Linear Boltzmann transport for jet propagation in the quark-gluon plasma: Elastic processes and medium recoil

Abstract

A Linear Boltzmann Transport model within perturbative QCD is developed for the study of parton propagation inside the quark-gluon plasma. Both leading partons and thermal recoil partons are tracked so that one can also study jet-induced medium excitations. In this study, we implement the complete set of elastic parton scattering processes and investigate elastic parton energy loss, transverse momentum broadening and their nontrivial energy and length dependence. We further investigate medium modifications of the jet shape and fragmentation functions of reconstructed jets. Contributions from thermal recoil partons are found to have significant influences on jet shape, fragmentation functions and angular distribution of reconstructed jets.

Groomed jets in heavy-ion collisions: sensitivity to medium-induced bremsstrahlung

“…In contrast to the former, it is currently a subject of theoretical debate and various implementations exist, see, e.g. [55][56][57][58].…”

“…(4.4) since there is only one component. Monte Carlo event generators that include medium recoil effects, such as [55][56][57][58], should be sensitive to this modification.…”

Angular structure of jet quenching within a hybrid strong/weak coupling model

“…Something similar can happen at weak coupling even though the energy is initially lost by gluon radiation because these radiated gluons can experience a cascade of reinteractions that converts the energy into soft particles at large angles [150][151][152][153][154][155][156]. The effects of both transverse momentum broadening [85,86,[107][108][109] and the backreaction of the medium [95,[157][158][159][160][161][162] on jet observables have also been studied within the context of perturbative energy loss mechanisms.…”

“…It is inevitable that when a jet reconstruction algorithm is used to find and reconstruct jets in heavy ion collisions, some of the energy and momentum that is counted as part of a jet in fact comes from hadrons formed from the plasma as it freezes out, given that the plasma includes a moving heated wake that, by momentum conservation, is flowing in the same direction as the jet [95,158,[160][161][162]. Furthermore, since any background subtraction procedure involves comparing events with a jet or jets to events that do not contain jets, and since events that do not contain jets also do not contain wakes, the particles from the hadronization of the wake that end up reconstructed as part of a jet will not be removed by background subtraction.…”

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

“…While these approaches rely on a clear separation between jet and medium degrees of freedom, transport codes treat all partons, whether they are hard or soft, on equal footing. 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].…”