The spin alignment of vector mesons emitted in heavy-ion collisions has recently been measured by the ALICE and STAR collaborations over a wide range of energies [1, 2]. The alignment is part of the so-called tensor polarization, which is a property that is exclusive to particles of spin 1 and higher. Even though there have been substantial theoretical efforts, a definite explanation for the...
Isobar collisions, $^{96}_{44}$Ru+$^{96}_{44}$Ru and $^{96}_{40}$Zr+$^{96}_{40}$Zr, at $\sqrt{s_{\mathrm {NN}}}$ = 200 GeV have been performed at RHIC. These collisions are considered to be an effective way to minimize the flow-driven background contribution to search for the possibly small CME signal. Anisotropic flow is an important tool to understand properties of the QGP medium. Elliptic...
Ultra-relativistic heavy-ion collisions at RHIC are thought to have created a Quark-Gluon-Plasma (QGP) with a very low shear viscosity in the deconfined phase. However, as the QGP hadronizes it will evolve through a hadronic phase with rapidly increasing shear viscosity. In order to fully characterize the QGP state, one has to separately determine the viscosity of the hadronic phase. Although...
sPHENIX, the first detector to be built at the Relativistic Heavy-Ion Collider (RHIC) in over two decades, will bring unprecedented measurement capabilities at RHIC energies. One of the initial physics measurements to be performed by sPHENIX concerns the charged-particle multiplicity, which utilizes the tracklet analysis method with the cluster information from the...
We study the production of charm quarks in hot QCD medium described by quasiparticle excitations of quarks and gluons. The effective masses are adjusted through the coupling to satisfy the entropy density obtained on the lattice [1]. The evolution of the QGP is described by hydrodynamic simulations in (2+1) dimensions with temperature-dependent shear viscosity taken into account [1,2]. The...
Many physics observables of interest in heavy-ion collisions require knowledge of the collision geometry. Geometric fluctuations lead to different symmetry planes of the initial geometry for each harmonic number, called participant planes. As the produced medium evolves, pressure gradients transform the initial state spatial anisotropy into final state momentum anisotropy. The angular...
HADES has a large acceptance as well as excellent particle identification capabilities and therefore allows the study of dielectron, hadron, and light nuclei production in heavy-ion collisions with great precision. The harmonic flow coefficients $v_n$ of the order $n = 1 − 6$ are measured with HADES as a function of centrality, transverse momentum, and rapidity in Au+Au collisions at 1.23...
Correlations involving the seven conserved quantities, $\{E,\vec{p},Q,S,B\}$, were modeled for heay-ion collisions at finite baryon density. The evolution of correlations as a function of relative rapidity was treated as a linear response to local thermodynamic fluctuations of on the Bjorken-model background. The entire 7x7 matrix of correlations was found to be significant, sensetive to the...
Results from heavy-ion collisions confirmed the scenario in which the deconfined state of nuclear matter, dubbed the quark--gluon plasma (QGP), undergoes a collective expansion. Collective anisotropic flow, quantified with Fourier harmonics of azimuthal distribution of particles, $v_n$, is one of the most sensitive experimental probes to constrain QGP properties. Recently developed...
The anisotropic flow parameters $(v_{n})$ offer insights into collective hydrodynamic expansion and transport properties of the produced medium at higher collision energies, while they are sensitive to the compressibility of the nuclear matter and nuclear equation of state at lower collision energies. Among them directed flow ($v_1$) describes the collective sideward motion of produced...
Studying hyper-nuclei production and their collectivity can shed light on their production mechanism as well as the hyperon-nucleon interactions under finite pressure. This is a unique opportunity for heavy-ion collisions at high baryon density region where hypernuclei production rate increases.
In this poster, we will present $v_{1}$ of the hyper-nuclei ($\Lambda$, $^{3}_{\Lambda}{\rm...
We analyze the effect of hydrodynamic fluctuations on normalized mixed harmonic cumulants ($nMHC$) [1,2] for the first time based on event-by-event simulations of high-energy heavy-ion collisions using an integrated model of an initial state model, stochastic causal fluctuating hydrodynamics, and a hadronic afterburner.
For the quantitative constraints on the transport properties of...
A hot and dense system formed in heavy-ion collisions can be characterized by studying the scaling behavior of the spatial distributions of the produced particles. In this contribution, we present intermittency analysis of the normalized factorial moments ($F\rm{_{q}}$) of the multiplicity distributions of the charged particles produced in Pb--Pb collisions as a function of phase-space...
The thermal fluctuations in the QGP medium formed in heavy ion collisions present themselves as event-wise $[p_\mathrm{T}]$ fluctuations in the final state. Recent studies have shown that the average and higher-order fluctuations of $[p_\mathrm{T}]$ in ultra-central collisions are sensitive to radial flow, random thermal motion, and nuclear deformation, and can provide constraints on the...
Besides the traditional flow studies of individual flow amplitudes $v_n$, independent information about all stages in heavy-ion evolution can be extracted from multi-harmonic correlations of flow amplitudes. The simplest realization is Symmetric Cumulants (SC), which correlate the same-order moments of two or more flow amplitudes. In recent studies, it was demonstrated that SC can reveal the...
Higher order flow harmonics provide a powerful probe of the initial geometry of heavy ion collisions, as well as the properties of the quark-gluon plasma produced in these collisions, including the transport coefficients and the degree of collective behavior. This poster presents higher order flow harmonics measurements in PbPb collisions at $\sqrt{s_{_{\mathrm{NN}}}} = 5.02$~TeV using data...
Relativistic hydrodynamics has been successful in describing space-time evolution of matter created in high-energy nuclear collisions. It is conventionally supposed that the created matter starts to behave as fluids all at once at a certain initial time. It is, however, not at all trivial from which stage after the collision the fluid picture can be applied to the system. According to the...
The mean $p_{\rm{T}}$ fluctuations in heavy-ion collisions can be related to temperature fluctuations which quantify the specific heat of the system. Any deviations from the Hadron Resonance Gas model as a function of the incident energy can be interpreted as a possible signal of criticality. In this poster we present the first efficiency corrected charged particle event-by-event mean...
The initial QGP geometry of the quark-gluon plasma (QGP) is manifested as azimuthal anisotropy in final state particles of a nuclear collision in the plane transverse to the beam direction. This study measures the Fourier coefficients $v_{2}$ and higher order harmonics of charged particle distribution in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with 2018 data collected by the...
We study the critical point effects on particle number fluctuations both in the crossover ($T > T_{\rm c}$) and mixed phase ($T < T_{\rm c}$) regions by means of molecular dynamics simulations of a Lennard-Jones fluid, motivated by the ongoing search for the QCD critical point in heavy-ion collisions.
In the crossover region, we find large fluctuations associated with the critical point in...
Charge balance functions (BFs) were introduced at the beginning of the RHIC era as a tool to investigate the evolution of particle production in heavy-ion collisions and identify the presence of delayed hadronization as an indicator of the formation of long lived isentropic expanding quark gluon plasma in high-energy nucleus-nucleus (A--A) collisions. It later emerged that BFs are rather...
The study of event-by-event fluctuations of the mean transverse momentum, $\langle p_{\rm{T} }\rangle$, could probe the nature of the phase transition and seek evidence for temperature fluctuations. In this talk, event-by-event $\langle p_{\rm{T} }\rangle$ and higher order fluctuations of charged particles produced in pp collisions at $\sqrt{s}=5.02$ TeV, Xe--Xe collisions at...
Two-particle transverse momentum correlator $G_{2}$ was measured based on data collected from Pb--Pb collisions at $\sqrt{s_{\rm NN}} = 2.76\;\text{TeV}$. The evolution of the longitudinal width of the $G_{2}$ correlator vs. collision centrality nominally provides information about the specific shear viscosity, $\eta/s$, of the medium formed in the collisions. The $G_{2}$ correlator was also...
Measurements of high-multiplicity pp and pA collisions at LHC energies have revealed that these small collision systems exhibit some quark-gluon plasma-like features, such as collective behaviour and strangeness enhancement, formerly thought to be achievable only in nucleus-nucleus collisions. A proposed method to narrow down the origin of these phenomena is to study the effect of MultiParton...
Despite the success of hydrodynamic models in describing heavy-ion collisions, there have long been questions about its regime of validity. Recently-derived conditions on the causality of the hydrodynamic equations [1] can give a concrete answer --- if evolution is acausal, it is not a faithful representation of the underlying QCD theory. It is now known that current simulation models reach...
The method of moments has been employed to derive relativistic fluid-dynamical theories from the Boltzmann equation for the past decades [1]. This approach consists in expanding the single-particle distribution function using a basis of irreducible momenta, where the expansion coefficients are the irreducible moments of the nonequilibrium distribution function [2]. Unlike the Chapman-Enskog...
When studying the properties of the Quark-Gluon Plasma (QGP) formed in relativistic heavy ion collisions, it is necessary to classify the events based on the size and shape of the QGP. Typically, events are categorized by mapping the impact parameter, which cannot be measured directly, to a bulk observable that varies monotonically with it, such as soft particle production. In the mapping,...
The Ridge behavior in high-multiplicity proton-proton collisions has been discussed a lot since it was first reported. However, small systems like proton-proton collisions are not enough to generate a medium called Quark-Gluon Plasma (QGP) in which the Ridge behavior is explained with high-order flows. In this work, we suggest the pure kinematic mechanism between jets and medium partons as...
Nowadays, relativistic dissipative hydrodynamics including effects of finite viscosities is commonly used to extract transport properties of the quark gluon plasma (QGP), such as shear viscosity and bulk viscosity, from experimental data. However, according to the fluctuation-dissipation relation (FDR) in non-equilibrium statistical physics, fluctuations and dissipation are always accompanied...
