The medium modification induced by jets in heavy ion collisions often manifests as an increase in medium particles in the direction of the parton (the so-called “wake”) and a decrease in the opposite direction (the so-called “diffusion wake”). In this talk, we will discuss jet-track correlations measured in photon-jet events from Pb+Pb collisions at 5.02 TeV with the ATLAS detector, in an...
Probing jet energy redistribution and broadening with hadron+jet correlations at ALICE and The search for jet scattering and medium response are merged to this talk
We begin by using Hybrid Model calculations to reproduce experimental results published by ATLAS in 2023 on $R_{AA}$ for $R=1$ jets in Pb+Pb collisions. These jets are identified via first reconstructing anti-$k_t$ $R=0.2$ subjets and then reclustering them. Following ATLAS, we investigate how $R_{AA}$ for these large-radius jets depends on the angle between the two subjets involved in the...
Due to the strongly coupled nature of quark-gluon plasma (QGP) formed in heavy-ion collisions, and the notorious difficulties in carrying out QCD calculations at realistic values of the coupling, supersymmetric N=4 Yang-Mills theory at large N_c has served as a highly helpful reference point to gain intuition on aspects of the strongly coupled physics of QGP.
In this work, we revisit the...
Heavy-ion collisions have been used to study quark-gluon plasma (QGP)
and can be used to study strong electromagnetic (EM) fields. Because the
EM fields penetrate the QGP medium, their evolutions are coupled
together. In turn, both contribute to the production of photons [1, 2].
Usually, the EM field modifications are considered separately from the
evolution of the QGP. Instead, we model...
Particles associated with the jet will be deflected from their initial direction due to the scatterings with the thermal partons flowing in the QGP fluid. Such deflections depend on the energy of the jet, the local energy gradient, and the local flow velocity. In general, the soft particles will drift towards the direction of the flowing medium, away from the center of the jet cone where the...
Jet-medium interaction not only leads to the energy loss of jet partons, but also induces medium excitations, such as the Mach cone generated by supersonic partons passing through the QGP. It is currently a hot topic to search for the decisive signal of jet-induced medium excitation in high-energy nuclear collisions. Here we present our recent work on searching for the signature of medium...
The jet-induced medium response of a quark-gluon plasma (QGP) is an intriguing phenomenon as it reveals dynamics of QGP at various wavelengths. However, it has not been unambiguously identified in experiments. This is mainly because of the complicated background of current observables. Furthermore, current observables only focus on consequences of the medium response in the momentum space. In...
Modification of jets is a powerful tool to diagnose a quark gluon plasma (QGP) in high-energy heavy-ion collisions. During propagation of partons in a jet through the QGP medium, constituents of the medium acquire high energy and momentum from them and are kicked out to be non-equilibrated partons. These partons are called the recoil partons. Together with how the jet partons radiate energy...
Over the last decades, the theoretical picture of how hadronic jets interact with nuclear matter has been extended to account for the medium’s finite longitudinal length and expansion. However, only recently a first-principle approach has been developed that allows to couple the jet evolution to the medium flow and anisotropic structure. In this talk, I will review these developments, and...
We introduce a sub-eikonal anisotropic contribution to jet-broadening, "jet drift", that couples to the flow of the nuclear medium, showing that this effect results in a deflection of hard partons, and thus jets, in the direction of the medium flow. Next, we study this effect in both toy models and a full-fledged hybrid transport simulation of √s = 5.02 TeV PbPb collisions at the LHC, tracking...
In hadronic collisions, heavy quarks are produced in hard scattering processes with large momentum transfer, which then generate a parton shower that develops into a jet. In heavy-ion collisions, where quark-gluon plasma (QGP) is produced, heavy quarks interact with the QGP constituents, losing energy which leads to quenching of the produced jets. In this process, the parton shower can be...
The physics of different angular scales can be separated using energy-energy correlators in pp collisions. The first energy-energy correlator measurement in PbPb collisions by the CMS experiment has recently observed this also in the heavy ion environment. Significant modifications in the shape of the correlator are observed in the large angle region, which corresponds to the free quark/gluon...
We study the energy deposition and thermalisation of high-momentum on-shell partons (minijets) travelling through a non-equilibrium Quark-Gluon Plasma using QCD kinetic theory. For thermal backgrounds, we show that the parton energy first flows to the soft sector by collinear cascade and then isotropises via elastic scatterings. In contrast, the momentum deposition from a minijet reaches the...
Collisions of small systems like pp and p+A remain one of the least understood scenarios of the heavy ion interactions. Limited ability to control the collisional geometry requires new observables, novel experimental approaches, and more sensitive analysis techniques. Such are available, in particular, by measuring heavy quarkonia states that offer an alternative classification scheme of...
In this work, we perform computations of inclusive jet and semi-inclusive jet-hadron cross sections for minimum-bias oxygen-oxygen collisions at RHIC and LHC collision energies. We compute the no-quenching baseline for the jet nuclear modification factor $R_\mathrm{AA}$ and jet-, and hadron-triggered semi-inclusive nuclear modification factors $I_\mathrm{AA}$. We do this with state-of-the-art...
We propose a novel approach to investigate the evolution of jets in heavy-ion collisions by employing a combination of jet substructure measurements. Our method focuses on isolating the perturbative regime of jet evolution. As a proof of concept, we analyze the distribution of the hardest splitting above a transverse momentum scale, $k_{t,{\rm cut}}$, in high-$p_T$ jets. For a $k_{t,{\rm...
Energy-Energy Correlators are a class of jet structure observables that has gained notoriety in recent years. These observables are designed and built from foundational concepts in field theory such as energy fluxes at varying resolution scales and are therefore a direct test of theoretical concepts with experimental measurements. With results from pretty much every experimental...
Energy correlators have been measured in heavy-ion collisions for the first time this year. We present a theoretical description and interpretation of the two-point energy correlator in the collinear limit of inclusive heavy-ion jet samples. Specifically, we focus on describing the effects of selection bias due to energy loss, which manifests as a shift in the transition region of the...
We investigate the flavor dependence of jet quenching, by performing a systematic analysis of medium modifications on the inclusive jet, $\gamma$+jet, and $b$-jet in Pb+Pb collisions at the LHC. Our results from MadGraph+PYTHIA exhibit excellent agreement with experimental measurements of the inclusive jet, $\gamma$+jet and $b$-jet simultaneously in p+p collisions. We then utilize a Bayesian...
We develop a linear Boltzmann transport model to describe the evolution of heavy and light flavor partons inside the QGP. By taking into account both elastic and inelastic scattering processes and both Yukawa (perturbative) and string (non-perturbative) interactions, we provide a good description of open heavy flavor hadron phenomenology from low to high transverse momenta. This model is then...
