Speaker
Description
The jet transverse momentum diffusion coefficient $\hat{q}$ is an important transport coefficient governing the radiative energy loss of a parton propagating the Quark-Gluon Plasma (QGP) created in Heavy-Ion Collisions. Based on perturbative arguments [1], which were recently extended to next-to-leading order [2], the dimensionless ratio $\hat{q}/T^3$ was shown to be connected with the dimensionless specific shear viscosity $\eta/s$. This connection requires two assumptions: (a) that the medium is describable in terms of quasiparticle excitations, and (b) that the mean-free path of the parton is related to the average transport cross section of a quasiparticle in the medium implying that the interaction with the medium constituents is of the same form and strength as the interaction among the quasiparticles themselves.
Based on this idea, results of a microscopic calculation of $\hat{q}$ are presented by applying a quasiparticle model that was shown to provide a successful, effective description for the strongly coupled QGP [3]. This approach allows the determination of $\hat{q}$ in dependence of the identity of the traversing highly energetic parton and the composition of the hot strongly interacting matter. The behaviour of the jet quenching parameter as a function of temperature and parton momentum is discussed also in comparison with a recent Bayesian parameter estimation by the JETSCAPE Collaboration [4].
[1] A. Majumder, B. Müller and X. N. Wang, Phys. Rev. Lett. 99 (2007), 192301.
[2] B. Müller, Phys. Rev. D 104 (2021) no.7, L071501.
[3] V. Mykhaylova, M. Bluhm, K. Redlich and C. Sasaki, Phys. Rev. D 100 (2019) no.3, 034002.
[4] J. Mulligan et al. [JETSCAPE], arXiv:2106.11348 [nucl-th].
