Systematic calculations of $\alpha$-decay and spontaneous-fission (SF) properties are presented for the even-even superheavy isotopic chains with $Z=120–130$. The $\alpha$-decay half-lives are evaluated within the density-dependent cluster model using a double-folding potential with a zero-range exchange approximation (DFM-ZR), employing the WS4 $Q_{\alpha }$ values and deformation parameters $({\beta }_2,{\beta }_4)$ as inputs. The microscopic results are compared with the BKAG, UDL, NRDX, Horoi, and Ren A empirical formulas for both spherical and deformed daughter-nucleus configurations. To quantify the agreement between the microscopic and empirical predictions, the root-mean-square deviation, mean absolute deviation, and maximum absolute deviation of ${log}_{10}{T}_{1/2}$ are evaluated for each isotopic chain. The calculations show that nuclear deformation has a significant influence on the $\alpha$-decay systematics, particularly in the heavier chains where the daughter nuclei develop stronger prolate shapes. The DFM-ZR predictions exhibit trends similar to those of the BKAG, NRDX, Horoi, and Ren A formulas, whereas the UDL formula yields systematically shorter half-lives and larger deviations from the microscopic results. The predicted systematics further indicate a structural evolution from weakly deformed nuclei near the vicinity of the $N=184$ shell closure to more pronounced prolate deformations at higher $Z$. Local irregularities around $N_d\approx 194$ in the $Q_{\alpha }, S_{\alpha }$, and half-life trends suggest a possible deformed subshell effect, although a more detailed shell-structure analysis would be required to confirm this interpretation. Comparison with the SF half-lives shows that spontaneous fission becomes increasingly competitive with increasing proton number and is predicted to dominate for many nuclei with $Z\ge 126$, whereas the $Z=120–124$ chains remain more favorable candidates for observable $\alpha$ decay. These results provide a consistent theoretical framework and useful guidance for future searches for superheavy nuclei beyond the presently known limit of the nuclear chart.

Starting from a chiral two- plus three-nucleon interaction, we perform a systematic study of the low-lying states of neutron-rich nuclei around $N=20$ using the in-medium generator coordinate method, which combines the multireference in-medium similarity renormalization group with the quantum-number projected generator coordinate method defined in a full single-particle space. The main features of the energy spectra and electromagnetic properties of low-lying states in both even-even and odd-mass nuclei of this mass region are reasonably reproduced. The boundary of the $N=20$ island of inversion (IOI) is investigated, and the results indicate that ${}^{30}\mathrm{Ne}, {}^{29,31,33}\mathrm{Na}, {}^{31,32,33,34}\mathrm{Mg}$, and ${}^{35}\mathrm{Al}$ lie within the IOI, whereas ${}^{29}\mathrm{F}, {}^{29}\mathrm{Ne}, {}^{30}\mathrm{Mg}, {}^{31,33}\mathrm{Al}, {}^{34,35}\mathrm{Si}$, and ${}^{35}\mathrm{P}$ fall outside it.

A simple pattern of organization, the nuclear shell structure, emerges from the complex interactions between nucleons in nuclei and determines, to some significant degree, nuclear structure properties. Recent experimental investigations of exotic nuclei revealed a shortfall in our current understanding of nuclear shell evolution and nuclear magicity. We introduce a novel perspective in the Energy Density Functional framework, where the Dirac mass kinetic term, which stems from the singular participation of a spin-0 boson in the nuclear strong force, plays a pivotal role in generating the nuclear shell structure. Namely, the combination of the Dirac mass kinetic term with the spin-orbit term redefines magic numbers in both stable and exotic nuclei. The identification of this mechanism enables a broad understanding of the origin and evolution of nuclear magic numbers.

The relativistic wave functions of ${}^3\mathrm{He}$ and ${}^3\mathrm{H}$ nuclei are calculated in the framework of light-front dynamics. They are determined by 32 spin-isospin components, each of which depends on five scalar variables. For nucleon-nucleon interaction, the one-boson exchange model is assumed but without a potential approximation. The relativistic effects manifest themselves in deviation of the relativistic components from the nonrelativistic input, in the appearance of the components absent in the nonrelativistic limit, and in dependence of solutions on specific variables that do not exist in the nonrelativistic wave function.

Nuclear mass prediction is one of the core issues in nuclear physics research, yet it faces the challenge of small-sample datasets with high complexity. This study introduces the Kolmogorov-Arnold network (KAN) into the refinement of nuclear mass models, proposing an efficient and interpretable solution. By constructing the KAN-WS4 hybrid model, the prediction accuracy is significantly improved (the root-mean-square error is reduced from 0.3 MeV to 0.16 MeV). Furthermore, leveraging the intrinsic interpretability of KAN, feature-importance analysis reveals that the proton number is the most critical factor influencing residuals, indicating potential systematic biases in proton-related terms within existing theoretical models. The method's generality is demonstrated across five mass models. This study shows that KAN provides a novel approach to small-sample, high-complexity scientific problems. Its interpretability facilitates the data-driven discovery of physical laws, promising broad applicability to key nuclear physics issues.

Neutron-deficient nuclei in the $N\approx Z, A\approx 90$ region were produced by fragmentation of a relativistic ${}^{107}\mathrm{Ag}$ beam at the GSI Helmholtz Centre for Heavy Ion Research (GSI), separated in the fragment separator FRS, slowed down, and thermalized, and high-precision mass measurements were performed employing the multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) of the FRS Ion Catcher. The masses of ${}^{91,93,95}\mathrm{Rh}, {}^{89}\mathrm{Ru}, {}^{88}\mathrm{Tc}, {}^{87,88,89}\mathrm{Mo}$, and ${}^{87,88,89}\mathrm{Nb}$ were determined. The mass of ${}^{91}\mathrm{Rh}$ was measured for the first time. For ${}^{89}\mathrm{Ru}$, the measured mass excess deviates by more than ten standard deviations (361 keV) from the previous measurement. A possible misidentification of the measured nuclei, including ${}^{89}\mathrm{Ru}$, with contaminants was excluded using a newly developed identification technique for MR-TOF-MS measurements. For the other nuclides, the measured masses agree well with previous measurements. The impact of the new masses on the one-proton separation energy ($S_p$) of the nuclei with constant total isospin projection ($T_z$) in the island of inversion around $N=Z=40$ is investigated, and signatures of the deformed shell gap at $Z=38$ are found. A comparison of the experimental $S_p$ values with the predictions of several mass models shows a general agreement of the trends.

Within the isospin-dependent quantum molecular-dynamics (IQMD) framework, we investigate the multiplicity information entropy $H$ of neutrons, protons, intermediate-mass fragments (IMFs), and all fragments, together with the $\mathrm{\Delta }$-scaling behaviors, in central ${}^{197}\mathrm{Au}+{}^{197}\mathrm{Au}$ collisions over an incident energy range of $E=20–350\mathrm{MeV}/\mathrm{nucleon}$. The information entropy of IMFs exhibits a plateau around $E=110$ MeV/nucleon, while that of all fragments shows a pronounced turning point at a similar energy. When considered together with other observables, these features reflect a correlated change in fragment production dynamics in this energy region. In contrast, the $\mathrm{\Delta }$-scaling analysis of the largest fragment charge $Z_{\max }$ does not indicate a transition from $\mathrm{\Delta }=1/2$ to $\mathrm{\Delta }=1$ over the same energy range. However, the charged-fragment multiplicity exhibits distinct $\mathrm{\Delta }$-scaling behaviors in low- $(E=20–80\mathrm{MeV}/\mathrm{nucleon})$ and high-energy $(E=100–350\mathrm{MeV}/\mathrm{nucleon})$ regions. These combined observations suggest that the multiplicity information entropy and the $\mathrm{\Delta }$-scaling behavior of charged fragments consistently reflect a coherent change in the fragmentation dynamics around $E=110$ MeV/nucleon.

A negative muon captured by an actinide cascades down through the muonic atomic levels; deeply bound transitions can proceed via inverse internal conversion, depositing the muonic transition energy directly into the nucleus and, when the deposited energy exceeds the fission barrier, inducing prompt fission. Because the muon mean lifetime exceeds the saddle-to-scission timescale by orders of magnitude, the muon can survive the entire fission event as a $1s$ spectator and ultimately attach to one or both of the emerging fragments. Its postscission attachment probability to the light fragment, $P_L$, can be used as a direct electromagnetic probe of fission dynamics on a timescale of ${10}^{-21}\mathrm{s}$. In previous work, we introduced a three-dimensional lattice solution of the time-dependent Dirac equation coupled to the electromagnetic field generated by a fissioning nucleus and reported $P_L$ for several actinides at a single dissipation strength. Here we extend that framework to a systematic survey of ${}^{232}\mathrm{Th}, {}^{238}\mathrm{U}$, and ${}^{240}\mathrm{Pu}$ and implement a more realistic fission model which incorporates dynamic pairing correlations. We find that $P_L$ falls steeply with the fragment charge asymmetry, a robust structural fingerprint of the fissioning system, while its dependence on nuclear dissipation is secondary and sensitive to the phenomenological friction prescription. These results establish $P_L$ as a clean electromagnetic probe of fragment charge asymmetry and motivate a self-consistent, coordinate- and time-dependent treatment of nuclear dissipation as the natural next step.

Platinum radioisotopes are of growing interest for targeted cancer therapy and diagnostic imaging because their decay delivers highly localized radiation doses in tissue, herewith enabling precise DNA damage through Auger-electron emission. Developing production technologies that provide platinum isotopes with high specific activity is essential in radioisotope therapy. Photonuclear reactions on stable nuclei offer a viable accelerator-based route for isotope production when supported by reliable cross-section data. We report photonuclear cross-section measurements for the ${}^{197}\mathrm{Au}(\gamma ,pn){}^{195m}\mathrm{Pt}$ reaction at incident $\gamma$-ray energies of 27, 29, and 31 MeV using the activation method. The measurements were performed by irradiating a stack of concentric-ring gold targets with a quasimonoenergetic $\gamma$-ray beam provided by the High Intensity Gamma-ray Source ($\mathrm{HI}\gamma \mathrm{S}$). The induced ${}^{195m}\mathrm{Pt}$ activity was quantified using offline $\gamma$-ray spectroscopy. These data provide the first experimental constraints on the ${}^{197}\mathrm{Au}(\gamma ,pn){}^{195m}\mathrm{Pt}$ cross section in the near-threshold region. The comparison of the measured excitation function to phits and talys calculations indicates that the reaction becomes measurable only near 30 MeV and that substantially higher bremsstrahlung end-point energies are required for practically meaningful production.

At the keV-scale energies of stellar nucleosynthesis, the resonant charged-particle reactions addressed by the Trojan-horse method (THM) proceed through isolated near-threshold resonances, so the low-energy cross section and the resonance strength carry the same information. The standard THM working formula is used there as a fixed extraction prescription, without a controlled reduction from the inclusive nonelastic breakup parent that would identify what it sets aside. I derive the sub-Coulomb resonant THM extraction directly from the Ichimura-Austern-Vincent inclusive nonelastic breakup cross section. A diagonal isolated-pole spectral ansatz for the absorptive participant-target potential, with four explicit validity conditions, reduces the inclusive cross section in the isolated-resonance limit to a per-pole distorted-wave Born approximation cross section on the resonance state, retaining full distortions and the postform interaction and weighted by the channel branching ratio; this is the operational quantity for resonance-strength extraction. The same one-level total-width profile follows independently from the postform transfer amplitude through the exact final states, so the extraction is route independent; a three-layer width analysis fixes its absorptive strength as half the nonelastic decay width, resolving the width and sign ambiguities of the literature. The standard factorized THM formula then follows under three dynamical approximations, plane waves, on-shell binary amplitude, and remnant neglect, together with a zero-range simplification of the projectile vertex, making explicit what it sets aside: the partial-wave coherence and the postform remnant.

We study the sensitivity of anisotropic flow in $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{s_{NN}}=5.02$ TeV to the neutron skin of ${}^{208}\mathrm{Pb}$ using the improved string-melting version of a multiphase transport (AMPT) Model. By varying the neutron surface diffuseness, we trace the impact of several neutron-skin scenarios from the initial nuclear density profiles and eccentricities to final-state charged-particle production and flow cumulants. A systematic response is observed in both the initial eccentricities and the anisotropic flow, indicating that the neutron-skin-induced geometric effects can survive the full transport evolution. A model-to-data comparison with ALICE measurements disfavors the most compact and most diffuse density profiles within the tested AMPT setup, while the reference and moderate-skin configurations give comparable descriptions. Their similarity reflects a geometric degeneracy in large $\mathrm{Pb}+\mathrm{Pb}$ collision systems, where the inclusive anisotropic flow is dominated by the effective collision geometry and nuclear size, making it only weakly sensitive to the detailed structure of the neutron surface. These results clarify both the sensitivity and the limitations of using anisotropic flow in relativistic heavy-ion collisions to probe neutron-skin effects.

We present an upgraded formula for Wigner function and spin polarization of fermions emitted by a relativistic fluid at local thermodynamic equilibrium at the decoupling, which improves the one obtained by F. Becattini, M. Buzzegoli, and A. Palermo [Phys. Lett. B 820, 136519 (2021)] and by S. Y. F. Liu and Y. Yin [J. High Energy Phys. 07 (2021) 188] that is used in numerical simulations of relativistic nuclear collisions. By using a new expansion method, applicable to decoupling hypersurfaces with arbitrary geometry, we reproduce the known term proportional to thermal vorticity and obtain an upgraded form of the spin-shear term which captures the dependence on the geometry. The new method also includes additional contributions whose physical nature is to be assessed. The new expression also naturally excludes contributions from space-time gradients in the normal direction of the hypersurface, providing a theoretical justification for the isothermal condition previously imposed a priori. This framework can be extended to particles with arbitrary spin.

The simultaneous observation of strong sequential bottomonium suppression and small azimuthal anisotropy constrains the time scale and geometry of quarkonium dissociation in relativistic heavy-ion collisions. This work investigates an early-time contribution in which strong pre-equilibrium color fields generate an effective proper-acceleration scale and an associated causal length. The maximal acceleration is fixed through the phenomenological anchoring assumption $T_U^{max}\simeq T_c$, without identifying the kinematic Unruh scale with an equilibrium temperature. The survival probability is described by an event-averaged one-scale exponential ansatz. With no state-by-state adjustment, the resulting horizon component gives a quantitatively reasonable description of the LHC centrality dependence. For the directly measured $\mathrm{{\rm Y}}\left(2S\right)$-to-$\mathrm{{\rm Y}}\left(1S\right)$ double ratio, the fixed horizon term supplies a substantial part of the relative suppression, while the data require an additional state-dependent late-stage factor. A minimal one-parameter effective quark-gluon plasma (QGP) attenuation gives a quantitative multistage description. At RHIC, the absolute $R_{AA}$ central values lie below the isolated horizon component, while the relative $2S$-to-$1S$ suppression remains compatible with the predicted state-size hierarchy within present uncertainties. Because the proposed early factor is local and scalar, it gives the exact leading-order null contribution $v_2^H=0$ within this construction, consistent with current CMS measurements.

Relativistic ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ collisions provide a valuable opportunity to study both the quark-gluon plasma formed in small systems and the intrinsic structure of ${}^{16}\mathrm{O}$. Recent implementations of ab initio nuclear configurations in heavy-ion simulations have produced different predictions for cluster-sensitive observables, making it difficult to identify the origin of possible $\alpha$-cluster signals. In this work, we introduce a controlled sampling scheme that varies the compactness of $\alpha$-cluster-induced multinucleon correlations while keeping the one-body density distribution of ${}^{16}\mathrm{O}$ fixed. This allows us to separate effects driven by the tetrahedral one-body density from those driven by genuine multinucleon correlations. We show that the normalized ratios $\mathrm{Norm}(v_2\left\{2\right\}/v_2\left\{4\right\})$ and $\mathrm{Norm}(v_2\left\{2\right\}/v_3\left\{2\right\})$, together with their initial-state eccentricity counterparts, provide complementary constraints on initial-condition model dependence and cluster compactness. Hybrid hydrodynamic simulations and comparisons with recent LHC measurements further clarify the extent to which the initial-state signals survive final-state evolution. Our results provide a framework for using relativistic light-ion collisions to constrain cluster correlations in ${}^{16}\mathrm{O}$.

We present a new formulation for the mean-field propagation part of relativistic quantum molecular dynamics, simulating an $N$-body system of interacting Gaussian wave packets via Lorentz scalar and vector potentials. Covariant equations of motion are derived based on the principle of least action with a weak form of mass-shell conditions and time-fixation constraints defined with respect to a chosen foliation. However, as is common with traditional relativistic quantum molecular dynamics, the dynamics exhibits a residual dependence on the chosen foliation, which is unavoidable because a finite number of interacting degrees of freedom is not strictly compatible with relativity. Nevertheless, we show that this dependence remains small for physically reasonable choices of the foliation in practical applications. By introducing a new approximation method to the spatial integral in the equations of motion, these covariant equations of motion can be solved with a computational cost comparable to that of conventional noncovariant quantum molecular dynamics. Furthermore, the new equations of motion accurately estimate the density-dependent potential, as demonstrated through comparison of the forces with the numerical integration. We apply them to $N$-body systems interacting via the Skyrme-type potentials or the relativistic mean field to simulate heavy-ion collisions. Our results show that the derived equations of motion provide a robust approximation to the dynamics of the full numerical integrations.

The correlation between vorticity and spin alignment in heavy-ion collisions can be probed through polarization measurements of hadrons, whose total spin originates from both constituent-quark spins and orbital angular momentum in the quark-model framework. So far, experimental measurements have been limited to $\mathrm{\Lambda }$ baryons and vector mesons, whose total spins are composed of quark spins in $s$-wave states within the quark model. Here, as a means to probe the vorticity structure in heavy-ion collisions, we highlight the importance of studying hadrons whose total spin is composed not only of quark spins but also includes contributions from the orbital angular momentum between quarks. To motivate such experimental studies, we calculate the general angular distribution of produced pion in $f_2\left(1270\right)\to \pi +\pi$ using interaction Lagrangian and helicity formalism and check that both methods yield the same result. The distribution is given as a function of angle between pion and initial quantization axis of $f_2$ and the spin-density matrix element of $f_2$. Its diagonal entries and ${\rho }_{20}$ component were computed assuming local thermal equilibrium and blast-wave model for different centrality classes, hence given as a function of azimuthal angle with respect to the impact parameter. This is to set a baseline for future comparison with experiment, as vorticity and spin will, in general, not be in equilibrium.

In this work, we discuss the $\gamma W$-exchange contributions in neutron $\beta$ decay with an elastic intermediate state, beyond the forward-angle limit (FAL). By decomposing the one-$W$-exchange and $\gamma W$-exchange amplitudes in terms of 16 independent Pauli-spinor structures, we calculate the $\gamma W$-exchange corrections to the relevant coefficients. Our numerical results show that the relative corrections to the Fermi Born term $C_{\text{Born}}^{\text{F}}$ and the Gamow-Teller Born term $C_{\text{Born}}^{\text{GT}}$ are enhanced by about 8% and 18%, respectively. In particular, we find a nonzero contribution to $C_{\text{Born}}^{\text{GT}}$ from the axial-vector current, which is identically zero in the FAL. The corresponding effect on the extracted $V_{ud}$ from the neutron lifetime is also analyzed, and we find the correction to be at the ${10}^{-4}$ level.

The astrophysical $S^{*}\left(E\right)$ factor for the ${}^{12}\mathrm{C}+{}^{12}\mathrm{C}$ reaction within the Gamow window ($E_G=1.5\pm 0.3$ MeV) plays a pivotal role in modeling stellar carbon burning and explosive nucleosynthesis scenarios. However, direct measurements—or even simple extrapolations—at these energies are severely hindered by Coulomb suppression and the possible presence of narrow resonances. To address this challenge, we performed an indirect measurement of the ${}^{12}\mathrm{C}({}^{16}\mathrm{O},\alpha \mathit{p}){}^{23}\mathrm{Na}$ reaction at the HI-13 Tandem Accelerator, employing ${}^{16}\mathrm{O}=({}^{12}\mathrm{C}\oplus \alpha )$ as the Trojan horse nucleus. A key innovation of this Trojan horse method (THM) study is the implementation of a copper beam-stopper foil, which enabled the detection of spectator particles near $0^{\circ }$ –the angular region where their yield is maximized under quasi-free kinematics. The $S^{*}\left(E\right)$ factor for the ${}^{12}\mathrm{C}({}^{12}\mathrm{C},\mathit{p}){}^{23}\mathrm{Na}$ reaction in the astrophysically relevant energy range was extracted using the THM formalism based on the distorted-wave Born approximation (DWBA). Our results confirm the presence of resonant structures within the Gamow window around 1.5 MeV in both the $p_0$ and $p_1$ proton channels. No evidence of a hindrance effect is observed in the measured energy range. Without considering the resonance details, the overall trend of our results is qualitatively in reasonable agreement with the THM-Tumino2018 and TTIK2025 data, but differs significantly from the trend of the Modified-THM-Muk2019 data.

We investigate neutron star matter with hyperons within a density-dependent relativistic mean-field framework using Bayesian inference, considering three composition scenarios: purely nucleonic matter, hyperonic matter under SU(6) flavor symmetry, and hyperonic matter under SU(3) symmetry with free vector-sector parameters. The analysis incorporates constraints from empirical nuclear matter properties, theoretical inputs at low densities, and multimessenger observations of neutron stars. We find that the SU(6) scheme, grounded in the quark model and isospin counting rule, leads to a significantly softer equation of state. In contrast, the additional flexibility of the SU(3) framework enhances vector repulsion and yields a comparatively stiffer equation of state consistent with observational bounds across the explored parameter space; in particular, the posterior distributions favor values of the vector coupling ratio ${\alpha }_v$ lower than the SU(6) limit ${\alpha }_v=1$. These differences are reflected in neutron star observables, including mass-radius relations, tidal deformabilities, direct Urca thresholds, and oscillation properties, all of which remain compatible with current constraints within the SU(3) scenario. We further examine structural signatures through the curvature of the mass-radius relation and find that, although hyperon-rich configurations can induce noticeable variations, such features depend sensitively on the stiffness of the equation of state and are therefore not universally robust indicators. Bayesian model comparison further shows that present constraints do not meaningfully discriminate between the purely nucleonic and SU(3) hyperonic scenarios, while providing positive, but not decisive, evidence against the more restrictive SU(6) framework.