkovskaya, Elena ^[5]; Aichelin, Joerg ^[6]; Bass, Steffen A.  ^[3];

• Search DOE PAGES for author "Bass, Steffen A."
• Search DOE PAGES for ORCID "0000-0002-9451-0954"

Gossiaux, Pol Bernard ^[7]; Nahrgang, Marlene ^[7]

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+ Show Author Affiliations

1. GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany)
2. Duke Univ., Durham, NC (United States); Johann Wolfgang Goethe Universität, Frankfurt (Germany)
3. Duke Univ., Durham, NC (United States)
4. Polish Academy of Sciences (PAS), Krakow (Poland); SUBATECH UMR 6457, Nantes (France); IMT Atlantique (France); Université de Nantes (France); Centre National de la Recherche Scientifique (CNRS) (France). National Institute of Nuclear Physics and Particle Physics
5. GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Johann Wolfgang Goethe Universität, Frankfurt (Germany)
6. SUBATECH UMR 6457, Nantes (France); IMT Atlantique (France); Université de Nantes (France); Centre National de la Recherche Scientifique (CNRS) (France). National Institute of Nuclear Physics and Particle Physics; Frankfurt Institute for Advanced Studies (FIAS) (Germany)
7. SUBATECH UMR 6457, Nantes (France); IMT Atlantique (France); Université de Nantes (France); Centre National de la Recherche Scientifique (CNRS) (France). National Institute of Nuclear Physics and Particle Physics

Publication Date:

Wed Apr 22 00:00:00 EDT 2020

Research Org.:

Duke Univ., Durham, NC (United States)

Sponsoring Org.:

USDOE Office of Science (SC); German Academic Exchange Service (DAAD); National Science Centre of Poland (NCN); German Research Foundation (DFG); European Union’s Horizon 2020; Region Pays de la Loire

OSTI Identifier:

1800265

Alternate Identifier(s):

OSTI ID: 1615709

Grant/Contract Number:  

FG02-05ER41367; 2014/14/E/ST2/00018; CRC-TR 211; 824093; 2015-08473

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review C

Additional Journal Information:

Journal Volume: 101; Journal Issue: 4; Journal ID: ISSN 2469-9985

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

73 NUCLEAR PHYSICS AND RADIATION PHYSICS; Physics