STRINTQGP · Strong interactions in the quark-gluon plasma
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2005-12-01 → 2007-11-30
- EU contribution
- €150,260
- Participants
- 1
- Scheme
- EIF
Lines connect the coordinator with its partners.
Results in brief
Final Activity Report Summary - STRINTQGP (Strong interactions in the quark-gluon plasma)
Exploration of the hadronic matter and the quark-gluon plasma, together with deconfinement transition between these two phases, is one of the great challenges in modern physics. The deconfinement phase transition is the only one in the early Universe, which can be studied experimentally, by colliding nuclei at ultra-relativistic energies. Experiments at the 'Relativistic heavy ion collider' (RHIC) at Brookhaven, performed at such energies, have led to numerous discoveries. Altogether, they evidence that the quark-gluon plasma is strongly coupled even at temperatures as large as few times the deconfinement critical temperature in QCD. Numerical simulations of finite-temperature QCD on the lattice complement the heavy-ion experimental program. They provide a lot of new information on the nonperturbative properties of QCD in both the hadronic and the quark-gluon plasma phases. The main objective for this project was the analysis of nonperturbative thermodynamics and kinetics of the quark-gluon plasma, as those are described by the RHIC experiments and lattice simulations. The project can be charecterised by the following keywords: quantum chromodynamics (QCD), quark-gluon plasma, heavy-ion collisions, confinement-deconfinement phase transition, static quark-antiquark potential, QCD string-breaking in the hadronic phase, Debye screening in the quark-gluon plasma phase, chromo-magnetic gluon condensate and spatial confinement, valence gluons, QCD running coupling, event-shape variables in QCD, QCD jets, radiative energy loss and jet quenching. Specifically, the main results were obtained in the following four directions: 1. Description of the recent lattice data on the thermodynamics of a static quark-antiquark pair at separations larger than 1.5 fermi, in the vicinity of the deconfinement phase transition. 2. The analysis of the so-called infra-red freezing (i.e. finiteness) of the running strong coupling, in the confinement and deconfinement phases of QCD. 3. Analysis of the energy loss of a parton traversing the quark-gluon plasma, which it experiences through the interactions with hard thermal gluons. 4. Studies of the degree to which the quark-gluon plasma deviates from ideality. These results are fundamentally important for the calculation of various kinetic coefficients of the quark-gluon plasma, such as the bulk viscosity.
Data: CORDIS, © European Union
Project objective
The primary goal of the project is to study strong interactions in the quark-gluon plasma by using the finite-temperature generalizations of the loop-loop correlation model, as well as of the stochastic vacuum model, it is based on. Specifically, it is planned to study scattering cross sections of various bound states of quasi-particles with the effects of magnetic confinement implemented. It is expected that the so-enlarged cross sections will lead to a significant reduction of the viscosity of the plasma, bringing its theoretical values to an agreement with the present experimental ones. As one of the necessary ingredients for this calculation one should have an accurate finite-temperature expression for the running strong coupling in the infrared region. To this end, it is planned to elaborate some non-perturbative techniques, which will allow to account for the effects of confinement in various QCD amplitudes (that, even at zero temperature, will be important of its own). Furthermore, on the basis of the stochastic vacuum model, it is planned to develop a theory of QCD-string breaking. Such a theory will be more general than the recently suggested one, which relies on the Schwinger's mechanism for the pair creation in the field of a string. By using both theories, the detailed studies of the spectra of quasiparticle bound states, as well as of the dissociation temperatures of these states, will be performed. It is also planned to derive the one-loop effective potential for gluons in the stochastic background and to study the phenomenological equation of state in the quark-gluon plasma, which would respect the approximate Casimir scaling for k-string tensions, confirmed both analytically and on the lattice.
Original text from CORDIS.
Participants
- RUPRECHT-KARLS-UNIVERSITAET HEIDELBERG · HEIDELBERGCoordinatorGermany
Links
Data: CORDIS, © European Union