[a]Carlota Andres

# Jet medium modifications

###### Abstract

Since the start of the heavy-ion collision programs at the Relativistic Heavy
Ion Collider and the Large Hadron Collider, the study of jet modifications
resulting from their interactions with the produced QCD matter has provided a
unique tool to investigate and characterize the properties of the quark-gluon
plasma. In this mini-overview, I will present the recent theoretical
advancements in describing and understanding the modifications of jets within
a QCD medium.

##  1 Introduction

In high-energy nuclear collisions, the occasional occurrence of a hard
scattering between the incoming partons leads to the production of highly
virtual partons. These high-energy partons then traverse all the stages of the
system’s evolution, including the quark-gluon plasma (QGP) phase, eventually
fragmenting into collimated sprays of hadrons known as jets. The interactions
between heavy-ion jets and the QCD matter generated in these collisions give
rise to distinct modifications compared to proton-proton jets. This
phenomenon, widely known as jet quenching, has become a crucial avenue for
studying the QGP.

##  2 Energy loss

Jet quenching was first established at the Relativistic Heavy Ion Collider
(RHIC) in the context of single-inclusive hadron spectra and high-$p_{T}$
hadron correlations, with the observed suppression indicating the energy loss
experienced by the leading particle as it traverses the QGP [1]. In typical
events, the leading parton is either a light quark or a gluon, and its energy
loss is primarily driven by its frequent soft interactions with the medium
which generate collinear (medium-induced) radiation. Consequently, the early
emphasis within the jet quenching community was on computing the spectrum of
medium-induced radiation and its applications to energy loss observables.

A complete description of a medium-induced gluon emission off a highly
energetic parton requires the resummation of multiple scatterings, given the
important role played by interference effects among scatterings resulting into
the well known Landau-Pomeranchuk-Migdal (LPM) effect. This resummation can be
formally performed within the BDMPS-Z framework [2, 3]. To successfully
incorporate all multiple scatterings into the well-known BDMPS-Z compact
formula, several assumptions are made. Firstly, it is assumed that the opening
angle of the radiation is small, and the emission vertices are described by
leading-order DGLAP splitting functions. Secondly, the interactions between
the parton and the medium are considered instantaneous and mediated by soft
gluons, which only transfer transverse momenta to the probe. In addition, a
common simplifying assumption is to treat the radiated gluon as soft, allowing
for its interpretation as energy loss of the emitter. This assumption is
typically expressed as $\omega\equiv zE\ll E$, where $\omega$ and $E$
represent the energies of the radiated gluon and the initial parton,
respectively. By considering this limit, the calculation is simplified, and
the dominant contribution to the spectrum is obtained due to the soft
divergence of the DGLAP splitting functions for gluon radiation. It is
important to note that while implementing this soft limit is not strictly
required for the derivation of the BDMPS-Z spectrum, its relaxation while
still retaining information on the emission angle $\theta$ has proven to be
challenging [4, 5].

Historically, the evaluation of the BDMPS-Z formula has been limited to a few
specific scenarios. One approach involves truncating the resummation series at
first order in an opacity expansion [6], while another method resumes all
multiple scatterings but under the assumption that the transverse momentum
transfers follow a Gaussian profile (known as the harmonic oscillator
approximation). The determination of the spectrum also simplifies for an
infinite static medium [7]. In recent years, significant efforts have been
dedicated to systematically improving our understanding of medium-induced
emissions. Both analytical and numerical advancements have enabled the
evaluation of the BDMPS-Z spectrum beyond these simplified scenarios [8, 9,
10, 11, 12, 13, 14], allowing us to quantify their kinematic ranges of
validity for an idealized static QGP [15]. This progress is illustrated in
figure 1, where the first opacity result approximates the high energy tail of
the spectrum well, but tends to overestimate it at lower gluon energies due to
the absence of interferences among scatterings. These evaluations were
agnostic to the specifics of the collision rate or parton-medium interaction
model entering the spectrum expression, provided it exhibits the expected
Coulomb-like screening behavior for large transverse momentum transfers.
Notably, recent studies [16] have revealed that incorporating a collision rate
with proper matching to the infrared sector [17] has a large impact on the
spectrum.

Figure 1: Full medium-induced gluon spectrum from [12] (magenta solid line)
compared to the harmonic oscillator+NLO approximation from [10, 11] (green
dashed), first opacity result (blue dash-dotted) [6], and the low energy limit
of the full resummation described in section 4 of [15] (black dotted) as a
function of $\omega$ rescaled by the energy scale $\omega_{\mathrm{BH}}$.
Figure taken from [15], to which we refer the reader for details.

While these advancements have significantly deepened our understanding of the
in-medium emission process, their implications on jet quenching
phenomenological analyses are yet to be fully explored. In fact, for some
energy loss observables, the differences among various approaches might
potentially be absorbed into the fitted values of free parameters [18],
typically the jet transport coefficient $\hat{q}$ or the strong coupling
$\alpha_{s}$, depending on the formalism. This is illustrated in figure 2,
where we observe that for the $0-5\%$ centrality class in $\sqrt{s_{\rm
NN}}=2.76$ TeV Pb-Pb collisions, the curves representing different collision
kernel models collapse onto each other and become indistinguishable when the
strong coupling value is separately fitted to the charged hadron $R_{\rm AA}$
data for each of them. This outcome is not entirely surprising, as the $R_{\rm
AA}$ dependence on $p_{T}$ is primarily governed by the steeply decreasing
(with $p_{T}$) hard hadron production spectrum. Therefore, it would be highly
desirable to analyze the impact of these developments on the theory of medium-
induced radiation on other more differential observables.

Figure 2: Charged hadron $R_{\rm AA}$ as a function of $p_{T}$ computed using
MARTINI [19] with AMY (infinite length) rates [7] using either a LO (orange)
collision rate, a NLO collision rate (blue), or a collision rate matched to
the infrared Lattice result in [17] (red). The left panel uses
$\alpha_{s}=0.3$ for the three curves, while the right panel uses fitted
values of $\alpha_{s}$, yielding: $\alpha_{s}=0.28$ (orange),
$\alpha_{s}=0.24$ (blue), and $\alpha_{s}=0.26$ (red). Figure taken from [18],
to which we refer the reader for further details.

Furthermore, recent endeavors have focused on investigating the impact of the
transverse flow or transverse inhomogeneities within the QGP on medium-induced
radiation and broadening. To address these aspects, it becomes necessary to
generalize the original BDMPS-Z formalism, since in the high-energy
(_eikonal_) limit for the emitter in which it was derived the longitudinal and
transverse degrees of freedom are completely decoupled. The relaxation of the
eikonal limit allows to compute corrections due to transverse flow and/or
transverse density gradients which are proportional to inverse powers of the
energy of the emitted gluon [20, 21, 22, 23, 24]. These _sub-eikonal_
transverse corrections are expected to cause the jets to drift in the
direction of the transverse flow or temperature gradient, resulting in an
asymmetry in their transverse distribution [25, 26].

##  3 From energy loss to jet substructure

Recent years have witnessed remarkable progress in the measurement of
increasingly differential jet observables in heavy-ion collisions, see e.g.
[27] for a comprehensive review. Of particular interest is the study of
modifications to the inner structure of heavy-ion jets, as it provides
insights into the dynamics of the QGP at its different stages, which is
reflected in the various scales of the substructure of the jet. However, the
theoretical interpretation of jet substructure observables remains challenging
due to the interplay of multiple phenomena, including color coherence [28] and
medium response [29] effects.

Medium-induced emissions, when radiated at small angles, can also modify the
inner structure of jets, making the precise description of in-medium emissions
crucial for fully exploiting jet substructure observables as probes of the
QGP. A key aspect in this regard is to accomplish the complete calculation of
medium-induced splittings, taking into account the differential dependence on
both the relative angle $\theta$ and the fraction of longitudinal momentum $z$
carried by the emitted parton, beyond the soft limit in which $z\rightarrow
0$. To tackle this issue, two available approaches have been considered:
performing an expansion in opacity or resumming all scatterings using a _semi-
hard_ approximation. At first order in opacity, the double-differential
spectrum beyond the soft limit, i.e for finite (non-zero) $z$, is well known
[30]. Recursive formulas have been derived for higher-order opacity terms,
enabling the numerical evaluation at second order [31, 32]. However, it is
important to note that truncating the in-medium splitting in opacity leads to
unitarity issues, which results in negative cross sections. Alternatively, the
_semi-hard_ approximation within the BDMPS-Z framework assumes that all
partons propagate along straight-line trajectories while undergoing color
rotations [33, 34]. While this simplification enables the calculation of the
double-differential spectrum with resummation of all multiple scatterings for
finite $z$, it neglects certain broadening effects. These two approximations
of the double-differential spectra have been employed, for instance, to
compute the two-point energy correlator of a heavy-ion jet [35, 36], which is
a novel and promising substructure observable in heavy-ion physics. Notably,
the first-ever preliminary measurements of this observable in p-p jets were
presented by the STAR and ALICE collaborations at this conference [37, 38],
showing a clear (and expected) angular separation between its non-perturbative
and perturbative regimes [39].

Recently, a significant development has been the computation of the double-
differential spectrum incorporating the resummation of multiple scatterings
for finite $z$, without relying on the semi-hard approximation, for specific
splittings. One of these cases is the in-medium $g\rightarrow c\bar{c}$
splitting, which was obtained in the large number of colors (large-$N_{c}$)
limit within the harmonic oscillator approximation [40], revealing an
enhancement of the number of $c\bar{c}$ pairs in heavy-ion jets compared to
p-p jets. Notably, the computation of this particular splitting at large
$N_{c}$ is slightly less complicated compared to other $1\rightarrow 2$
splittings, as it does not involve the calculation of 4-point correlators of
Wilson lines (quadrupole). The other case is the $\gamma\rightarrow q\bar{q}$
splitting obtained in [41], which already involves the calculation of the
quadrupole at large $N_{c}$. In this large-$N_{c}$ limit and under the
harmonic oscillator approximation, the quadrupole can be analytically
obtained. More interestingly, the authors in [41] have developed a numerical
method based on solving a system of coupled Schrödinger equations, which
allows for the calculation of the quadrupole for finite numbers of colors.
This recipe could potentially be applied to the $q\rightarrow qg$ and
$g\rightarrow gg$ processes as well, providing an opportunity to evaluate the
accuracy of the commonly used approximations to obtain the double-differential
spectrum for these emissions, including the _semi-hard_ approximation. It is
worth noting, however, that the computational complexity of the approach in
[41] would considerably increase for these particular splittings.

Up to this point, our discussion has focused on single in-medium gluon
emissions. However, over the past years there has been an ongoing effort to
determine the in-medium double-gluonic splitting ($g\rightarrow ggg$), see
[42, 43] and references therein. The ultimate goal of these calculations is to
determine whether in-medium showers can be treated as a sequence of
independent $1\rightarrow 2$ splittings or if there is a significant quantum
overlap between successive splittings. These developments suggest, albeit with
some caveats, that for gluonic cascades the overlapping effects among multiple
splittings are expected to be small [43]. This finding implies that the
assumed Markovian nature of in-medium showers is not significantly challenged.

##  4 The role of the initial stages on jet quenching phenomena

Given that jets originate from hard partons produced in the hard process
occurring in the initial collision, they witness the full space-time evolution
of the produced QCD matter, including the _initial stages_. However, most of
jet quenching phenomenological studies typically neglect any quenching effects
prior to the hydrodynamization phase. Recent studies have shown that certain
energy loss observables are indeed sensitive to these early stages [44, 45,
46]. Nevertheless a comprehensive understanding of the impact of these initial
stages on jet quenching observables in heavy-ion collisions is still lacking.
Importantly, understanding jet quenching in the early stages becomes crucial
to interpret the apparent lack of energy loss in small collisions systems (p-A
and high multiplicity p-p), where these initial stages constitute a
significantly larger fraction of the overall system’s evolution compared to
A-A collisions.

In the last few years, there has been a growing effort to compute the momentum
broadening of both jets and heavy quarks during the early stages of heavy-ion
collisions [47, 48, 49, 50, 51, 52, 53, 54]. These advancements encompass the
glasma phase [47, 48, 49, 50, 51], which occurs shortly after the initial
collision and is characterized by highly occupied classical gluonic fields, as
well as the kinetic theory stage [52, 53, 54] where the system is described as
an interacting gas composed of gluon and quark quasiparticles. These
calculations revealed that the jet quenching parameter $\hat{q}$ in these pre-
hydrodynamization stages is relatively large, comparable to or even larger
than in the QGP phase, suggesting that these early stages might have a
significant effect on jet quenching phenomena. Moreover, both in the glasma
and kinetic phases $\hat{q}$ has been found to be anisotropic, with a larger
magnitude along the beam direction. This anisotropy would lead to the
polarization of in-medium emissions from initially unpolarized emitters.
However, the polarization may be washed out by subsequent branchings making it
uncertain whether a net jet’s polarization may survive the QGP phase [55].

##  5 Conclusions

In recent years, there have been significant advancements in the theoretical
description of the modifications experienced by jets and high-$p_{T}$ hadrons
in heavy-ion collisions with respect to p-p collisions. These developments
have the potential of serving as valuable benchmark for current jet quenching
Monte Carlo (MC) approaches. While jet quenching MC simulations are highly
useful, they currently rely on various modeling assumptions and approximations
that may obscure the interpretation of the underlying physical phenomena (see
e.g. [56]). The ongoing progress based on first-principles QCD calculations
summarized in this overview may provide an opportunity to guide and test
future MC developments.

##  6 Acknowledgements

I would like to express my gratitude to the Hard Probes 2023 Organizing
Committee for the invitation to present an overview on the medium modification
of jets in heavy-ion collisions. C.A. has received funding from the European
Union’s Horizon 2020 research and innovation program under the Marie
Sklodowska-Curie grant agreement No 893021 (JQ4LHC). This work was supported
by OE Portugal, Fundação para a Ciência e a Tecnologia (FCT), I.P., projects
EXPL/FIS-PAR/0905/2021.

## References

  * [1] J. Adams et al. [STAR], _Evidence from d + Au measurements for final state suppression of high p(T) hadrons in Au+Au collisions at RHIC,_ Phys. Rev. Lett. 91, 072304 (2003) [arXiv:nucl-ex/0306024 [nucl-ex]].
  * [2] R. Baier, Y. L. Dokshitzer, A. H. Mueller, S. Peigne and D. Schiff, _Radiative energy loss of high-energy quarks and gluons in a finite volume quark - gluon plasma,_ Nucl. Phys. B 483, 291-320 (1997) [arXiv:hep-ph/9607355 [hep-ph]].
  * [3] B. G. Zakharov, _Fully quantum treatment of the Landau-Pomeranchuk-Migdal effect in QED and QCD,_ JETP Lett. 63, 952-957 (1996) [arXiv:hep-ph/9607440 [hep-ph]].
  * [4] J. P. Blaizot, F. Dominguez, E. Iancu and Y. Mehtar-Tani, _Medium-induced gluon branching,_ JHEP 01, 143 (2013) [arXiv:1209.4585 [hep-ph]].
  * [5] L. Apolinário, N. Armesto, J. G. Milhano and C. A. Salgado, _Medium-induced gluon radiation and colour decoherence beyond the soft approximation,_ JHEP 02, 119 (2015) [arXiv:1407.0599 [hep-ph]].
  * [6] M. Gyulassy, P. Levai and I. Vitev, _Jet quenching in thin quark gluon plasmas. 1. Formalism,_ Nucl. Phys. B 571, 197-233 (2000) [arXiv:hep-ph/9907461 [hep-ph]].
  * [7] P. B. Arnold, G. D. Moore and L. G. Yaffe, _Photon and gluon emission in relativistic plasmas,_ JHEP 06, 030 (2002) [arXiv:hep-ph/0204343 [hep-ph]].
  * [8] S. Caron-Huot and C. Gale, _Finite-size effects on the radiative energy loss of a fast parton in hot and dense strongly interacting matter,_ Phys. Rev. C 82, 064902 (2010) [arXiv:1006.2379 [hep-ph]].
  * [9] X. Feal and R. Vazquez, _Intensity of gluon bremsstrahlung in a finite plasma,_ Phys. Rev. D 98, no.7, 074029 (2018) [arXiv:1811.01591 [hep-ph]].
  * [10] Y. Mehtar-Tani, _Gluon bremsstrahlung in finite media beyond multiple soft scattering approximation,_ JHEP 07, 057 (2019) [arXiv:1903.00506 [hep-ph]].
  * [11] J. Barata and Y. Mehtar-Tani, _Improved opacity expansion at NNLO for medium induced gluon radiation,_ JHEP 10, 176 (2020) [arXiv:2004.02323 [hep-ph]].
  * [12] C. Andres, L. Apolinário and F. Dominguez, _Medium-induced gluon radiation with full resummation of multiple scatterings for realistic parton-medium interactions,_ JHEP 07, 114 (2020) [arXiv:2002.01517 [hep-ph]].
  * [13] C. Andres, L. Apolinário, F. Dominguez and M. G. Martinez, _In-medium gluon radiation spectrum with all-order resummation of multiple scatterings in longitudinally evolving media,_ [arXiv:2307.06226 [hep-ph]].
  * [14] S. Stojku, B. Ilic, I. Salom and M. Djordjevic, _Importance of higher orders in opacity in QGP tomography,_ [arXiv:2303.14527 [nucl-th]].
  * [15] C. Andres, F. Dominguez and M. Gonzalez Martinez, _From soft to hard radiation: the role of multiple scatterings in medium-induced gluon emissions,_ JHEP 03 (2021), 102 [arXiv:2011.06522 [hep-ph]].
  * [16] S. Schlichting and I. Soudi, _Splitting rates in QCD plasmas from a nonperturbative determination of the momentum broadening kernel C(q $\perp$),_ Phys. Rev. D 105, no.7, 076002 (2022) [arXiv:2111.13731 [hep-ph]].
  * [17] G. D. Moore and N. Schlusser, _Transverse momentum broadening from the lattice,_ Phys. Rev. D 101, no.1, 014505 (2020) [erratum: Phys. Rev. D 101, no.5, 059903 (2020)] [arXiv:1911.13127 [hep-lat]].
  * [18] R. M. Yazdi, S. Shi, C. Gale and S. Jeon, _Leading order, next-to-leading order, and nonperturbative parton collision kernels: Effects in static and evolving media,_ Phys. Rev. C 106, no.6, 064902 (2022) [arXiv:2206.05855 [hep-ph]].
  * [19] B. Schenke, C. Gale and S. Jeon, _MARTINI: An Event generator for relativistic heavy-ion collisions,_ Phys. Rev. C 80, 054913 (2009) [arXiv:0909.2037 [hep-ph]].
  * [20] A. V. Sadofyev, M. D. Sievert and I. Vitev, _Ab initio coupling of jets to collective flow in the opacity expansion approach,_ Phys. Rev. D 104, no.9, 094044 (2021) [arXiv:2104.09513 [hep-ph]].
  * [21] J. Barata, A. V. Sadofyev and C. A. Salgado, _Jet broadening in dense inhomogeneous matter,_ Phys. Rev. D 105, no.11, 114010 (2022) [arXiv:2202.08847 [hep-ph]].
  * [22] C. Andres, F. Dominguez, A. V. Sadofyev and C. A. Salgado, _Jet broadening in flowing matter: Resummation,_ Phys. Rev. D 106, no.7, 074023 (2022) [arXiv:2207.07141 [hep-ph]].
  * [23] J. Barata, A. V. Sadofyev and X. N. Wang, _Quantum partonic transport in QCD matter,_ Phys. Rev. D 107, no.5, L051503 (2023) [arXiv:2210.06519 [hep-ph]].
  * [24] J. Barata, X. M. López, A. V. Sadofyev and C. A. Salgado, _Medium induced gluon spectrum in dense inhomogeneous matter,_ [arXiv:2304.03712 [hep-ph]].
  * [25] L. Antiporda, J. Bahder, H. Rahman and M. D. Sievert, _Jet drift and collective flow in heavy-ion collisions,_ Phys. Rev. D 105, no.5, 054025 (2022) [arXiv:2110.03590 [hep-ph]].
  * [26] Y. Fu, J. Casalderrey-Solana and X. N. Wang, _Asymmetric transverse momentum broadening in an inhomogeneous medium,_ Phys. Rev. D 107, no.5, 054038 (2023) [arXiv:2204.05323 [hep-ph]].
  * [27] M. Connors, C. Nattrass, R. Reed and S. Salur, _Jet measurements in heavy ion physics,_ Rev. Mod. Phys. 90, 025005 (2018) [arXiv:1705.01974 [nucl-ex]].
  * [28] Y. Mehtar-Tani, C. A. Salgado and K. Tywoniuk, _Anti-angular ordering of gluon radiation in QCD media,_ Phys. Rev. Lett. 106, 122002 (2011) [arXiv:1009.2965 [hep-ph]].
  * [29] S. Cao and X. N. Wang, _Jet quenching and medium response in high-energy heavy-ion collisions: a review,_ Rept. Prog. Phys. 84, no.2, 024301 (2021) [arXiv:2002.04028 [hep-ph]].
  * [30] G. Ovanesyan and I. Vitev, _An effective theory for jet propagation in dense QCD matter: jet broadening and medium-induced bremsstrahlung,_ JHEP 06, 080 (2011) [arXiv:1103.1074 [hep-ph]].
  * [31] M. D. Sievert and I. Vitev, _Quark branching in QCD matter to any order in opacity beyond the soft gluon emission limit,_ Phys. Rev. D 98, no.9, 094010 (2018) [arXiv:1807.03799 [hep-ph]].
  * [32] M. D. Sievert, I. Vitev and B. Yoon, _A complete set of in-medium splitting functions to any order in opacity,_ Phys. Lett. B 795, 502-510 (2019) [arXiv:1903.06170 [hep-ph]].
  * [33] F. Domínguez, J. G. Milhano, C. A. Salgado, K. Tywoniuk and V. Vila, _Mapping collinear in-medium parton splittings,_ Eur. Phys. J. C 80, no.1, 11 (2020) [arXiv:1907.03653 [hep-ph]].
  * [34] J. H. Isaksen and K. Tywoniuk, _Wilson line correlators beyond the large-N c,_ JHEP 21, 125 (2020) [arXiv:2107.02542 [hep-ph]].
  * [35] C. Andres, F. Dominguez, R. Kunnawalkam Elayavalli, J. Holguin, C. Marquet and I. Moult, _Resolving the Scales of the Quark-Gluon Plasma with Energy Correlators,_ Phys. Rev. Lett. 130 (2023) no.26, 262301 [arXiv:2209.11236 [hep-ph]].
  * [36] C. Andres, F. Dominguez, J. Holguin, C. Marquet and I. Moult, _A Coherent View of the Quark-Gluon Plasma from Energy Correlators,_ [arXiv:2303.03413 [hep-ph]].
  * [37] A. Tamis for the STAR Collaboration, _Measurement of Two-Point Energy Correlators Within Jets in p+p Collisions at $\sqrt{s}$= 200 GeV,_ PoS Hard Probes 2023 (to appear).
  * [38] R. Curz-Torres for ALICE Collaboration, _Measurement of the angle between jet axes and energy-energy correlators with ALICE,_ PoS Hard Probes 2023 (to appear).
  * [39] P. T. Komiske, I. Moult, J. Thaler and H. X. Zhu, _Analyzing N-Point Energy Correlators inside Jets with CMS Open Data,_ Phys. Rev. Lett. 130, no.5, 051901 (2023) [arXiv:2201.07800 [hep-ph]].
  * [40] M. Attems, J. Brewer, G. M. Innocenti, A. Mazeliauskas, S. Park, W. van der Schee and U. A. Wiedemann, _The medium-modified $g\to c\overline{c}$ splitting function in the BDMPS-Z formalism,_ JHEP 01, 080 (2023) [arXiv:2203.11241 [hep-ph]].
  * [41] J. H. Isaksen and K. Tywoniuk, _Precise description of medium-induced emissions,_ [arXiv:2303.12119 [hep-ph]].
  * [42] P. Arnold, O. Elgedawy and S. Iqbal, _Are gluon showers inside a quark-gluon plasma strongly coupled? a theorist’s test,_ [arXiv:2212.08086 [hep-ph]].
  * [43] P. Arnold, O. Elgedawy and S. Iqbal, _The LPM effect in sequential bremsstrahlung: gluon shower development,_ [arXiv:2302.10215 [hep-ph]].
  * [44] C. Andres, N. Armesto, H. Niemi, R. Paatelainen and C. A. Salgado, _Jet quenching as a probe of the initial stages in heavy-ion collisions,_ Phys. Lett. B 803, 135318 (2020) [arXiv:1902.03231 [hep-ph]].
  * [45] S. Stojku, J. Auvinen, M. Djordjevic, P. Huovinen and M. Djordjevic, _Early evolution constrained by high-p $\perp$ quark-gluon plasma tomography,_ Phys. Rev. C 105, no.2, L021901 (2022) [arXiv:2008.08987 [nucl-th]].
  * [46] C. Andres, L. Apolinário, F. Dominguez, M. G. Martinez and C. A. Salgado, _Medium-induced radiation with vacuum propagation in the pre-hydrodynamics phase,_ JHEP 03, 189 (2023) [arXiv:2211.10161 [hep-ph]].
  * [47] A. Ipp, D. I. Müller and D. Schuh, _Anisotropic momentum broadening in the 2+1D Glasma: analytic weak field approximation and lattice simulations,_ Phys. Rev. D 102, no.7, 074001 (2020) [arXiv:2001.10001 [hep-ph]].
  * [48] A. Ipp, D. I. Müller and D. Schuh, _Jet momentum broadening in the pre-equilibrium Glasma,_ Phys. Lett. B 810, 135810 (2020) [arXiv:2009.14206 [hep-ph]].
  * [49] M. E. Carrington, A. Czajka and S. Mrowczynski, _Jet quenching in glasma,_ Phys. Lett. B 834, 137464 (2022) [arXiv:2112.06812 [hep-ph]].
  * [50] M. E. Carrington, A. Czajka and S. Mrowczynski, _Transport of hard probes through glasma,_ Phys. Rev. C 105, no.6, 064910 (2022) [arXiv:2202.00357 [nucl-th]].
  * [51] D. Avramescu, V. Băran, V. Greco, A. Ipp, D. I. Müller and M. Ruggieri, _Simulating jets and heavy quarks in the glasma using the colored particle-in-cell method,_ Phys. Rev. D 107, no.11, 114021 (2023) [arXiv:2303.05599 [hep-ph]].
  * [52] K. Boguslavski, A. Kurkela, T. Lappi and J. Peuron, _Heavy quark diffusion in an overoccupied gluon plasma,_ JHEP 09, 077 (2020) [arXiv:2005.02418 [hep-ph]].
  * [53] K. Boguslavski, A. Kurkela, T. Lappi, F. Lindenbauer and J. Peuron, _Jet momentum broadening during initial stages in heavy-ion collisions,_ [arXiv:2303.12595 [hep-ph]].
  * [54] X. Du, _Heavy quark drag and diffusion coefficients in the pre-hydrodynamic QCD plasma,_ [arXiv:2306.02530 [hep-ph]].
  * [55] S. Hauksson and E. Iancu, _Jet polarisation in an anisotropic medium,_ [arXiv:2303.03914 [hep-ph]].
  * [56] L. Apolinário, _Monte Carlo modeling of jets,_ PoS Hard Probes 2023 (to appear).