Systematic comparison of jet energy-loss schemes in a realistic hydrodynamic medium

Abstract

We perform a systematic comparison of three different jet energy-loss approaches. These include the Armesto-Salgado-Wiedemann scheme based on the approach of Baier-Dokshitzer-Mueller-Peigne-Schiff and Zakharov (BDMPS-Z/ASW), the higher twist (HT) approach and a scheme based on the Arnold-Moore-Yaffe (AMY) approach. In this comparison, an identical medium evolution will be utilized for all three approaches: this entails not only the use of the same realistic three-dimensional relativistic fluid dynamics (RFD) simulation, but also the use of identical initial parton-distribution functions and final fragmentation functions. We are, thus, in a unique position to not only isolate fundamental differences between the various approaches but also make rigorous calculations for different experimental measurements using state of the art components. All three approaches are reduced to versions containing only one free tunable parameter, this is then related to the well-known transport parameter $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{q}$. We find that the parameters of all three calculations can be adjusted to provide a good description of inclusive data on ${R}_{\mathit{AA}}$ vs transverse momentum. However, we do observe slight differences in their predictions for the centrality and azimuthal angular dependence of ${R}_{\mathit{AA}}$ vs ${p}_{T}$. We also note that the values of the transport coefficient $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{q}$ in the three approaches to describe the data differ significantly.