Tomography of the Quark-Gluon-Plasma by Heavy Quarks

• Antragstellerin: Professorin Dr. Elena Bratkovskaya
• Fachliche Zuordnung: Kern- und Elementarteilchenphysik, Quantenmechanik, Relativitätstheorie, Felder
• Förderung: Förderung von 2013 bis 2016
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 230840978

The analysis of the experimental data from the heavy-ion accelerators at SPS, RHIC and LHC energies provide an indication for the creation of a new state of matter, a strongly interacting plasma of quarks and gluons (QGP). This new state lives for a very short period of time (~10 fm/c) before it is converted into hadrons which are finally observed in the detectors. The aim of this project is to study the properties of the QGP using heavy quarks -charm and beauty (c,b) - as nearly penetrating probes. The heavy quarks (and correspondingly charm and beauty mesons) are considered to be one of the best probes for such a study: i) due to their large mass they are produced dominantly by hard processes during the early stage of the reaction where the QCP is formed; ii) their initial momentum distribution can be calculated within perturbative Quantum Chromo Dynamics (pQCD); iii) while traversing the plasma they do not come into equilibrium with the environment since their interaction with the partons is not strong enough; iv) the final momentum of heavy mesons (D and B) is relatively independent of the detailed description of the hadronization process.To achieve this goal we embed the heavy quark physics in the existing microscopic PHSD (Parton-Hadron-String Dynamics) transport approach which incorporates explicit partonic degrees-of-freedom in terms of strongly interacting quasiparticles (quarks and gluons) in line with an equation-of-state from lattice QCD as well as the dynamical hadronization and hadronic collision dynamics in the final reaction phase. Since PHSD has been successfully applied to describe the final distribution of light mesons from lower SPS up to LHC energies, it provides therefore a solid framework for the description of the creation, expansion and hadronization of the QGP with which the heavy quarks interact. This proposal foresees to use first order next to leading log (FONLL) calculations to describe the creation of the heavy quarks. The transport approach will follow the trajectories of all heavy quarks; their interactions with the partons will be calculated applying pQCD. After hadronization charm (D) and beauty (B) mesons can interact with their hadronic environment before they finally arrive at the detector. A comparison of the available and upcoming experimental data with our approach will allow for a detailed study of the QGP properties. Especially the energy loss and the elliptic flow have been identified as sensitive probes of the QGP during the expansion. The embedding of charm and beauty quark dynamics in the PHSD approach will allow for comparing heavy quark and light quark observables and therefore for obtaining a comprehensive view of the reaction and the properties of the QGP.

• DFG-Verfahren: Sachbeihilfen