The global spin polarization of hyperons in heavy-ion collisions have been investigated by including spin-correlation effects among their constituent quarks. The available data on global spin polarizations of hyperons and spin alignments of vector mesons provide constraints on phase-space functions of the spin polarization and correlation. These constraints can lead to inequalities under some approximations, which might provide possible clues for the presence of quark spin correlation inside hyperons at lower collision energies.

As an extended and more complete version of the primary QCD nucleation model presented in [Phys. Rev. C 95, 024907 (2017)], the new model introduces explicitly the transition balance and formulates it in both macroscopic and microscopic descriptions. The microscopic description of the transition balance in QCD nucleation is implemented in a kinetic parton cascade model and tested for a first-order phase transition from gluons to pions in a one-dimensional expansion with Bjorken boost invariance.

Using the $\mathrm{HYDJET}++$ model, we study the production of multistrange particles $(\varphi$ and $\mathrm{\Omega })$ in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=$ 11.5, 19.6, 27, 39, and 200 GeV as functions of transverse momentum and centrality. The model calculations employ earlier freeze-out hypersurfaces for multistrange particle production and are compared with STAR experimental data. Results indicate that the ++ model demonstrates a better agreement with experimental data for multistrange particles at higher energies, particularly in relation to early thermal freeze-out. Meanwhile, the default version performs more accurately for lighter, nonstrange particles at the same energy scales. We also analyze identified particle and mixed particle ratios, providing insights into strangeness enhancement. The results provide additional constraints on parton energy loss models, contributing to a more precise determination of the transport properties of hot and dense QCD matter.

We present a theoretical formalism for calculating first-order-in-opacity radiative energy loss that incorporates the spatial and temporal temperature evolution of the quark-gluon plasma (QGP) in a finite-size quantum chromodynamics medium with dynamical (i.e., moving) constituents. The derived expressions allow for general temperature profiles within a local-equilibrium (slowly varying) approximation, enabling detailed evaluations of radiative energy loss across different medium-evolution scenarios. Importantly, the resulting kernel applies to single partons $(R=0)$ and, after imposing the finite-cone selection, to the radiative out-of-cone contribution from a jet-initiating parton, providing a unified starting point for precision QGP tomography.

In the extended Linear-$\sigma$ Model (eLSM), the chiral phase structure of meson states, including pseudoscalars ($J^{pc}=0^{-+}$), scalars ($J^{pc}=0^{++}$), vectors ($J^{pc}=1^{--}$), and axial vectors ($J^{pc}=1^{++}$), is investigated with the mean-field approximation. A systematic comparison between SU(3) and SU(4) configurations is provided. It has been found that the estimations of meson masses derived from SU(4) eLSM are more congruent with experimental values than those derived from SU(3) eLSM. Consequently, we conclude that an increase in quark degrees of freedom significantly enhances the accuracy of meson mass simulations. We investigate the effect of temperature on the masses of various meson states calculated in the SU(3) and SU(4) eLSM. After establishing all the fitting parameters, the temperature dependence of meson masses shows that although various meson states exhibit unique patterns in their mass changes with temperature, they all seem to share a similar range of dissolution temperatures. This means that the critical temperature that marks the phase transition from hadrons to quarks appears to vary slightly depending on the meson states. In this regard, we find that the quarkonium states, formed by a quark and its antiquark, are largely unaffected by variations in the temperature.

Accurate determination of the neutron skin thickness $\left(\mathrm{\Delta }{R}_{\mathrm{np}}\right)$ in finite nuclei is essential for constraining the density dependence of the nuclear symmetry energy. This work presents a systematic investigation of $\mathrm{\Delta }{R}_{\mathrm{np}}$ for the transuranium berkelium (Bk) isotopes within the framework of the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc). The results indicate an overall increase in neutron skin thickness with $N$, which exhibits antikinks at the shell closures $N=184,258$ due to the shell effects. A decomposition of $\mathrm{\Delta }{R}_{\mathrm{np}}$ into volume and surface terms, based on two-parameter Fermi (2pF) fits to angle-averaged DRHBc densities, demonstrates that the volume term dominates as much as $60\%\text{–}70\%$ in most nuclei, consistent with the $65\%$ found in ${}^{208}\mathrm{Pb}$, thereby validating the volume-surface decomposition for deformed nuclei and confirming its correlation with the symmetry energy slope $L$. The surface term prevails only near the proton drip line, where the volume fraction drops below $50\%$ due to the reduced neutron-to-proton ratio. Deformation is found to slightly reduce the central radius $R_c$ but markedly enhance the surface diffuseness $a$, leading to a notable increase in $\mathrm{\Delta }{R}_{\mathrm{np}}$, primarily driven by the surface term. Furthermore, we extend the decomposition to a directional analysis by extracting 2pF parameters along the symmetry axis $(\theta =0^{\circ })$ and perpendicular to it $(\theta ={90}^{\circ })$. In prolate deformed nuclei, a strong directional dependence is observed: although the nucleus is elongated along the symmetry axis, $\mathrm{\Delta }{R}_{\mathrm{np}}$ is significantly larger in the perpendicular direction. This anisotropy is weak for oblate nuclei around the shell closures. The anisotropy of $\mathrm{\Delta }{R}_{\mathrm{np}}$ is attributed mainly to the volume term, which remains the dominant contribution in most nuclei regardless of direction. These findings provide new theoretical insights into the interplay among deformation, the neutron skin thickness, and the symmetry energy, and offer a foundation for future experimental probes of neutron skin anisotropy in heavy-ion collisions.

The cluster structure in light nuclei has been studied by using the extended quantum molecular dynamics model. It is found that the effective number of $\alpha$ clusters in Be, B, C, N, O, and F isotope generally decreases with increasing isospin asymmetry and chain molecular structure exists in non-$\alpha$ conjugate light nuclei from the detailed investigation of the obtained cluster structure. Investigations on the different cluster structures formed in the isotopes ${}^{8,9,10}\mathrm{Be}$, ${}^{9,10}\mathrm{B}$, and ${}^{10}\mathrm{C}$ indicate that the presence of molecular covalent bonds has a significant impact on the properties of cluster structures in light nuclei. These effects include the binding energy and stability, the height and position of the giant dipole resonance (GDR) peak of the $(\alpha +\alpha )$ substructure, and the final-state $\alpha$-particle multiplicity in nuclear reactions induced by these nuclei. There are significant differences in GDR spectra for clusters with different molecular covalent bonds. GDR peak positions decrease as the nucleon-nucleon distance distribution peaks increase, and these peaks are determined by the specific cluster structure. This relationship effectively describes not only the GDR spectral variations for spherical nuclei but also the trends and peak splitting phenomena observed in light nuclei with molecular structures.

High-energy neutron emissions from the reactions of ${}^{40}\mathrm{Ar}$ on natural C, Cu, and Pb targets at $E_{\mathrm{inc}}/A=$ 400 MeV are studied, searching for a possible signature of nucleon-nucleon short-range correlations (SRCs) in the high-energy, high-momentum tails in the neutron spectra. The neutron spectra from the experimental datasets of Y. Iwata et al. [Phys. Rev. C 64, 054609 (2001)] are normalized to the data of R. Madey et al. [Phys. Rev. Lett. 55, 1453 (1985)] above the beam energy per nucleon, using a common reaction of ${}^{20}\mathrm{Ne}$ $+$ Pb at $E_{\mathrm{inc}}/A=400\mathrm{MeV}$ in both datasets, and compared with those of the Semirelativistic antisymmetrized molecular dynamics (SrAMD) with a three-nucleon collision (3NC) term. In the simulations, each nucleon is boosted with Fermi motion (Fermi-boost), and an empirical high-momentum tail (HMT) in the single-nucleon momentum distribution is incorporated, where HMT is closely related to SRCs. The normalized data of Iwata et al. are reasonably well reproduced, including the high-energy, high-momentum tails at forward angles. However, in overall reproduction, the experimental data with the C target are better reproduced with SrAMD-3NC with HMT in the 3NC process, whereas those with the Cu target are better reproduced without HMT. For the Pb target, the experimental data are well reproduced with SrAMD-3NC both with and without that HMT down to the calculated limit of 1 mb ${\mathrm{MeV}}^{-1}$ ${\mathrm{sr}}^{-1}$ with the available computing power. The dispersion of the three different SrAMD simulations becomes smaller as the system size increases. The essential feature of the prediction of SrAMD for the high-energy, high-momentum tails in the neutron spectra is robust and a possible cause for the origin of the different conclusions on the performance of the SrAMD-3NC with and without HMTs on the different targets is suggested to the quality of the experimental data and this prevents us from drawing a conclusive remark about the necessity of HMT in the single-nucleon momentum distribution in nuclei.

The $E1$ component of the $\gamma$-ray strength function of ${}^{72}\mathrm{Ga}$ nuclei has been constrained for the first time through a statistical Hauser-Feshbach analysis of the available capture data for the ${}^{71}\mathrm{Ga}(n,\gamma ){}^{72}\mathrm{Ga}$ reaction over the neutron energy range of 0.01–3 MeV. The analysis employs the nuclear level density (NLD) of ${}^{72}\mathrm{Ga}$ constrained by the work of Santra et al. [Phys. Rev. C 107, 064611 (2023)]. In the present analysis, the Gogny D1M $\mathrm{HFB}+\mathrm{QRPA}$ model is adopted for the $E1$ and $M1$ strength functions, including the low-energy upbend. The normalization of the Gogny D1M $\mathrm{HFB}+\mathrm{QRPA}$ model for the $E1$ component has been constrained in the present work, as a clear minimum is obtained. However, the upbend parameters are not constrained, as no well-defined chi-square (${\chi }^2$) minimum is found for these parameters within physically motivated bounds. The extracted $\gamma$-ray strength function of ${}^{72}\mathrm{Ga}$ is compared with experimental data for the neighboring nuclei ${}^{73,74}\mathrm{Ge}$, exhibiting similar trends. The constrained $\gamma$-ray strength function is then used to calculate the Maxwellian-averaged cross section (MACS) at $kT=30$ keV as a consistency check of the present analysis.

The cross-sections of the $(\gamma ,n)$ reaction of various Cd and Sn isotopes, including the $p$ nuclei ${}^{106,108}\mathrm{Cd}$ and ${}^{112,114}\mathrm{Sn}$, were measured using bremsstrahlung photons of 14 MeV on Cd and Sn targets. The thick-foil activation technique was applied, and the contribution from the $(n,\gamma )$ reaction channel was taken into account. The results are new, providing an effective cross-section for ${}^{106}\mathrm{Cd}(\gamma ,n)$ and ${}^{108}\mathrm{Cd}(\gamma ,n)$ reactions as $42\pm 7$ and $36\pm 5\mathrm{mb}$, respectively. The ${}^{112,114}\mathrm{Sn}(\gamma ,n)$ cross-sections were $34\pm 8$ and $44\pm 11\mathrm{mb}$, and the cross-sections of ${}^{118,124}\mathrm{Sn}(\gamma ,n)$ were measured as $1.1\pm 0.4$ and $42\pm 9\mathrm{mb}$, while the ${}^{114}\mathrm{Cd}(n,\gamma )$ cross-section was $58\pm 9\mathrm{mb}$. The experimental data were compared with talys 2.0 simulations to validate phenomenological and semimicroscopic models, as well as with evaluated data from major nuclear data libraries. The phenomenological SMLO $\gamma$ strength reproduced the experimental cross-sections reasonably well, while the semimicroscopic QRPA strength functions (BSk7, $\mathrm{Skyrme}+\mathrm{HFB}$, D1M) showed comparable predictive capability and, in several cases, a closer agreement with the evaluated data. The $\mathrm{QRPA}+\mathrm{D}1\mathrm{M}$ parametrization, including pion-resonance corrections, yielded the best reproduction of the experimental results, with cross-sections of $41\pm 5$ and $38\pm 5\mathrm{mb}$ for the ${}^{106}\mathrm{Cd}(\gamma ,n)$ and ${}^{108}\mathrm{Cd}(\gamma ,n)$ reactions, respectively. For the Sn isotopes, the calculated values were $38\pm 8\mathrm{mb}$ for ${}^{112}\mathrm{Sn}, 43\pm 7\mathrm{mb}$ for ${}^{114}\mathrm{Sn}$, and $42\pm 9\mathrm{mb}$ for ${}^{124}\mathrm{Sn}$, while for ${}^{118}\mathrm{Sn}$ the ${}^{118}\mathrm{Sn}(\gamma ,n){}^{117m}\mathrm{Sn}$ reaction was found to be much lower ($1.5\pm 0.4\mathrm{mb}$). Effective cross-sections for natural Cd and Sn were deduced as $41\pm 8$ and $43\pm 7\mathrm{mb}$, respectively, at a mean energy of $11\pm 5\mathrm{MeV}$ for ground-state transitions. For isomeric states, the measured cross-sections were about an order of magnitude lower. Overall, the combination of SMLO and D1M-QRPA strength functions with the constant temperature model level density model provides the most consistent description across $(\gamma ,n)$ and $(n,\gamma )$ channels.

The low-lying excitations in odd-odd ${}^{150}\mathrm{Pm}$ have been studied through proton-induced reaction on ${}^{150}\mathrm{Nd}$ with an array of five Compton-suppressed Clover HPGe detectors and one segmented planar Ge detector. The relative excitation functions for the observed $\gamma$ rays have been studied using singles data at two beam energies of 8 and 9 MeV. Sixteen new $\gamma$ rays and 15 new levels have been placed in the level scheme of ${}^{150}\mathrm{Pm}$ based on $\gamma \text{−}\gamma$ coincidence data. The relative intensities for the observed $\gamma$ rays have been determined using total and gated projections. Tentative spin-parity assignments were made for a few low-lying excitations of ${}^{150}\mathrm{Pm}$, using limited angular distribution data and other information. Lifetimes were estimated for two excited levels in this nucleus using generalized centroid difference analysis, applied in the nanosecond range, with Ge detectors. Large-basis shell-model and projected shell-model calculations were performed to interpret the experimentally observed levels. The present work indicates a $1^{-}$ ground state, a $2^{-}$ state close to the ground state $(\approx 50\mathrm{keV})$ and a low-lying $6^{-}$ isomeric state in this odd-odd nucleus along with emerging band structures developed with two quasiparticle configurations.

This work investigates one- and two-neutron transfer in the ${}^{96}\mathrm{Zr}+{}^{40}\mathrm{Ca}$ reaction at sub-barrier energies using a microscopic framework based on time-dependent covariant density functional theory (TD-CDFT). Pairing correlations are incorporated via the time-dependent BCS approximation, which is shown to significantly enhance pair transfer, as evidenced by an increased two-neutron transfer probability. The oblate deformation of ${}^{96}\mathrm{Zr}$ causes the transfer probabilities to vary by orders of magnitude with orientation; a direct comparison with experiment is enabled by averaging results over thirteen systematically chosen orientations. While the orientation-averaged one-neutron transfer probabilities agree well with data, the two-neutron channel is suppressed below the Coulomb barrier. This suppression is attributed to missing quantum fluctuations in the semiclassical TD-CDFT approach. To test this, we employ the generalized time-dependent generator coordinate method, which confirms that quantum fluctuations are essential for an accurate description of sub-barrier two-neutron transfer dynamics.

In this work, we investigate the anisotropic suppression of reconstructed $K^{*0}$ resonances arising from hadronic rescattering using A Multi-Phase Transport (AMPT) model for $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200$ GeV. We demonstrate that the rescattering probability of the decay daughters depends strongly on the decay angle ${\theta }^{*}$ due to Lorentz boost effects, which lead to smaller laboratory-frame momenta for daughters emitted opposite to the parent particle motion. This anisotropic suppression influences several experimentally measured observables. We show that the reconstructed $K^{*0}$ yield exhibits a strong ${\theta }^{*}$ dependence. Furthermore, the anisotropic loss of resonances modifies the angular distributions used to extract the spin alignment parameter ${\rho }_{00}$ in the production-plane and helicity frames. Even in the absence of intrinsic polarization in the model, the reconstructed $K^{*0}$ sample shows deviations of ${\rho }_{00}$ from the unpolarized value of $1/3$, with opposite trends in the two reference frames. These results demonstrate that hadronic rescattering can generate apparent polarization signals and must be carefully considered in experimental measurements of vector-meson spin alignment using production plane and helicity frames.

By generating heavy-ion collision data with the ultrarelativistic quantum molecular dynamics (UrQMD) model, a multiphase transport (AMPT) model, and the JAM model, the impact parameter $b$ in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{\mathrm{NN}}}=4$ and 11 GeV is reconstructed using supervised learning and unsupervised learning in machine learning (ML). In supervised learning, the performance of ML algorithm is cross-checked by using data obtained from these three transport models. It is found that the typical mean absolute error (MAE), which measures the average magnitude of the absolute difference between the true and predicted $b$, is between 0.2–0.4 fm, even when training ML algorithm with data generated from one model but testing with data from others. While the conventional method (i.e., a polynomial fit to multiplicity as a function of $b$) only works for data generated from the same model. In the classification task, the present ML-based method also shows significantly superior results compared to the traditional approach. In unsupervised learning, the $K$-means clustering algorithm is used to partition collision events directly from experimental-style observables, showing that the algorithm autonomously identifies six clusters corresponding to different centrality classes without relying on predefined model-based binning. Our study demonstrates the strong robustness of using an ML algorithm trained on transport-model data for impact-parameter determination, and indicates that this method has the potential to be generalized to handle real experimental data.

We investigate the impacts of intrinsic nuclear deformation and orientation on the yield suppression and momentum anisotropy of charmonia in $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{U}+\mathrm{U}$ collisions at the Relativistic Heavy-Ion Collider (RHIC). The deformed nucleon density is parametrized via a modified Woods-Saxon distribution, which self-consistently determines the initial spatial distributions of both the heavy quarkonia and the bulk medium. A well-established Boltzmann-type transport equation is then utilized to describe the dynamical evolution of charmonia within this anisotropic medium. Using $\mathrm{Au}+\mathrm{Au}$ collisions as a baseline, we find that the momentum-integrated charmonium yield suppression in $\mathrm{U}+\mathrm{U}$ collisions is relatively insensitive to the initial nuclear geometry. In contrast, the elliptic flow ($v_2$) of charmonia is more sensitive to the nuclear deformation, which is inherently driven by specific collision configurations (e.g., tip-tip, body-body-$x$, and body-body-$y$ orientations). These configuration studies elucidate how the spatial orientation of deformed nuclei relative to the impact parameter dictates the initial geometric eccentricity, which subsequently translates into the final-state momentum anisotropy of charmonia. Notably, this orientation-induced effect is enhanced for the excited $\psi \left(2S\right)$ state, as its larger dissociation rate amplifies the azimuthal asymmetry in the path-integrated survival probability.

We employ physics-informed neural networks (PINNs) to investigate the dynamical evolution of heavy quarks within the expanding hot QCD medium generated in relativistic heavy-ion collisions. The heavy quark dynamics are first modeled under the assumption of complete kinetic thermalization, followed by a more realistic study of nonthermal diffusion governed by the Fokker-Planck (FP) equation. In both scenarios, the background evolution of the hot QCD medium is encoded into the coefficients of the diffusion equations. These equations are solved within the PINN framework, where the initial conditions, physical constraints from the dynamical equation, and probability conservation are incorporated into the loss function. We also compare the performance of the FP-PINN with a supervised five-dimensional DNN trained on labeled data generated from Langevin-based reference distributions. This work provides a valuable reference for applying PINN-based models to particle diffusion in phase space, laying the foundation for future studies of heavy quarkonium production via realistic nonthermal heavy quark coalescence.

We present the yield, average transverse momentum, and collective flow calculations of $K^{*0}$ resonances in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=19.6$, 14.5, and 7.7 GeV using the AMPT model. It is found that, due to hadronic rescattering, the decay daughters of $K^{*0}$ interact with other particles in the medium, causing the yield of reconstructable $K^{*0}$ to be significantly suppressed, especially at low transverse momentum. The model results are compared with recent experimental data from Phase-II of the Beam Energy Scan (BES-II) program at the Relativistic Heavy-Ion Collider. The string-melting version of the AMPT model successfully reproduces the measured $K^{*0}/K$ ratios at all three analyzed collision energies. Interestingly, AMPT calculations that exclude the hadronic phase nevertheless provide a reasonable description of the data, thereby challenging the conventional interpretation that hadronic rescattering is the primary mechanism responsible for suppressing the $K^{*0}/K$ ratio in central heavy-ion collisions. In addition, we find that the $K^{*0}/K$ ratio appears to be largely insensitive to the lifetime of the hadronic phase, whereas the average transverse momentum, $\langle p_T\rangle$, of the $K^{*0}$ shows a strong dependence, increasing significantly as the lifetime of the hadronic phase becomes longer. We further show that the directed flow $\left(v_1\right)$ of $K^{*0}$ mesons is strongly influenced by hadronic rescattering, whereas the elliptic flow $\left(v_2\right)$ exhibits only weak sensitivity to hadronic effects. These results establish $K^{*0}$ directed flow as a sensitive probe of the late-stage hadronic medium in heavy-ion collisions. These model calculations therefore provide valuable insight into the underlying physics governing the observed experimental results at RHIC.

In this work, we have extracted the nuclear level density (NLD) and $\gamma$-ray strength function ($\gamma \mathrm{SF}$) using the Oslo method on particle-$\gamma$ coincidence data from the ${}^{90}\mathrm{Zr}(p,p^{\prime }\gamma ){}^{90}\mathrm{Zr}$ reaction. We have applied the shape method to the same data set, providing a model-independent $\gamma \mathrm{SF}$ and a cross-check on the slope of the Oslo-method NLD and $\gamma \mathrm{SF}$. Further, we have combined the $\gamma \mathrm{SF}$ from this work with photonuclear data, thus covering the $2.5<E_{\gamma }<18\mathrm{MeV}$ energy range. We see an increase in strength in the region around $E_{\gamma }\approx 9\mathrm{MeV}$, consistent with previous $(\gamma ,{\gamma }^{\prime })$ and $(\gamma ,n)$ data. On the other hand, surprisingly, we do not observe a strong low-energy increase at low transition energies. The resulting NLD and $\gamma \mathrm{SF}$ were used as inputs to the nuclear reaction code talys to estimate the cross sections and astrophysical reaction rates for the ${}^{89}\mathrm{Zr}(n,\gamma ){}^{90}\mathrm{Zr}$ and ${}^{89}\mathrm{Y}(p,\gamma ){}^{90}\mathrm{Zr}$ reactions. We find good agreement with available experimental cross sections and JINA calculations for the ${}^{89}\mathrm{Y}(p,\gamma )$ results, but not for the ${}^{89}\mathrm{Zr}(n,\gamma )$ reaction rate for stellar temperatures above 0.7 GK. Based on our data, we provide a much more narrow uncertainty band for the ${}^{89}\mathrm{Zr}(n,\gamma )$ cross section and reaction rate.

We have developed a systematic approach to calculate the correlation function for spin-1/2 particles, incorporating both central and noncentral components of the interparticle interaction. This is achieved by extending the variable phase method to accommodate noncentral potentials and numerically solving the Schrödinger equation. Within this framework, the partial-wave contributions to the nucleon-nucleon correlation functions adopting the Reid soft-core potential are evaluated. The resulting correlation functions are then compared for Gaussian sources of different sizes.