Conveners
分会场三: 重离子物理（一）
- Xin-Nian Wang (Central China Normal University)
- Hongxi Xing (South China Normal University)
分会场三: 重离子物理（二）
- Zhongzhou Ren (Tongji University)
- Guang-You Qin (Central China Normal University)
分会场三: 重离子物理（三）
- Daicui Zhou (Central China Normal University)
- Bo-Qiang Ma (Peking University)
分会场三: 重离子物理（四）
- Shi Pu (University of Science and Technology of China)
- Zebo Tang (University of Science and Technology of China)
ALICE实验进展
A non-extensive (3+1)-dimensional hydrodynamic model for multi-particle production processes, NEX-CLVisc, is developed in the framework of the CLVisc package where the viscous corrections are turned off. It is based on non-extensive statistics and assumes that non-extensive effects exist in the initial conditions, the equation of state and the hadron kinetic freeze-out procedure. The model is...
$\phi$ has relatively small hadronic interaction cross sections and it can be used to study the properties of nuclear medium at the early stage. The recombination model indicates that the $\Omega/\phi$ ratio will be enhanced at low and medium transverse momentum $(p_{\text{T}})$, where thermal strange quarks dominate the production of $\Omega$ and $\phi$ in the QGP. Therefore, the...
In this study, the canonical formulation of the spin hydrodynamics of Dirac fermions is examined within a power counting scheme, where the spin variables are considered to be at the same order as the conventional hydrodynamic variables. An entropy-current analysis with a general spin potential reveals the importance of incorporating both the three components of spin density associated with...
Measurements of heavy flavor quark correlations in heavy-ion collisions are crucial to understand the flavor dependence of quark energy loss mechanisms in hot and dense QCD matter. In addition to the heavy-ion collisions, experimental measurements of heavy flavor correlations in p+p collisions can provide insights into the contributions of perturbative and non-perturbative QCD processes to the...
The Phi meson and Omega baryon provide unique probes of the properties of the quark-gluon plasma (QGP) at hadronization in relativistic heavy-ion collisions. Using the quark recombination model with the quark phasespace information parameterized in a viscous blast wave, we perform Bayesian inference of the shear and bulk viscosities of the QGP at hadronization with a temperature of T ≈ 160 MeV...
Measurements of charm-strange meson and charm-baryon production in pp and heavy-ion collisions at the LHC are fundamental to investigate the charm-quark hadronisation across collision systems.
In this contribution, the final results of the ALICE Collaboration on the production of strange ($\mathrm{D_s}^+$ , $\Xi_\mathrm{c}^{0,+}$, $\Omega_\mathrm{c}^0$) and non-strange ($\mathrm{D}^0$ ,...
Energy correlators have shed light on the properties of QCD splitting in vacuum, which should be modified due to nuclear effects in a deconfined QCD matter such as the quark-gluon plasma. By employing the recently developed multi-stage jet evolution framework JETSCAPE, we have investigated the nuclear modification of energy correlators for inclusive jets in heavy-ion collisions. We find energy...
In this talk, We will present a theoretical study on the production of the heavy-flavour decay lepton (HFL) in high-energy nuclear collisions at the LHC. The pp-baseline is calculated by the FONLL program, which matches the next-to-leading order pQCD calculation with the next-to-leading-log large-$p_T$ resummation. The in-medium propagation of heavy quarks is driven by the modified Langevin...
At leading order in QCD coupling constant, we compute the energy loss per traveling distance of a heavy quark $dE/dz$ from elastic scattering off thermal quarks and gluons at a temperature $T$, including the thermal perturbative description of soft scatterings ($-t<-t^{\ast}$) and a perturbative QCD-based calculation for hard collisions ($-t>-t^{\ast}$). Within this soft-hard factorization...
The longitudinal spin transfer represents the probability density of producing longitudinally polarized hadrons from longitudinally polarized quarks or circularly polarized gluons. It thus was usually measured in polarized reactions or high-energy collisions where weak interaction dominates. In this work, we propose the dihadron polarization correlation as a novel probe of this quantity. Such...
In-jet production is a useful tool to separate the contribution from the hard processes and the underlying events. In this letter, we find the in-jet requirement enhances the heavy flavor baryon-to-meson ratio more when a color re-connection mechanism (CR mode2) describes hadronization in p+p, which is opposite to the light flavor case. It indicates the hard process contribution alone will...
The measurement of jets recoiling from a trigger hadron provides unique probes of medium-induced modification of jet production. Jet deflection via multiple soft scatterings with the medium constituents or single-hard Moli`ere scatterings off quasi-particles in the medium are expected to modify the azimuthal correlation between the trigger hadron and recoiling jet. The $R$-dependence of...
Particles associated with the jet will be deflected from their initial direction due to the scatterings with the thermal partons flowing in the QGP fluid. Such deflections depend on the energy of the jet, the local energy gradient, and the local flow velocity. In general, the soft particles will drift towards the direction of the flowing medium, away from the center of the jet cone where the...
理解强相互作用物质的性质及其相结构对于我们深入认识宇宙演化和可见物质结构具有重要科学意义。近二十年来，高能重离子碰撞实验中观测到了许多间接证据表明强相互作用夸克-胶子等离子体（sQGP）的存在。因此，探索高重子密度下的量子色动力学（QCD）相结构，特别是寻找一阶相变边界和QCD临界点在相图中的位置，成为高能核物理研究的重要目标之一。从2010年到2021年，RHIC-STAR实验分两个阶段完成了能量扫描计划，收集了质心能量从200 GeV到3 GeV下金核-金核碰撞实验数据。本报告将讨论在RHIC能量扫描计划中(BES-I&BES-II)关于QCD相图和相变临界点的实验研究进展。
Phase diagram – theory
Searching the QCD critical point is one of the most important goals of the relativistic heavy-ion collisions. It is essential to build a realistic dynamical model near the QCD critical point and predict the characteristic signature induced by critical fluctuations in experimental measurements. By studying the dynamics of the conserved net-baryon density near critical point, it was found that...
In this work, we extend the two-flavor Nambu--Jona-Lasinio model to one capable of exploring quark and nuclear matter consistently. With an extra term standing for quark-nucleon interactions, nucleons could automatically emerge as color-singlet three-quark entities by following a process similar to mesons. Besides the quark part in mean field approximation, both mesons and nucleons could...
Fluctuations and correlations of conserved charges are sensitive observables to study QCD phase structure. In particular, the baryon-strangeness correlations may be used to study the change of phases in the matter created in heavy-ion collisions.
In this work, we present the measurement of baryon-strangeness correlations in Au+Au collisions from beam energy scan program at STAR. This is...
With experimental data of DIS involving transversely polarized proton, we have calculated the 3-D charge density inside a polarized proton, which is found to have a significant non-spherical symmetry. Then we have calculated the properties of E-M field generated by a single transversely polarized proton. Based on them, the E-M field generated in small collision system p+A which involving a...
We investigate the magnetized QCD matter and chiral phase transition in a (2 + 1)-flavor Nambu–Jona- Lasinio (NJL) model at finite temperature and chemical potential by comparing the contributions from the tensor spin polarization (TSP) and anomalous magnetic moment (AMM) of quarks. On the other hand, we study the properties of the shear viscosity coefficient of quark matter near the chiral...
Using AdS/CFT correspondence, we study the imaginary part of heavy quarkonia potential from thermal fluctuations in a strongly coupled plasma. We perform the analysis in a rotating deformed AdS black-hole background. It is shown that the presence of angular velocity decreases the onset of imaginary potential thus
enhancing quarkonia dissociation, in agreement with previous findings of the...
Within proton-lead collisions collected by the LHCb detector at nucleon-nucleon center-of-mass energy of 5 and 8.16 TeV, a rich set of open charm hadrons is observed with abundant statistics. Thanks to the LHCb forward acceptance that is complementary to general purpose detectors and excellent performance in particle reconstruction and identification, these charm states are studied down to...
$~~~~$PHENIX experiment group points out that in the measurements of the $\pi^0$ nuclear modification factor $R_{dAu}^{\pi^0}$, $\langle N_{\rm coll} \rangle$ can be biased by the event-selection [1], which can be effectively reduced by using the direct $\gamma$ yield at large $p_{\rm T}$ to determine the $\langle N_{\rm coll}^{\gamma} \rangle = {\rm Y}_{dAu}^{\gamma^{\rm dir}}/{\rm...
The recent observation of jet-associated deuteron production in pp collisions at √s = 13 TeV by the ALICE Collaboration opens a new window to study the production mechanism of light nuclei as well as the phase-space structure of jets produced in high-energy nuclear collisions. Here, we investigate jet effects on deuteron production in both pp and p-Pb collisions at the LHC energies, using the...
We demonstrate the recently proposed nucleon energy-energy correlator (NEEC) fEEC (x, θ) can unveil the gluon saturation in the small-x regime in eA collisions. The novelty of this probe is that it is fully inclusive just like the deep-inelastic scattering (DIS), with no requirements of jets or hadrons but still provides an evident portal to the small-x dynamics through the shape of the...
Nucleon spin structures and opportunities at EicC
The neutron skin thickness of the benchmark nuclei 208^Pb is crucial for our understanding of the equation of state of nuclear matter. Several observables in relativistic heavy ion collisions are found to be sensitive to the neutron skin, and the uncertainties from the bulk evolution can be canceled out by the collision of its isobaric partner. In this talk, we discuss the effect of the...
In this talk I will review our recent efforts to understand the polarized Transverse-Momentum-Dependent fragmentaion functions (TMD FFs) . Recent BELLE results on $\Lambda/\bar\Lambda$ polarization in $e^+e^-$-annihilations stimulate a series of progress from several groups to understand the polarized TMD FF $D_{1T}^\perp$. Based on the fundamental isospin symmetry of QCD, we propose a new...
We report our recent progress on the study of semi-inclusive deep inelastic scattring in the target fragmentation region with a polarized lepton beam and polarized nucleon target. In this region, the nonperturbative effects are factorized into fracture functions. We derive the results of structure functions up to twist-3 at the tree level of pQCD, and up to one loop level at twist-2. At the...
The shape phase transition for certain isotope or isotone chains, associated with the quantum phase transition of finite nuclei, is an intriguing phenomenon in nuclear physics. A notable case is the Xe isotope chain, where the structure transits from a $\gamma$-soft rotor to a spherical vibrator, with the second-order shape phase transition occurring in the vicinity of $^{128−130}$Xe. In this...
It is usually believed that physics in off-equilibrium state can be equivalently studied using equilibrium state with suitable metric perturbation. We point out it is not the case for spin polarization phenomena: the exisiting chiral kinetic theory in curved space fails to recover all the couplings between spin and hydrodynamic gradients [1]. We present a new form of chiral kinetic theory in...
非对心相对论重离子碰撞中产生的系统具有极强的涡旋结构，垂直于反应平面方向的轨道角动量可导致末态超子的整体极化(global polarization)，而沿着束流方向的集体流涡旋效应则导致超子的局域极化现象(local polarization)。超子的自旋极化效应作为探索强相互作用物质流体性质的新方法，目前已取得了丰富的实验测量和理论研究结果，同时也存在一些亟需解决的问题，如末态磁场的影响、整体极化的碰撞系统尺寸依赖性、低能区的局域极化性质等。
本次报告中，我们将介绍RHIC-STAR实验上BES-II能区金核-金核碰撞以及200 GeV...
We derive the chiral kinetic equation in non-Abelian gauge field with consistent semiclassical expansion. Within new expansion scheme, we disentangle the Wigner equations up the second order and find that Wigner equations do not lead to constraint equations. We integrate the covariant chiral kinetic equations in eight-dimensional phase space and obtain the chiral kinetic equations...
STAR合作组在《自然》杂志上发表了他们对高能重离子碰撞中$\Lambda$超子整体极化和$\phi$，$K^{*0}$矢量介子整体自旋排列的实验结果[1,2]，不仅证实了夸克物质整体极化这一新现象[3,4]，使自旋极化的研究成为高能核物理前沿新方向，而且表明在相对论性重离子碰撞中，夸克和反夸克在反应平面法线方向上可能存在很强的自旋关联，从而使夸克自旋关联的研究成为当前该方向新的增长点。在文献[5]中，我们提出了一种系统性的方法来描述夸克物质中的这种关联，并将其分类为局域和长程夸克自旋关联。我们的研究表明有效的夸克自旋关联包括直接源于动力学过程的真正自旋关联，以及考虑其它自由度平均引起的诱导关联。我们还展示了如何通过测量矢量介子的自旋密度矩阵以及超子-超子和超子-反超子的自旋关联来研究这种关联，并阐明了这些可观测量与夸克和反夸克自旋关联之间的关系。本报告的目标是系统介绍[5]中关于夸...
We present a new derivation of relativistic second-order spin hydrodynamics for quantum systems using Zubarev’s non-equilibrium statistical-operator formalism. This is achieved by a systematic expansion of the energy-momentum tensor, the spin tensor and the charge current to second order in deviations from equilibrium. As a concrete example, we obtain the relaxation equations for the...
Exploring the location of the critical end point (CEP) in the Quantum Chromodynamics (QCD) phase diagram is an important scientific problem that has remained unsolved for decades. Recent studies suggest that the CEP may exist within the QCD matter produced in the beam energy scan project of heavy ion collisions at $\sqrt{s_{NN}} = 3-7.7$ GeV. First-principle Lattice QCD calculations are...
Understanding the properties of hypernuclei helps to constrain the interaction between hyperon and nucleon, which is known to play an essential role in determining the properties of neutron stars. Experimental measurements have suggested that the hypertriton ($^3_\Lambda \text{H}$), the lightest hypernucleus, exhibits a halo structure with a deuteron core encircled by a $\Lambda$ hyperon at a...
The yield ratio of light nuclei produced in heavy-ion collisions, defined as $N_t \times N_p/N_d^2$, is a promising probe for the critical endpoint in the QCD phase diagram. In the coalescence model of light nucleus production, the triton yield $N_t$ and deuteron yield $N_d$ are sensitive to the relative distance $\Delta r$ between each pair of nucleons in the Wigner function. However, the...
Despite extensive measurements on the production yields of light nuclei in heavy-ion collisions, a consensus on their formation mechanism remains elusive. In contrast to normal nuclei, hypernuclei carries strangeness and can offer an additional dimension for such studies. In particular, the hypertriton ${}^{3}_{\Lambda}{\rm H}$, a bound state consisting of a proton, neutron and $\Lambda$...
