We study theoretical uncertainties in the hydrodynamic description of relativistic heavy-ion collisions by examining the full nonlinear causality conditions [1] and quantifying their effects on flow observables [2]. The causality conditions impose physical constraints on the maximum allowed values of inverse Reynolds numbers during the hydrodynamic evolution. We develop a new numerical scheme...
We develop a new parametric 3-dimensional initial condition for low-energy heavy-ion collisions based on collision geometry for a multistage hybrid framework. The longitudinal structure of the collision profile is constrained by rapidity-dependent experimental measurements, especially the directed flow of pions and protons (i.e., $v_1(y)$). We introduce a baryon stopping parameter which...
Building upon Ref. [1], we present an improved three-dimensional dynamical initialization model for heavy-ion collisions, implementing local energy-momentum conservation and baryon charge fluctuations at string junctions [2]. These improvements lead to an excellent description of the charged hadron and net proton rapidity distributions in Au+Au collisions from 7.7 to 200 GeV [3]. Based on...
Determining QCD properties via experimental observations is an
essential part of the heavy-ion program, and a crucial aspect of any
such study is an accurate assessment of uncertainty. This uncertainty
comes not only from experiments but also from theoretical modeling.
Bayesian inference methods provide an ideal framework for a systematic
treatment of these sources of uncertainty and an...
“Hybrid Hadronization” is a Monte Carlo package that hadronizes systems of partons. It smoothly combines quark recombination, applicable when distances between partons in phase space are small, and string fragmentation appropriate for dilute parton systems, following the picture outlined by Han et al. [PRC 93, 045207 (2016)]. Hybrid Hadronization can be applied to a variety of systems from...
Quantum Chromodynamics (QCD), the theory of strong interactions, predicts that at sufficiently high temperature and/or high energy density normal nuclear matter converts into a deconfined state of quarks and gluons, known as the Quark-Gluon Plasma (QGP). To investigate the phase diagram of QCD matter, the Relativistic Heavy Ion Collider (RHIC) started the first phase of the Beam Energy Scan...
Determination of equation of state for nuclear matter at high baryon density region is one of the most important motivations for RHIC Beam Energy Scan program. Directed flow ($v_{1}$), which is the first harmonic coefficient in the Fourier expansion of the final state azimuthal distribution of produced particles relative to the collision reaction plane, is one of good probes to early stage of...
Models based on statistical hadronisation were found to be applicable for ultra-relativistic heavy-ion experiments where high nucleon transparency is present. It is not well established whether such models are also valid for the part of the QCD diagram where the collision energies are lower (of the order of a few GeV). In our previous work, by implementing spherical fireball geometry and...
In high-energy heavy-ion collisions, strong and transient electromagnetic fields (~$10^{14}~[\rm{T}]$) are induced inside generated hot and dense QCD medium.
The space-time evolution of the electromagnetic field in electrically conducting nuclear matter is completely different from that of vacuum; the lifetime of it becomes much longer than that in the vacuum. Also, the electrical...
In the EKRT model for ultrarelativistic heavy-ion collisions, we compute the initial fluctuating QCD-matter energy densities from NLO pQCD and saturation, and describe the subsequent space-time evolution of the system with dissipative fluid dynamics, event by event [1,2,3]. This model agrees remarkably well with the low-$p_T$ flow observables measured in Pb+Pb and Xe+Xe collisions at the LHC,...
In this talk, we analyze the factorization ratio $r_n(\eta_p^a,\eta_p^b)$ in Xe+Xe and Pb+Pb collisions [1] using event-shape engineering within the integrated dynamical model [2,3] constructed of the Monte-Carlo Glauber model for the initialization, rfh for 3+1D relativistic fluctuating hydrodynamics with hydrodynamic fluctuations [2], and JAM for hadronic cascades [4]. We also address...
The initial spatial asymmetry of the overlapping zone between two colliding nuclei in heavy ion collisions gives rise to the final momentum anisotropy characterized by the anisotropic flow parameters. The efficiency of conversion from initial spatial anisotropy ($\epsilon_n$) to final momentum anisotropy ($v_n$) is quantified by the linear correlation between $\epsilon_n$ and $v_n$. We have...
Extraction of the Quark-Gluon Plasma (QGP) transport properties (i.e. specific shear viscosity $\eta/s$) is a prime goal of the heavy-ion programs at the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC). Correlators that are sensitive to both initial-state effects and final-state viscous attenuation can give invaluable constraints for temperature ($T$) and chemical...
We present result on an anisotropic transverse flow of kaons ($K^+$, $K^0_S$ and $K^-$) in Au+Au collisions at $\sqrt{s_\mathrm{NN}} = 2.42\,\mathrm{GeV}$ measured with HADES. It was proposed already in mid-nineties that kaon flow around its production threshold might be a good probe for kaon-nucleon potential, and consequently for nuclear equation-of-state [1]. The presented analysis was...
