Radiative and Collisional Jet Energy Loss in the Quark-Gluon Plasma at RHIC

TL;DR

This paper compares radiative and collisional energy loss mechanisms for jets in quark-gluon plasma at RHIC, highlighting their impact on jet quenching observables and matching theoretical predictions with experimental data.

Contribution

It provides a complete leading-order calculation of both energy loss processes, incorporating their probabilistic effects and applying them within a hydrodynamic medium model.

Findings

Nuclear modification factor $R_{AA}$ is sensitive to both energy loss mechanisms.

Including collisional energy loss slightly increases average energy loss at high energies.

Results align with experimental data on jet quenching at RHIC.

Abstract

We calculate and compare bremsstrahlung and collisional energy loss of hard partons traversing a quark-gluon plasma. Our treatment of both processes is complete at leading order in the coupling and accounts for the probabilistic nature of the jet energy loss. We find that the nuclear modification factor $R_{AA}$ for neutral $\pi^0$ production in heavy ion collisions is sensitive to the inclusion of collisional and radiative energy loss contributions while the averaged energy loss only slightly increases if collisional energy loss is included for parent parton energies $E\gg T$. These results are important for the understanding of jet quenching in Au+Au collisions at $200 {\rm AGeV}$ at RHIC. Comparison with data is performed applying the energy loss calculation to a relativistic ideal (3+1)-dimensional hydrodynamic description of the thermalized medium formed at RHIC.