The very far forward, or ``fragmentation'', region of heavy-ion collisions is critically understudied. The physics of this region is incredibly rich and may lead to insight into a variety of other problems. We present a simple model for understanding the hydrodynamics of the fragmentation region, arguing that a density of 2-3 times nuclear saturation density is reached. We also present a...
The finite nuclear thickness affects the energy density $\epsilon(t)$ [1] and conserved-charge densities [2] such as the net-baryon density $n_B(t)$ produced from the primary NN collisions of heavy ion collisions. While the effects are small at high collision energies compared with the standard Bjorken model of the initial state, they are large at low collision energies, where the nuclear...
Soft radiative corrections to in-medium g->gg splitting processes have been known to produce double-logarithmic enhancement of the splitting rate. In our previous work on corrections to the leading order LPM effect, we have shown that this double-log enhancement is accompanied by a sub-leading single log behavior. It has been shown by previous authors that these double log enhancements can be...
Relativistic hydrodynamics is surprisingly predictive, even in the presence of large gradients and large deviations from equilibrium. In some of its incarnations, the method of moments can be used to justify the hydrodynamic behavior of a relativistic gas. However, it can’t be directly generalized. If long range interactions are introduced through a medium-dependent mass or a semi-classical...
The high quality experimental data on hard probes in heavy-ion collisions call for a more precise theoretical description of jet evolution in a quark-gluon plasma. To accomplish that we study jet fragmetation via $1\to 2$ final-state parton splittings in the medium. In earlier works [1,2] the authors have usually calculated these processes by invoking one or two approximations: the large-$N_c$...
Currently there exists no viable ``ab initio'' approach to simulate QCD dynamics at the LHC/RHIC that is universally applicable. This profoundly limits our understanding of the formation, real-time evolution and hadronization of the quark-gluon plasma in heavy ion collisions. Quantum computing may provide a potential solution to efficiently simulate these real-time dynamics within the...
The observation of long-range azimuthal anisotropies in small collision systems triggers pressing questions concerning the applicability of fluid dynamics and whether ensembles of only a small number of particles may be effectively treated as fluids. We propose to use experiments on expanding clouds of cold atoms to answer the latter question. We consider strongly-interacting fermions confined...
A central ingredient in calculations of scattering processes in the high energy saturation regime of QCD is the light cone wavefunction. It is a universal QCD quantity encoding the light cone gauge partonic structure of a high energy projectile, and a necessary ingredient in cross section calculations for different scattering processes. This talk will report on the recent calculation of the...
The measurements of the spin observables open a new window for understanding the quantum properties of the hot and dense medium created in heavy-ion collisions. However, there are still several puzzling phenomena begging for satisfactory explanations. Particularly, the measured spin-alignments of the vector boson is unexpectedly large compared to a class of model calculations. To investigate...
The Low theorem, proven only for diffractive photon radiation, cannot be extended to inelastic hadronic collisions with multi-particle production. Comparison with incorrect calculations led to the so-called soft-photon puzzle. We describe soft photon production within the color-dipole approach. The required quark distribution in the colliding hadrons at a soft scale is calculated employing the...
The search for gluon saturation is one of the major goals of the future Electron-Ion Collider (EIC). Significant progress has been made in advancing saturation physics to a precision science as we prepare for the EIC era. Focusing on inclusive dijet production in deeply inelastic electron-nucleus, we contribute to these efforts in two ways. First, we quantify the size of kinematic twist and...
The formulation of a causal and stable theory of relativistic viscous hydrodynamics is an important field of current research, with direct applications to the modeling of ultrarelativistic heavy-ion collisions. While the theory of relativistic ideal fluids is well established, the incorporation of dissipation introduces qualitatively new challenges due to the need to maintain relativistic...
Suppression of open heavy flavors and quarkonia in heavy-ion collisions is among the most informative probes of the quark-gluon plasma. Interpreting the full wealth of data obtained from the collision events requires a precise understanding of the evolution of heavy quarks and quarkonia as they propagate through the nearly thermal and strongly coupled plasma. In particular, a complete...
Determining the existence and the location of the QCD critical point remains a major open problem, both theoretically and experimentally. In this work, I present a new way of reconstructing the equation of state in the vicinity of the nearest thermodynamic singularity (the Lee-Yang edge singularity in the crossover region) from a truncated Taylor series expansion in baryon chemical potential....
