Elliptic flow constitutes the hallmark observable of collective dynamics in heavy-ion collisions, revealing hydrodynamic properties of dense nuclear matter. Strongly interacting Fermi gases provide a clean, controllable strongly correlated quantum fluid to study universal phenomena, bridging ultracold atom experiments and nuclear physics. This talk will focus on higher-order harmonic flow...
In this talk, we will present the inclusive J/ψ production in proton-proton collisions at \sqrt{s}= 5.02, 7 and 13 TeV. A quantitative analysis of the relative contributions for different production mechanisms (NRQCD, cluster collapse, and non-prompt) in the inclusive J/ψ production, as well as the energy and rapidity dependence of these contributions will be shown. We will also discusse the...
In relativistic heavy-ion collisions, jet substructure observables provide unique access to the interactions between energetic partons and the hot, dense QCD medium known as the Quark–Gluon Plasma (QGP). Among them, the jet invariant mass ($M_{\mathrm{jet}}$) is particularly sensitive to parton virtuality evolution and the pattern of final-state radiation. However, measurements of jets with...
We will study the Spin Alignment and Phase Structure of Thermal QGP under Rotation with high energy heavy-ion collisions.And then,we will investigate the Anomalous Magnetic Moment and Phase Transition of the Magnetized QCD Background; The Rotation Effect on the Deconfinement Phase Transition are investigated with Holographic QCD method. And finally, we make Summary and Conclusions.
We use Bayesian inference with deep-learning surrogate models to quantitatively extract the in-medium heavy quark (HQ) potential from bottomonium nuclear modification factors ($R_{AA}$) measured in Pb--Pb collisions at $\sqrt{s_{NN}}=5.02$ and $2.76$ TeV and Au--Au collisions at $\sqrt{s_{NN}}=200$ GeV. The real and imaginary parts of the potential are parametrized and embedded in a...
Motivated by color coherence and decoherence effects in the QCD medium, we propose a theoretical framework that combines vacuum-like emissions and medium-induced radiation to study jet quenching and its dependence on jet cone sizes and substructure. In our approach, a jet produced at a hard scale $Q$ first undergoes vacuum-like evolution, as described by the well-established...
Chiral matter exhibits a variety of intriguing anomalous transport phenomena that originate from the chiral anomaly. Prominent examples of such phenomena include the chiral magnetic effect and the chiral vortical effect. In the hydrodynamic regime, we demonstrate that in a chiral plasma subject to an external magnetic field, the chiral vortical effect can induce a new type of...
Energy-energy correlator (EEC) is an excellent jet substructure observable owning to its strong sensitivity to jet physics at different scales. Using a hybrid Pythia 8 + LBT framework, we perform a complete realistic simulation on medium modification of heavy and light flavor jet EEC in heavy-ion collisions. A clear flavor hierarchy is observed for jet EEC in both vacuum and QGP due to the...
In this talk, I will report our recent study of the thermodynamics of accelerated pure gluonic matter. We investigate the one-loop Polyakov-loop effective potential in uniformly accelerated systems, where acceleration serves as an external parameter for the confinement--deconfinement transition. We compare thermodynamic quantities obtained in the Rindler frame with those in the conformally...
Heavy quarks are produced in hard scatterings at the very beginning of a heavy-ion collision. As a result, they experience all subsequent stages of the collision, and their dynamics are particularly sensitive to the properties of the quark–gluon plasma (QGP) phase. Recent studies have demonstrated that a fluid-dynamical description of heavy-quark transport in the QGP, combined with a realistic...
In high-energy heavy-ion collisions, high-energy jets produced by initial hard scatterings interact with the quark–gluon plasma (QGP) and lose energy during their propagation. A single jet may contain multiple partons, which can interact with the QGP either coherently or decoherently. Current Pb+Pb collision experiments have reached a center-of-mass energy of 5.02 TeV, and jet transverse...
Heavy quark (HQ) momentum ($\kappa$) and spatial diffusion ($D_s$) coefficients are computed in a non-perturbative thermal QCD medium in the presence of a background magnetic field of arbitrary strength. Both perturbative (Yukawa) and non-perturbative (string) effects are incorporated via the in-medium HQ potential, obtained from the resummed
gluon propagator ($D_{\mu\nu}$). To that end, an ansatz...
The production of light nuclei and hypernuclei in relativistic heavy-ion collisions provides a unique opportunity to investigate the formation mechanism of loosely bound states and the structure of hypernuclei. In particular, coalescence models predict a strong suppression of hypertriton (${}^{3}_{\Lambda}\mathrm{H}$) production relative to ${}^{3}\mathrm{He}$ in small collision systems...
The medium produced at RHIC Beam Energy Scan (BES) energies is baryon-rich. This enhanced baryon stopping not only leads to a splitting in the yields of baryons and anti-baryons, but has also been observed experimentally to produce a splitting in their flow coefficients. Hydrodynamic models have struggled to reproduce this baryon-antibaryon flow splitting with the correct magnitude and sign,...
Lee-Yang edge singularities (LYEs) are singularities that limit the analyticity of the thermodynamic potential in the complex chemical potential plane and provide important information on the phase structure. In this work, we extend the functional renormalization group approach for the PQM model to the complex chemical potential plane and investigate its analytic structure. We identify the...
Jet quenching provides a powerful probe of the properties and space-time structure of the quark-gluon plasma (QGP) created in high-energy nuclear collisions. In particular, the dependence of jet observables on the jet cone size offers direct sensitivity to the angular redistribution of energy induced by medium-modified parton showers and medium response. In this work, we investigate the...
We systematically investigate the scaling properties of the transverse momentum spectra for pions, kaons, and protons in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV, as well as in U+U collisions at $\sqrt{s_{NN}}$ = 193 GeV, across different centrality classes, using experimental data from the collaborations at the Relativistic Heavy Ion Collider...
In ultra-peripheral collisions (UPCs), coherent J/$\psi$ photoproduction provides a sensitive probe of the nuclear gluon distributions. The STAR collaboration has reported differential measurements of photoproduced J/$\psi$ in Au+Au UPCs, providing important constraints on nuclear gluon structure and sub-nucleonic fluctuations in heavy nuclei. Compared with Au+Au collisions, isobaric systems...
Studies of light nucleus production, including deuterons, and helium nuclei, in heavy-ion collisions are essential for understanding the dynamics of nuclear matter under extreme conditions and provide valuable insights into the underlying equation of state. Compound yield ratios, such as $\rm N_t \times N_p/N_d^2$ and $\rm N_{^4He} \times N_p / (N_{^3He} \times N_d)$, have been proposed as...
Production of $\psi(4040)$, $\psi(4160)$ and $\psi(4415)$ mesons in
ultrarelativistic heavy-ion collisions
Xiao-Ming Xu
Department of Physics, Shanghai University, Baoshan, Shanghai 200444, China
$\psi(4040)$, $\psi(4160)$ and $\psi(4415)$ mesons are higher charmonia that
can be individually interpreted as the $3 ^3S_1$, $2 ^3D_1$ and $4 ^3S_1$
quark-antiquark states. In...
Radial flow is conventionally studied through transverse-momentum ($p_{T}$) spectra and blast-wave model analyses, which provide information on the average collective expansion and kinetic freeze-out properties of the system. In contrast to the extensively studied anisotropic-flow coefficients $v_{2}$ and $v_{3}$, the $p_{T}$-differential fluctuations of radial flow remain largely unexplored....
Neutron-star measurements constrain the
pressure–energy-density relation but leave the micro-
scopic composition of dense matter unresolved. A poly-
tropic index Γε < 1.75 and sound speed C2
s = 1/3 have
both been used as signatures of quark degrees of free-
dom. We test these interpretations by calibrating a nu-
cleonic reference domain in the (Γε, P/Pfree) plane. A
Taylor metamodel...
In the present talk, I will review recent progress on (Anti-)(Hyper-)Nuclei production, structure, and polarization in High-Energy Nuclear Collisions
Directed flow ($v_1$) and elliptic flow ($v_2$) provide complementary probes of the equation of state, degrees of freedom, and collective dynamics of the produced medium. Here, we present STAR measurements of collective flow for identified strange and multistrange hadrons in heavy-ion collisions at RHIC.
Using high-statistics data from the STAR Beam Energy Scan Phase-II (BES-II)...
In the established paradigm of jet quenching in relativistic heavy-ion collisions, jets from initial hard parton scatterings are suppressed due to their interaction with the quark-gluon plasma (QGP), serving as crucial tomographic probes of QGP properties. Within the linear Boltzmann transport model, we find that the QGP is also capable of absorbing and reprocessing energy deposited by the...
Spin correlations of back-to-back dihadrons can emerge in unpolarized high-energy collisions, offering opportunities for unpolarized experiments to access spin-dependent fragmentation functions. In particular, transverse spin correlations of a partonic $q\bar q$ pair can manifest themselves through di-hadron production, providing a novel probe of the chiral-odd fragmentation function...
Heavy-ion collisions are studied to probe hot, dense nuclear matter, known as the quark–gluon plasma (QGP). While flow-like signatures observed in pp and p–Pb collisions at the LHC suggest that QGP-like behavior may emerge even in small systems, jet quenching has so far remained unobserved in such collisions. To better understand the transition between small and large collision systems, the...
In heavy-ion collisions, heavy quarks serve as sensitive probes of the quark–gluon plasma (QGP), as they traverse and interact with the constituents of the medium throughout its entire evolution. In proton–proton (pp) collisions, the study of their production offers stringent tests of perturbative quantum chromodynamics (pQCD) calculations and serves as an essential baseline for the...
The thickness of the neutron skin ($\Delta r_{np}$) in $^{48}$Ca remains uncertain, with parity‑violating electron scattering (CREX) and ab initio calculations favoring a thin skin while energy density functionals prefer larger values. Heavy‑ion collisions at relativistic energies can probe the skin through its geometric imprint on the quark‑gluon plasma, but a thicker skin also increases the...
We study the Chiral Magnetic Effect (CME) in relativistic heavy-ion collisions using charge fluctuations and their correlations generated in the early stages of the collision. Employing the 2+1 flavor Polyakov-loop-extended Nambu–Jona-Lasinio (PNJL) model, we compute the charge separation associated with the CME. A central challenge in interpreting these correlations experimentally is...
The $N\Omega$ system is a promising candidate for a dibaryon bound state. To enable a direct comparison between lattice QCD and experiment, we calculate the $^5S_2$ $N\Omega$ interaction in $(2+1)$-flavor lattice QCD at the physical point ($m_\pi\simeq137.1$ MeV and $m_K\simeq501.8$ MeV) with the time-dependent HAL QCD method. Because the coupling to the $D$-wave octet-octet channels is weak,...
The triangular flow coefficient ($v_{3}$) is the third term in the Fourier expansion of the azimuthal distribution of particles produced in heavy-ion collisions. A non-zero $v_{3}$ arises from event-by-event fluctuations in the positions of participant nucleons within the collision zone. Higher order flow coefficients, particularly $v_{3}$ and higher harmonics, exhibit enhanced sensitivity to...
The deuteron carries baryon number two and is abundantly produced in the baryon-rich matter created in heavy-ion collisions. Its number fluctuations can provide insight into QCD matter at high baryon density and may be sensitive to critical-point physics. Since deuterons are formed from nucleons, their fluctuations are closely connected to baryon-density fluctuations and can complement...
The MIP Timing Detector (MTD) for the CMS (Compact Muon Solenoid) experiment is designed as the timing detector for the HL-LHC era to mitigate the effects of high pile-up using 4-dimensional spatial information. Precise timing information from the MTD will improve the quality of physics analysis, particularly through particle identification in the low-momentum region, especially with data from...
For the high-energy terminal of High Intensity heavy-ion Accelerator Facility (HIAF), we have proposed an experimental project using Huizhou Hadron Spectrometer (HHaS) [1]. It covers a wide range of physics subjects, containing the studies of light hadrons, hypernuclei, and the nuclear matter phase diagram, as well as the search for the phenomena beyond the standard model. The concept of HHaS...
In ultrarelativistic heavy-ion collisions, a state of deconfined quarks and gluons, the quark-gluon plasma (QGP), is created. As the system cools, it evolves into a hot and dense hadronic medium. Precise measurements of the spectral functions of low-mass vector mesons (ρ, ω, φ ) in the dilepton channel can provide information on possible restoration of chiral symmetry. As part of the ALICE...
Femtoscopic correlation measurements provide a unique tool to investigate the space-time structure of particle-emitting sources created in high-energy collisions. Using quantum statistical effects and final-state interactions between particles, femtoscopic analyses offer direct access to the source size, emission dynamics, and collective behavior of the produced matter on the femtometer scale....
Prompt photons refer to photons produced at the level of partonic scatterings, both directly in the initial 2->2 interaction (\textit{direct}) prompt photons), or from the fragmentation of partons through next-to-leading order (NLO) interactions (\textit{fragmentation} prompt photons). However, the majority of photons produced in hadronic collisions originate from the decays of neutral mesons...
In heavy-ion collisions, collective flow arises from the response of the produced medium to the initial-state geometry. Measurements of azimuthal particle correlations provide powerful tools to investigate the emergence of collective behaviour, the transport properties of hot QCD matter, and the role of nuclear geometry in the initial state. The LHCb experiment offers unique capabilities for...
We discuss numerical simulations of relativistic spin hydrodynamics solved by physics-informed neural networks (PINNs) [1]. We take advantage of PINNs to explicitly impose the total angular momentum, i.e., the sum of orbital and spin angular momentum, accurately conserved by including the conservation law directly in the loss function as a training target. This enables controlled numerical...
Heavy-ion collisions (HICs) is a unique tool for studying properties of hot and condensed nuclear matter. HICs at HIRFL-CSR energies can create nuclear matter with baryon density as high as 2 to 3 times of the saturation density. The CSR External-target Experiment (CEE) at HIRFL facility is a larger acceptance spectrometer to study QCD phase structure, Equation of State (EoS) and sub-threshold...
Hypernuclei are nuclear bound states composed of nucleons and one or more hyperons. Precise measurements of hypernuclei properties and production yields in heavy-ion collisions provide important insights into the hyperon–nucleon interaction and hypernuclear production mechanisms. The second phase of the Beam Energy Scan program at RHIC (BES-II) provides a unique opportunity to investigate the...
Thermal dileptons, produced throughout the entire evolution of relativistic heavy-ion collisions, are unique penetrating probes of the hot and dense medium as they escape without being subject to strong interactions. By measuring the transverse momentum distribution of direct virtual photons and elliptic flow ($v_2$) of dileptons emitted from the hot QCD medium, one can extract key properties...
We investigate the applicability of hydrodynamics in small collision systems by comparing viscous anisotropic hydrodynamics (VAH) with conventional viscous hydrodynamics (VH). In $\sqrt{s}=13$ TeV p+p collisions, VAH successfully describes $v_2\{2\}$, $v_3\{2\}$, and the negative $c_2\{4\}$, whereas VH requires evolution characterized by large shear Knudsen numbers. We further compare VAH and...
The expansion dynamics and transport properties of the quark-gluon plasma (QGP) are essential for understanding the evolution of matter created in relativistic heavy-ion collisions [1–5]. In particular, comparisons between different collision systems provide a powerful way to isolate the system-size dependence of collective expansion and its fluctuations, thereby improving sensitivity to the...
The neutron skin, in which the neutron distribution extends farther out than the proton distribution in neutron-rich nuclei, is characterized by the radius $R$ and the diffuseness $a$ of each distribution, and is closely connected to the nuclear equation of state. At present, parity-violating electron scattering is essentially the only direct measurement of this quantity. We investigate a...
A central question in strong-interaction physics, governed by quantum chromodynamics (QCD), is whether femto-scale droplets of quark–gluon plasma (QGP) form in small collision systems involving projectiles significantly smaller than heavy ions. Collisions of light ions such as 16O and 20Ne offer a unique opportunity to probe the emergence of collective behavior in QCD matter. This work...
Event-by-event mean transverse momentum ($p_{\rm T}$) fluctuations provide insight into the initial-state geometry fluctuations, the thermodynamic properties, and the collective evolution of hot and dense QCD matter. In this talk, we will present STAR measurements of event-by-event mean $p_{\rm T}$ fluctuations in Au+Au collisions from the Beam Energy Scan programs, covering collider-mode as...
Isospin symmetry, one of the fundamental symmetries underlying the strong interaction, predicts similar production rates of charged and neutral kaons in high-energy collisions. However, recent measurements by the NA61/SHINE Collaboration indicate an excess production of charged over neutral kaons, suggesting significant isospin symmetry breaking that challenges the expectation, and the...
The anisotropic flow of direct photons is a sensitive probe of the initial geometry in relativistic heavy-ion collisions. Alpha clustering in light nuclei can enhance the initial spatial anisotropies, which can result in larger direct-photon anisotropic flow. In this work, we studied the production and anisotropic flow of direct photons for both central and peripheral collisions of...
We report the first measurements of two-particle transverse-momentum correlations (variance) for midrapidity charged particles in fixed-target Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=3.0$--$7.7$ GeV using data collected by STAR during the Beam Energy Scan Phase II program [1]. Combined with previous BES-I measurements at $\sqrt{s_{\mathrm{NN}}}=7.7$--$200$ GeV [2], the relative dynamical...
The study of multi-baryon interactions, particularly those involving strange quarks, is key to understanding dense nuclear matter and the equation of state of neutron stars. While two-body nucleon-nucleon ($N$-$N$) and hyperon-nucleon ($Y$-$N$) forces are relatively well constrained, genuine three-body interactions remain largely unexplored. By comparing systems composed solely of nucleons...
Fluctuations of conserved quantities are proposed as sensitive observables to search for the QCD critical point in heavy-ion collisions. Recently, the STAR experiment has conducted precision measurement of net-proton fluctuations in Au+Au collisions at √sNN = 7.7 – 27 GeV, during the RHIC Beam Energy Scan II program [1] and reported the preliminary results of proton number fluctuation in...
Ultracentral nucleus–nucleus collisions provide a uniquely stringent test of fluctuating initial conditions: although their average transverse geometry is nearly azimuthally symmetric, measurements reveal an unexpected near degeneracy of elliptic and triangular flow, whereas conventional hydrodynamic calculations generally predict (v_2{2}>v_3{2}). An independent challenge is posed by the...
Spin correlations are among the fundamental quantum observables in many-body systems, yet direct measurements of two-particle spin correlations in relativistic heavy-ion collisions remain challenging. Existing spin studies have mainly focused on single-particle phenomena, such as hyperon polarization and vector-meson spin alignment, while genuine two-particle spin correlations in the produced...
We investigate the global spin polarization of $\Lambda$ hyperons and the multi-strange hyperons $\Xi^{-}$ and $\Omega^{-}$ in Au+Au collisions across the RHIC Beam Energy Scan II (BES-II) energy range, $\sqrt{s_{NN}}=7.7$--$27$ GeV. The polarization is computed using the modified Cooper--Frye formula, which includes contributions from thermal vorticity, the thermal shear tensor, and the...
Strangeness production is a sensitive probe of quark-gluon plasma formation and of how it varies with collision-system size. In central heavy-ion collisions at both RHIC and LHC, significant $\Omega$/$\phi$ ratio enhancement with relation to peripheral collisions has been observed at intermediate transverse momentum. It is also reported by ALICE that the strange-hadron-to-pion yield ratios...
We have used the parton and hadron cascade model PACIAE together with the Dynamically Constrained Phase-space Coalescence model (DCPC) to study the $T_{cs0}^{*}(2870)^{0}$ production in $pp$ collision at $\sqrt{s}$ = 7 TeV, following the LHCb observation of $T_{cs0}^{*}(2870)^{0}$ in the $B^{-}\to D^{-}D^{0}K^{0}_{S}$ decays in $pp$ collisions at $\sqrt{s}$ = 7, 8, and 13 TeV [PRL...
Onset of hydrodynamics in the hot medium created in relativistic heavy-ion collisions is a crucial theoretical question. Addressing this problem in a first-principle manner, requires a real-time, non-perturbative simulation of a large scale quantum system, as hydrodynamic behavior emerges only when approaching the continuum limit. The exponentially large Hilbert space of quantum states...
The longitudinal structure of the quark–gluon plasma (QGP) is the missing third dimension in our picture of its initial state. It records how energy is deposited along the beam, how quantum fluctuations in the colliding nuclei shape the plasma, and how collective expansion converts this geometry into final-state momentum correlations. Accessing it is notoriously difficult: short-range nonflow...
The Electron-Ion Collider (EIC), which is scheduled to begin operations at Brookhaven National Laboratory in the 2030s, will explore the quark and gluon structure of nucleons and nuclei, including the emergence of gluon saturation at high densities. Through high-energy collisions of polarized electrons with protons and nuclei, the EIC will provide new insights into the structure and dynamics...
Recently, we have conducted a series of studies on the non-perturbative dynamics of QCD matter under extreme conditions using a unified lattice-calibrated holographic framework. First, addressing the rotational response of pure gluonic matter, we established a rotation-magnetic correspondence and revealed a chromomagnetic-induced inertia inversion mechanism. We show that melting chromomagnetic...
The distribution of particles is highly anisotropic in the initial stage of a heavy-ion collision. We demonstrate that this anisotropy induces a sizable effect on the spin alignment of vector mesons. We study two different production mechanisms for ϕ and K∗0 mesons, on one hand the coalescence of quarks and on the other that of pseudoscalar mesons. In the quark-coalescence picture where ϕ and...
Nuclear clustering and intrinsic deformation are important manifestations of many-body correlations in nuclei. At RHIC and the LHC, collective flow and transverse-momentum correlations have been extensively explored as probes of initial-state nuclear structure [1]. Building on recent studies of $\alpha$ clustering and U+U deformation at CSR energies [2,3], we investigate whether...
The longitudinal local polarization $(P_{z,s2})$ of $\Lambda$ and $\bar{\Lambda}$ hyperons exhibits a second-harmonic azimuthal modulation that is closely related to the anisotropic expansion and velocity-gradient structure of the produced medium. Measurements of local polarization in 200 GeV Au + Au and isobar collisions at RHIC exhibit similar centrality dependence, increasing in more...
ALICE 3 is the next-generation detector system proposed for LHC Runs 5 and 6. Its main tracking system is based on CMOS Monolithic Active Pixel Sensor (MAPS) technology, providing broad pseudorapidity coverage and consisting of an Inner Tracker (IT) and an Outer Tracker (OT). This talk focuses on the ongoing efforts on the OT project by the Korea ALICE group (KoALICE).
The OT is composed of...
We compute the time evolution of the quarkonium density matrix in the background glasma field, the primordial state of matter in relativistic heavy-ion collisions, and show how the color of the quarkonium state is randomized. This color randomization is of particular interest because it drives the quarkonium out of its color-singlet state, leading to dissociation. The resulting suppression of...
Understanding the origin of prompt D0 meson elliptic flow helps us to learn how charm quarks interact with the quark-gluon plasma (QGP), with the initial state determined by the event-by-event collision geometry. The event shape-dependent elliptic flow can be understood in detail using the event shape engineering (ESE) technique. ESE correlates light hadron elliptic flow, a proxy for the...
Understanding how protons and neutrons are located differently in an atomic nucleus can provide fundamental information on nuclear structure and have far-reaching implications for astrophysics. A precise determination of this important difference, often quantified by the so-called neutron skin thickness, is challenging both theoretically and experimentally. Here we show how one can use a new...
We present a novel quantum algorithmic framework for simulating Quantum Chromodynamics (QCD) on quantum computers. By employing the axial gauge ($A_3 = 0$) and the addition of non-local gauge fixings, this framework explicitly eliminates all local redundant gauge degrees of freedom. Within this formalism, we rigorously establish upper bounds on both the qubit overhead and the gate complexity...
At this conference, I will present our latest findings on the properties of gluodynamics in an accelerated frame of reference, investigated via first-principles lattice simulations. To study the accelerated system, we employ Rindler coordinates, wherein a comoving observer cannot receive signals from beyond the Rindler horizon. We investigate the confinement-deconfinement phase transition...
Linearly polarized quasireal photons from relativistic heavy ions can transfer their polarization to coherently photoproduced vector mesons, producing a second-harmonic modulation in their decay angular distributions. A positive modulation has been observed for spin-0 pions from coherent $\rho^{0}$ decays, using the $\rho^{0}$ transverse momentum direction as the polarization reference, while...
During the LHC Long Shutdown 3 (2026–2030), the ALICE collaboration will upgrade its three innermost tracking layers with the Inner Tracking System 3 (ITS3), the first fully cylindrical, wafer-scale silicon vertex detector. Built on 65 nm CMOS MAPS technology, ITS3 features silicon thinned to 50 µm and bent into self-supporting cylindrical layers at radii of 19, 25, and 32 mm. Wafer-scale...
Spin correlation is believed to be a significant contribution to vector meson spin alignment. In this work, we study the generation of spin correlation through fluctuations of the chromomagnetic field in the quark-gluon plasma medium. We show that anisotropic fluctuations generically lead to finite spin alignment of vector mesons. We study two sources of anisotropic chromomagnetic field...
Polarization and spin alignment have emerged as important tools for investigating the dynamical properties of the strongly interacting matter produced in relativistic nuclear collisions. Spin-dependent observables provide access to different aspects of the collision depending on the particle species and the choice of the spin-quantization axis. Correlations with the event or reaction plane can...
Entanglement generated in the early stage of relativistic heavy-ion collisions (HIC) is considered a direct and fundamental source for understanding fast thermalization, entropy production, and evolution. Spin entanglement in QCD, arising from non-commutative geometric effects of quantum fields, provides a new avenue to explore the quantum informational footprint of the QCD topological vacuum...
Recent theoretical advances have shown that collective flow imparts a large asymmetry to both the momentum broadening distribution and the medium-induced radiation spectrum of jet partons. In this work, we present the first inclusion of the full flow-induced anisotropic radiation spectrum in a heavy ion jet Monte Carlo as a large scale overhaul of the open-source [APE (Anisotropic Partonic...
Author
Kanato Matsutani$^{1,2}$ for the ePIC Japan Group
$^1$Graduate School of Advanced Science and Engineering, Hiroshima University, Japan
$^2$WPI-SKCM2, Hiroshima University, Japan
Abstract
The Electron-Ion Collider (EIC) at Brookhaven National Laboratory will collide polarized electrons with protons and nuclei to explore the partonic structure of matter. Hadron identification in...
Direct photons escape the collision zone with negligible final-state interaction and retain information about the evolving QCD medium. Their low-momentum yield and elliptic flow $v_2$, however, remain challenging to describe simultaneously. Standard calculations treat the incoming partons as uncorrelated. We ask whether correlations surviving from the early non-equilibrium stage leave a...
Hyperon spin correlations have recently attracted significant interest as a probe of QCD spin dynamics. A recent theoretical study suggests that the spin correlation for Λ hyperon pairs is a sensitive probe to separate strong-force-field-induced vector meson spin alignment from hydrodynamic effects, and to probe spin-orbit coupling, polarization transfer, and possible spin entanglement in...
A FAZIA (Forward-angle A and Z Identification Array) telescope consists of two silicon pad detectors and a CsI(Tl) scintillator. Using the ΔE–E correlation and pulse shape analysis (PSA), the FAZIA detector can identify charges up to Z = 52 and discriminate isotopes up to Z = 25.
Presently, the FAZIA upgrade project is ongoing with the goal of extending the beam-energy coverage and lowering...
An autoregressive neural sampler writes a lattice configuration site by site, each site conditioned on the sites already written, and it returns independent samples with an exact likelihood. Each conditional sees only a context window of fixed reach, and nothing in the architecture says how far that reach has to extend.
Set the reach one unit short of what the target needs and the interior...
Doubly heavy tetraquarks $(QQ\bar{q}\bar{q})$ states with two heavy quarks and two light antiquarks have been actively discussed for a long time. Among them, a doubly charmed tetraquark $T_{cc}^+$ was reported by the LHCb Collaboration in 2022: A narrow peak appears in the $D^0D^0\pi^+$ mass spectrum around 273 keV below the $D^{*+}D^0$ threshold, with its isospin $I$,spin $J$, and parity $P$...
Heavy quarkonium production can be described as perturbative heavy quark-antiquark pair production and nonperturbative hadronization. Studying quarkonium production inside jets provides insight into quarkonium evolution in the nonperturbative process, which can be characterized by the jet fragmentation fraction of the quarkonium transverse momentum with respect to the enclosing jet. LHCb...
High-energy nuclear collisions provide a unique environment to study isospin transport in strongly interacting QCD matter. While the strong interaction approximately conserves isospin, collisions involving nuclei with different neutron-to-proton $(N/Z)$ ratios offer a direct way to investigate how the initial isospin of the system is reflected in final-state hadron production....
The Cooling-storage-ring External-target Experiment (CEE) is a large-acceptance spectrometer designed for the study of nuclear matter under extreme conditions in heavy-ion collisions at intermediate energies. A reliable detector alignment and track-matching procedure is essential for the reconstruction of charged particles and for subsequent physics analyses.
In this work, we present the...
We present the first comprehensive study of dilepton production from a hot, magnetized quark
gluon plasma in heavy-ion collisions (HIC), incorporating realistic, time-dependent, and spatially
inhomogeneous magnetic field profiles within an analytically solvable Gubser flow background. This
framework provides a significant improvement over previous static calculations with...
We calculate the electrical conductivity of the quark-gluon plasma (QGP) state using the Arnold-Moore-Yaffe (AMY) effective kinetic theory, incorporating nonperturbative inputs via the medium distribution functions and the elastic scattering kernel. The calculation is performed for the $(2+1)$-flavor system over the temperature range $0.8\leq T/T_c\leq2.2$, relevant for the deconfined matter...
The search for quark–gluon plasma (QGP)-like collectivity in small collision systems remains a central goal of high-energy nuclear physics. Recent results from O$+$O collisions suggest that strongly coupled, near-perfect-fluid behavior may emerge even in such small systems, motivating a detailed investigation of jet quenching in systems of reduced size. In this work, we study hadron and jet...
The speed of sound, $c_s$, reflects the thermodynamic properties of the quark–gluon plasma produced in relativistic heavy-ion collisions. In ultracentral collisions, recent studies have conjectured that $c_s^2$ can be extracted from the logarithmic dependence of the mean transverse momentum, $\langle p_T\rangle$, on the charged-particle multiplicity, $\langle...
A key objective of high-energy nuclear physics is the search for the onset of gluon saturation phenomena in the limit of extreme gluon densities. Photon-induced vector meson production in ultraperipheral heavy-ion collisions (UPCs) offers a unique and powerful probe of the gluon distribution in nuclei. The $\phi$ meson, with its mass around 1 GeV, lies at the boundary of hard scales between...
In this talk, we investigate high-order temperature fluctuations within a multi-charge Einstein--Maxwell--Dilaton holographic model with flavor-dependent $u$, $d$, $s$ sectors, calibrated by lattice QCD results. We extract the fluctuation observables $c_n$ ($n = 2, \dots, 6$) from high-order temperature derivatives of the pressure along realistic freeze-out trajectories with multiple conserved...
We investigate a rotating quantum system subjected to a co-aligned external magnetic field. The gauge-invariant kinetic angular momentum is of particular importance because as the thermodynamic conjugate of the angular velocity, it determines the equilibrium state. Its relevance is further motivated by experimental observations of extreme fluid vorticity in heavy-ion collisions. We develop a...
We investigate the late-time asymptotic solutions and attractor structure of the spin density in minimal causal spin hydrodynamics in Gubser flow. After deriving the differential equation governing the spin density, we obtain its late-time asymptotic solutions and identify both attractors and repellers in the corresponding numerical solutions. We then map these solutions back to flat Minkowski...
Hypernuclei, bound states consisting of nucleons and hyperons, provide a unique opportunity to study the hyperon-nucleon ($Y$-$N$) interaction and the role of strangeness in nuclear matter. Because free hyperon targets are unavailable and hyperon–nucleon scattering data are limited, hypernuclei provide an important means of constraining hyperon–nucleon interactions. Measurements of hypernuclei...
Ultra-peripheral Ru+Ru and Zr+Zr collisions at $\sqrt{s_{\mathrm{NN}}}=200~\mathrm{GeV}$ at RHIC provide a controlled setting for investigating nuclear-structure effects in the photonuclear production of forward neutrons. Although the two isobars have the same mass number, they differ in proton number and photonuclear response, making their neutron-tagged Coulomb-dissociation cross-section...
We study the dynamics of heavy quarks in the quark-gluon plasma in the presence of non-Markovian memory effects using a generalized Langevin framework. Time-correlated thermal noise with a power-law decay is generated through a fractional differential equation formulated in terms of the Caputo fractional derivative of order $\nu$. The role of memory is analyzed through several dynamical...
The photon radiation induced by rescattering in a magnetized medium is investigated in relativistic heavy-ion collisions. Within the high-energy limit, the photon emission rate and the associated electromagnetic energy loss are derived using the Gyulassy-Levai-Vitev formalism at first order in opacity, for a quark jet propagating through a quark-gluon plasma along a background magnetic field....
In non-central heavy-ion collisions, ultra strong magnetic fields can be generated by the nuclear fragments. The fluctuations of these electromagnetic fields, originating from event-by-event variations in the initial nucleon distributions, were proposed in Refs. [1, 2]. In this talk, I present our recent study of the impact of the electromagnetic-field fluctuations on the charge-dependent flow...
Quark jets are powerful probes of the matter created in ultrarelativistic heavy-ion collisions, from the dense gluon fields of the initial-stage Glasma to the hot quark-gluon plasma. In this talk, I present our recent progress on developing a non-perturbative computational framework for in-medium jet evolution based on the light-front QCD Hamiltonian approach. By treating the jet as a fully...
During non-central ultra-relativistic heavy-ion collisions, the colliding nuclei carry a large global angular momentum. A part of this angular momentum is believed to be transferred to the quark-gluon plasma (QGP) medium leading to the spin polarization/alignment of the final state particles such as $\Lambda, K^{*}, \phi$. While the spin polarization of $\Lambda$ hyperons along global angular...
The spin polarization of $\Lambda$ hyperon in low-energy Au-Au collision can be generated from the nonlocal nucleon-nucleon scattering. The Lagrangian of baryon-meson interaction is obtained from the chiral perturbation theory, and we introduce a wave packet for the incoming nucleons to describe the nonlocal collision. We evaluate the spin dependent cross sections with the approximations that...
Thermal dileptons serve as ideal probes for studying the properties of the quark-gluon plasma (QGP) created in heavy-ion collisions. In particular, the dilepton production rate is directly proportional to the in-medium spectral function of the electromagnetic current, so that the invariant-mass spectra of dileptons encode both the temperature evolution and the microscopic structure of the...
The observation of spin polarization in non-central heavy-ion collisions has opened new directions in the development of relativistic hydrodynamic theories. Many theoretical frameworks have been developed to explain the phenomenon of polarization of the detected hadrons. One such framework is spin hydrodynamics, in which spin degrees of freedom, or equivalently the total angular momentum, are...
Two loop thermodynamic equation of state (EOS) at finite chemical potential is studied at one stable droplet size. Due to the presence of the chemical potential in two loop correction, formation of bubble/droplet of quark gluon plasma (QGP) is modified, and at this particular stable droplet the thermodynamic parameters such as pressure, energy density, interaction measurement, entropy,...
