Speaker
Description
In this talk, we will discuss how high-pt data can be used to constrain tau0, the onset time of energy loss and fluid-dynamical evolution, an important parameter of our description the evolution of QGP created in relativistic heavy-ion collisions. We first consider a scenario without pre-equilibrium evolution, and demonstrate that high-pt data clearly prefers later tau0. Then, we consider several more sophisticated scenarios with pre-equilibrium evolution and show that high-pt RAA and v2 are sensitive to different initializations and early expansion dynamics and that they prefer later onset of energy loss and transverse expansion.
Moreover, we consider the spatial anisotropy of the QGP, as it is one of the main properties of this system. We propose a novel method to extract the spatial anisotropy from high pt data. Based on numerical calculations and comparisons with experimental data, we show that a modified ratio of v2 and RAA reaches a well-defined saturation value, which is directly proportional to the time-averaged anisotropy of the evolving QGP. We relate this ratio to a new observable, which we call jet-perceived anisotropy, and we argue that it can provide constraints on bulk-medium simulations.
