We present an innovative procedure to account for unavoidable contributions from volume (or system size) fluctuations to experimentally measured cumulants of particle multiplicity distributions produced in relativistic nuclear collisions. For the first time we extract participant fluctuations directly from the data used for the fluctuation analysis, i.e., without involving model calculations...
Fluctuations of conserved quantities are proposed as a powerful observable to search for the QCD critical point. Recently, proton cumulants from central Au+Au $\sqrt{s_{NN}}$ = 3 GeV collisions were reported, which implies that hadronic interactions are dominant at 3 GeV and the QCD critical point could exist at the collision energies higher than 3 GeV. The baryon-strangeness correlation is...
The AdS/CFT correspondence, which connects strongly coupled conformal field theories in $N$ dimensions to gravity in $N+1$ dimensional Anti-de Sitter space, has provided valuable insights into the non-perturbative aspects of QCD. Soft-wall AdS/QCD is a phenomenological model that uses a dilaton field to introduce confinement, while a scalar field is dual to the chiral condensate. The...
Directed flow of particles is an important feature seen in heavy-ion collisions and is a sensitive probe to the equation of state (EoS) of the matter produced in the collisions. Model calculations have also predicted that directed flow could be sensitive to the softening of EoS associated with a first order phase transition. Directed flow of protons and anti-protons are also of interest as...
Exploring the space-time extent of particle production is an important goal of heavy-ion physics, and substantial effort has been made in order to understand the underlying physics behind the experimental observations of non-Gaussian behavior. In experiments, femtoscopic (momentum) correlations are utilized to gain information about the space-time geometry of the particle emitting source....
In high-energy nuclear collisions, the light nuclei production is sensitive to the temperature and density of the system at freeze-out. It is also predicted to be sensitive to local baryon density fluctuations and can be used to probe the QCD phase transition. The second phase of Beam Energy Scan (BES-II) program at RHIC was completed in 2021. The high-statistics data recorded by the STAR...
Jet quenching parameter $\hat{q}$ is essential for characterizing the interaction strength between jet partons and nuclear matter. Based on the quark-meson (QM) model, we develop a new framework for calculating $\hat{q}$ at finite chemical potentials, in which $\hat{q}$ is related to the spectral function of the chiral order parameter. A perturbative calculation up to the one-loop order...
Higher-order fluctuations of the net-proton number distributions in heavy-ion collisions are expected to be sensitive to a QCD critical point. These fluctuations can be obtained by measuring various order of cumulants, $C_n$, of the net-proton multiplicity distributions. The collision energy dependence of net-proton $C_4/C_2$ from Beam Energy Scan I hints at a possible enhancement from...
In the exploration of the nuclear matter phase diagram, the susceptibilities of conserved charges are useful theoretical tools to probe the existence of a $1^\text{st}$ order phase transition, and a possible critical endpoint. They can be related to the cumulants of the considered net-charges, for which STAR collaboration recently published experimental measurements of proxies, in Au-Au...
We investigate how the event-by-event fluctuations of the final-state distribution function of nucleons physically affect the yield ratio of light nuclei based on the coalescence model.
The yield ratio of light nuclei, $N_tN_p/N_d^2$ (with $N_t$, $N_p$, and $N_d$ being triton, proton, and deuteron numbers, respectively) [1,2], is one of the observables suggested for a possible signal of the...
