Effects of jet-induced medium excitation in γ-hadron correlation in A+A collisions

Abstract

Coupled Linear Boltzmann Transport and hydrodynamics (CoLBT-hydro) is developed for cocurrent and event-by-event simulations of jet transport and jet-induced medium excitation (j.i.m.e.) in high-energy heavy-ion collisions. This is made possible by a GPU parallelized (3+1)D hydrodynamics that has a source term from the energy-momentum deposition by propagating jet shower partons and provides real time update of the bulk medium evolution for subsequent jet transport. Hadron spectra in γ-jet events of A+A collisions at RHIC and LHC are calculated for the first time that include hadrons from both the modified jet and j.i.m.e.. CoLBT-hydro describes well experimental data at RHIC on the suppression of leading hadrons due to parton energy loss. It also predicts the enhancement of soft hadrons from j.i.m.e. The onset of soft hadron enhancement occurs at a constant transverse momentum due to the thermal nature of soft hadrons from j.i.m.e. which also have a significantly broadened azimuthal distribution relative to the jet direction. Soft hadrons in the γ direction are, on the other hand, depleted due to a diffusion wake behind the jet.PACS numbers: 25.75.Bh,25.75.Cj,25.75.Ld

Interplaying mechanisms behind single inclusive jet suppression in heavy-ion collisions

“…Inelastic processes 2 → 2 + n with multiple gluon radiation and global energy-momentum conservation have also been implemented more consistently in the latest version [27,49,58]. It has been used to describe both single inclusive light and heavy flavor hadron suppression [50], γ-hadron [40], γ-jet [27,41,59] and Z 0 -jet correlations [60]. We will use it to study single inclusive jet suppression in high-energy heavy-ion collisions in this paper.…”

“…This linear approximation will break down when the jet-induced medium excitation becomes comparable to the local thermal parton density. To extend LBT beyond the linear approximation, a coupled LBT and hydrodynamic (CoLBT-hydro) model [40] has been developed in which soft partons from LBT jet transport are fed back to the bulk medium as a source term in the hydrodynamic equations while energetic partons propagate through the medium which evolve simultaneously with the source term updated in real time. This coupled approach is important for detailed study of the jet-induced medium excitation.…”

“…In the LBT model, a parton recombination model developed by the Texas A & M University group within the JET Collaboration [65] is used for hadronization of both jet shower and recoil medium partons. The model has been used successfully to describe light flavor hadron suppression in heavy-ion collisions [40]. In this paper, we will only use the partonic information for jet recon-struction and study single inclusive jet suppression and jet energy loss.…”

“…In heavy-ion collisions, however, the final jet production cross section is not only modified by parton energy loss of leading partons but also is influenced by how the lost energy is transported in the medium through radiated gluons and recoil medium partons. It is therefore imperative to include the effect of recoil partons and their further propagation in the form of jet-induced medium response as well as the propagation of radiated gluons in the study of jet suppression and medium modification [27,30,[35][36][37][38][39][40][41].…”

Medium response in JEWEL and its impact on jet shape observables in heavy ion collisions

“…In these calculations, soft partons that interacted with a jet, undergo further re-scattering and thereby thermalise [26][27][28]. Recently, hybrid approaches have been developed, that describe the propagation of jets in transport theory, but treat the thermal medium and its response to energy and momentum depositions by jets in hydrodynamics [15,17,29]. A different kind of hybrid approach is followed by [15], where the energy lost by a weak coupling jet is calculated at strong coupling and the medium response is again treated in hydrodynamics.…”