Conveners
Initial State: (1)
- Raju Venugopalan
Initial State: (2)
- Sangyong Jeon
Initial State: (3)
- Yen-Jie Lee (Massachusetts Inst. of Technology (US))
Heavy quarks, i.e. charm and beauty, are produced at the initial stage of heavy-ion collisions, on a time scale shorter than the medium formation time, and are sensitive to the large initial magnetic field produced perpendicular to the reaction plane (defined by the impact parameter direction and beam direction) in non-central heavy-ion collisions. In the presence of a large initial magnetic...
We study the hydrodynamization process in the aftermath of ultrarelativistic heavy-ion collisions using effective kinetic theory simulations and different observables. For the pressure ratio $P_T/P_L$, we observe that its late-time evolution becomes universal in units of the kinetic relaxation time for sufficiently large couplings signaling the onset of a hydrodynamical attractor. In contrast,...
Incoherent J/$\psi$ photoproduction is sensitive to fluctuations of the gluonic structure of the target. Thus, the measurement of $\rm{J/\psi}$ photoproduction off the colliding hadron sheds light on the initial state of QCD and provides important constraints on the initial conditions used in hydrodynamical models of heavy ion collisions. In this talk, we present the first measurement of the...
Hydrodynamic simulations of the quark-gluon plasma (QGP) permit us not only to gauge the transport properties of hot QCD matter from data, but also to constrain the conditions that set the stage for the formation of such matter. Recent measurements from RHIC and LHC demonstrate that the QGP initial condition is impacted by the shape and radial structure of the colliding nuclei. Based on a...
One of the main challenges in the theory of heavy ion collisions is understanding how an initial state of two highly Lorentz-contracted nuclei acquires the features of a hydrodynamic plasma in a characteristic time of 1 fm/c. Arguably, the most successful descriptions of this out-of-equilibrium stage have been established by finding so-called โattractorโ solutions in the various (simplified)...
The LHCb detectorโs forward geometry provides unprecedented access to
the very low regions of Bjorken x inside the nucleon. With full particle ID and
a fast DAQ, LHCb is able to fully reconstruct plentiful charged particles and
neutral mesons, as well as relatively rare probes such as heavy quarks, providing
a unique set of constraints on nucleon structure functions. This contribution...
There is increasing interest in using high-energy collisions to probe the structure of nuclei, in particular with the high-precision data made possible by collisions performed with pairs of isobaric species. A systematic study requires a variation of parameters representing nuclear properties such as radius, skin thickness, angular deformation, and short-range correlations, to determine the...
In heavy nuclei the neutron distribution has a larger spatial extent than the proton distribution. This size difference represents the so-called neutron skin and is determined by the strong nuclear force in the same regime as that determining the masses and radii of neutron stars. The neutron skin of $^{208}$Pb, owing to its simple structure and large neutron excess, has been the target of...
Baryon number is a strictly conserved quantity in QCD and is conventionally assumed to be divided equally among the three valence quarks in baryonic matter. An alternative model is the baryon junction: a Y-shaped configuration of nonperturbative gluons that is connected to all three valence quarks and carries the baryon number. Neither of these theories has been experimentally verified. ...
In relativistic heavy ion collisions, the charged ions produce an intense flux of equivalent photons. Thus, photon-induced processes are the dominant interaction mechanism when the colliding nuclei have a transverse separation larger than the nuclear diameter. In these ultra-peripheral collisions (UPCs), the photon provides a clean, energetic probe of the partonic structure of the nucleus,...
We first assemble a full set of the Boltzmann Equation in Diffusion Approximation (BEDA) for studying thermalization/hydrodynamization and quark production in out of equilibrium systems. In the BEDA, the time evolution of a generic system is characterized by four space-time dependent quantities: the jet quenching parameter $\hat qโโโโ$, the effective temperature $T_*$ and two others that...
Determining the structure of protons and nuclei at high energy is one of central goals of the heavy-ion collisions and the future Electron-Ion Collider (EIC). We first use Bayesian inference within the color glass condensate framework to extract the proton shape fluctuations from HERA exclusive vector meson production data at $x = 10^{-3}$. With this input, we employ the JIMWLK evolution for...
We use QCD effective kinetic theory to calculate far-from-equilibrium dynamics in the presence of quarks on an event-by-event basis within the KoMPoST framework. We present non-equilibrium response functions and dynamical evolution pertinent to the early time dynamics of heavy-ion collisions at the highest energies. The KoMPoST framework with conserved baryon, strangeness, and electric charges...
Many atomic nuclei have a deformed intrinsic shape that affects the initial-state geometry of the related collider experiments, and hence the flow coefficients observed in the final states. We use collisions of deformed nuclei to study the connection between nuclear structure at low energy and the effective theory of high energy QCD. Along with 16O, the clustered and deformed structure of 20Ne...
Constraining the initial strong electromagnetic field effects, three-dimensional structure of the initial state, and the transport properties of the Quark-Gluon Plasma (QGP) at different temperatures ($T$), and baryon chemical potentials ($\mu_B$) are critical objectives of the heavy-ion program at RHIC. The dominance of Faraday+Coulomb effect during the initial stages of non-central heavy ion...
With the tremendous accomplishments of RHIC and the LHC experiments and the advent of the future electron-ion collider on the horizon, the quest for compelling evidence of the color glass condensate (CGC) has become one of the most aspiring goals in the high energy quantum chromodynamics research. Pursuing this question requires developing the precision test of the CGC formalism. By...
Proton-lead collisions at LHC energies offer a unique possibility to investigate initial state effects in nuclear collisions. Thanks to its wide acceptance, ATLAS can measure several probes that can help characterize these effects over a wide kinematic range. By analyzing the centrality dependence of dijet production, it is possible to investigate the suppression of dijet events in central...
