Event-by-event jet anisotropy and hard-soft tomography of the quark-gluon plasma

TL;DR

This paper investigates jet anisotropy in quark-gluon plasma using a comprehensive event-by-event simulation framework, revealing how jet quenching and medium flow influence jet azimuthal anisotropy in heavy-ion collisions.

Contribution

It introduces a detailed event-by-event modeling approach combining LBT and hydrodynamics to study jet anisotropy and its correlation with soft hadron flow in heavy-ion collisions.

Findings

Jet elliptic ($v_2^{ m jet}$) and triangular ($v_3^{ m jet}$) anisotropies are calculated.

A linear correlation between jet $v_2$ and bulk flow $v_2$ is observed.

Bulk flow fluctuations have negligible effect on jet anisotropy.

Abstract

Suppression of jet spectra or jet quenching in high-energy heavy-ion collisions is caused by jet energy loss in the dense medium. The azimuthal anisotropy of jet energy loss in non-central heavy-ion collisions can lead to jet anisotropy which in turn can provide insight into the path-length dependence of jet quenching. This is investigated within the Linear Boltzmann Transport (LBT) model which simulates both elastic scattering and medium-induced gluon radiation based on perturbative QCD for jet shower and medium recoil partons as well as radiated gluons as they propagate through the quark-gluon plasma (QGP). The dynamical evolution of the QGP in each event of heavy-ion collisions is provided by the (3+1)D CLVisc hydrodynamic model with fully fluctuating initial conditions. This framework has been shown to describe the suppression of single inclusive jet spectra well. We calculate in this study the elliptic ($v_{2}^{\rm jet}$) and triangular ($v_{3}^{\rm jet}$) anisotropy coefficients of the single inclusive jet spectra in Pb+Pb collisions at the LHC energies. We investigate the colliding energy, centrality, jet transverse momentum dependence of the jet anisotropy, as well as their event-by-event correlation with the flow coefficients of the soft bulk hadrons. An approximate linear correlation between jet and bulk $v_2$ is found. Effect of the bulk $v_n$ fluctuation on $v_n^{\rm jet}$ is found negligible. The jet-induced medium excitation, which is influenced by radial flow, is shown to enhance $v_{2}^{\rm jet}$ and the enhancement increases with the jet cone size. The jet elliptic anisotropy $v_{2}^{\rm jet}$ is also found to be slightly enhanced by the shear viscosity of the bulk medium in comparison to the LBT results when jets propagate through an ideal hydrodynamic QGP medium.