We report the first measurements of two-particle transverse-momentum correlations 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 correlator...
磁化 QCD 物质中的守恒荷涨落与关联，以及温度涨落，在手征恢复相变和禁闭解除相变过程中被广泛研究，包括交叉区域以及临界终点（ CEP）附近区域。相关计算在三味（Polyakov 扩展的）Nambu–Jona-Lasinio 模型框架下进行。对于有限温度下的交叉过程，我们重点研究这些物理量对外部磁场的依赖关系，并发现重子数与其他守恒荷之间的关联对外部磁场最为敏感。对于有限温度和有限密度下的 CEP 区域，我们系统地计算了最高达十阶的涨落与关联，以理解其临界性质。
We investigate spin hydrodynamic properties with an focus on entropy production for massive spin 1/2 particles. We consider particle collisions both with and without the influence of chiral anomalies such as the chiral magnetic or vortical effects, encoded by Berry curvature. This manifests as a spatial shift ($\Delta$). In doing so we first define and entropy that makes use of the matrix...
Event-by-event fluctuations of the mean transverse momentum of particles provide a direct probe of collective radial expansion of the system formed in high-energy collisions. We present the first measurement of transverse-momentum-dependent radial flow fluctuations, characterized by the observable $v_0(p_{\mathrm{T}})$, in small collision systems. The measurement is performed using CMS data...
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...
Quarkonia are excellent probes for studying the interactive properties of quark-gluon plasma formed in relativistic heavy-ion collisions. To correctly interpret the observed suppression of quarkonium production in $\text{Au}+\text{Au}$ collisions at $\sqrt{s_{\text{NN}}}$ = 200 GeV, the cold nuclear matter (CNM) effects in $p+\text{Au}$ collisions are quantified by the nuclear modification...
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...
Directed flow $v_1$ has been used to probe the early dynamics in high-energy nuclear collisions. The vector meson $\phi(s\bar{s})$, with a mass comparable to that of light baryons and weak hadronic interactions, provides a unique probe of the interplay between particle production mechanisms and early-stage dynamics in high-density nuclear matter.
In this talk, we report measurements of...
Measurements of identical pion femtoscopy offer insights into collision dynamics, such as collective expansion, geometry of the collision zone at freeze-out, final state interactions, etc. In addition to the quantum interference and Coulomb interactions among the pion pairs, Coulomb interactions between the pair and the net positive charge in the emitting source affect the final correlation...
This report investigates the infrared structure of QCD through the lens of the Cho–Faddeev–Niemi decomposition and Faddeev–Niemi effective theory. We argue that gluon knots, as topological solitons characterized by the Hopf invariant, constitute the relevant infrared ground-state degrees of freedom of Yang–Mills fields. Within this framework, we present a unified mechanism for monopole...
We construct a light-front Hamiltonian description of the nucleon in an enlarged low-energy Fock space containing the valence $q q q$ sector, the sea-flavor $q q q q \bar{q}$ sector, and the gluonic hybrid $q q q g$ sector. The $q q q \leftrightarrow q q q q \bar{q}$ mixing is taken to be generated by the chiral pair of $\sigma$ - and $\pi$-type operators used in the nucleon-pentaquark...
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...
We investigate the production of open-flavor hadrons in $ pp $ collisions at $ \sqrt{ s_{ NN } } $ = 5.02 TeV using the parton and hadron cascade model PACIAE. We introduce string tension enhancement mechanisms towards dipole and double-junction strings in the string fragmentation hadronization model. The transverse momentum spectra and the baryon-to-meson ratios of light and heavy...
