Speaker
Konrad Tywoniuk
(Universitat de Barcelona)
Description
Experimental evidence indicates that the quark-gluon plasma created in heavy-ion collisions at RHIC and LHC behaves like a strongly coupled liquid. These features are intimately related to the infrared (IR) behavior of QCD at finite temperature and present a challenge for conventional perturbative approaches. A way to tackle this obstacle is to improve the description of soft non-Abelian gauge degrees of freedom (DoF) using Gribov's quantization. In consequence, a physical scale, which at high temperature corresponds to the (chromo)magnetic scale, is induced in the system. We discuss how this novel framework affects the relevant quark collective DoF's. Strikingly, we uncover a previously unknown massless mode which is protected by a novel non-Abelian magnetic scaling. As a result, the quark spectral function violates positivity, a well-known feature of confinement. This sheds new light on the interplay of quasi-particle DoF's and genuine long-range modes in the deconfined pase of QCD. Within the same framework, we also discuss the impact of the modified IR dynamics on the jet quenching parameter. We calculate its temperature dependence and find a strong enhancement near the phase transition that is in line with the expectation of a strongly coupled QGP.
References:
N. Su and K. Tywoniuk, "Massless Mode and Positivity Violation in Hot QCD," PRL114, 161601 (2015) [arXiv:1409.3203 [hep-ph]];
Y. Guo, N. Su, K. Tywoniuk and Y. Zhu, "Jet quenching from antiscreening," (in preparation).
Author
Konrad Tywoniuk
(Universitat de Barcelona)
Co-authors
Nan Su
(Bielefeld University)
Yan Zhu
(Universidade de Santiago de Compostela (ES))
Yun Guo
(Guangxi Normal University, China)
