Quantifying causal connections within fireballs resulting from high energy nucleus-nucleus collisions is pertinent to assessing the viability of several proposed mechanisms that directly influence particle production and correlations. Fireball causal connections have previously been studied in the context of $1+1$ dimensional Bjorken flow. We expand into $3+1$ dimensions using Gubser flow, which includes transverse expansion. Our findings suggest that the volume of these causally connected fireballs are on the order of 10–100 ${\mathrm{fm}}^3$ for observables dependent on the formation of the light quark condensates, but could be larger for other observables.

We investigate the internal structure of two exotic tetraquark candidates, ${\chi }_{c1}\left(3872\right)$ and $T_{cc}^{+}\left(3875\right)$, whose masses lie within $1\text{MeV}$ of the $D^0{\overline{D}}^{*0}$ and $D^0{D}^{*+}$ thresholds, respectively. Using the effective-range expansion (ERE) supplemented by resonance compositeness relations on the second Riemann sheet, we extract scattering lengths $a$ and effective ranges $r$ directly from the experimental masses and widths and quantify the $D{D}^{*}$ molecular content through partial compositeness coefficients $X_j$. A two-channel framework couples each state's inelastic detection channel ($J/\psi \pi \pi$; $D^0{D}^0{\pi }^{+}$) to the near-threshold molecular channel. Full Monte Carlo uncertainty propagation with $N=50000$ Gaussian samples yields asymmetric $68\%$ confidence intervals for all observables. We find large negative scattering lengths $a=-8.{49}_{-1.05}^{+0.93}$ fm for ${\chi }_{c1}\left(3872\right)$ and $a=-14.{57}_{-1.66}^{+1.70}$ fm for $T_{cc}^{+}$, both far exceeding the natural hadronic scale $\approx 1/m_{\pi }$ and dominant molecular components $X_2>0.95$ under full compositeness. The results are stable for total compositeness $X\in [0.5,1.0]$, where $1-X$ represents an upper bound on any compact/CDD-pole contribution. In the present study, we go beyond the pole-position Castillejo-Dalitz-Dyson (CDD) criterion by explicitly constructing the inverse amplitude as an ERE background plus a scanned CDD pole term, finding no region of physically reasonable bare-state parameter space that reproduces the pole while leaving a natural background; we fully propagate the loop-function subtraction constant $a\left({\mu }_g\right)$ as a Monte Carlo nuisance parameter jointly with the experimental mass and width, confirming it contributes a negligible ($<0.01\%$) additional uncertainty; and we test robustness against an assumed correlation between $M_R$ and ${\mathrm{\Gamma }}_R$, finding all results stable over a broad range of correlation coefficients. We demonstrate analytically and numerically the scheme-independence of the compositeness coefficients, provide explicit derivations of all ERE formulas from the pole condition, clarify the analytic continuation procedure for closed channels, and compare our results quantitatively with independent ERE, effective-field theory, and other relevant studies. The $Z_c\left(3900\right)$ case is treated separately to show the breakdown of the two-channel approximation for above-threshold states. Graphical illustrations of the Monte Carlo distributions are included.

We investigate the interaction dependence of the liquid-gas critical point of symmetric nuclear matter in finite-temperature lattice effective field theory. Building on the pinhole-trace algorithm, we benchmark a first-order perturbative treatment for representative Hamiltonian splittings and then compute the finite-temperature equation of state for a sequence of sign-friendly lattice Hamiltonians ranging from an SU(4)-symmetric interaction to Hamiltonians with physical ${}^{1}S_0$ and ${}^{3}S_1$ channel dependence and three improved leading-order Hamiltonians. The finite-temperature analysis is complemented by zero-temperature calculations of the symmetric-matter saturation point and the binding energies of selected nuclei within the same lattice framework. We find that the benchmarked perturbative strategy is quantitatively reliable in the thermodynamic regime studied. Across this Hamiltonian sequence, the leading order Hamiltonians improve the overall description of finite-nucleus binding energies and move the zero-temperature saturation point toward the empirical region, while lowering the critical temperature from 15.33(6) to $13.50\left(17\right)–13.71\left(19\right)$ MeV. These calculations show that finite-temperature criticality is not fixed by zero-temperature saturation and binding alone, and they provide a complementary benchmark for future lattice interaction development.

Based on the liquid-drop model, we propose and refine a local formula for the released energy of proton radioactivity $\left(Q_{\mathrm{p}}\right)$. The calculated results for 44 proton emitters with 71 $\le Z\le$ 91 are in good agreement with the experimental data. For comparison, the WS4 [Phys. Lett. B 734, 215 (2014)] and FRDM [At. Data Nucl. Data Tables 125, 1 (2019)] nuclear mass models are also employed. The root-mean-square (rms) deviations between the experimental data and theoretical results obtained from this work, WS4, and FRDM are 0.071 MeV, 0.144 MeV, and 0.348 MeV, respectively. These results demonstrate that the present approach reproduces the experimental $Q_{\mathrm{p}}$ values well in the considered region. The formula is further employed to predict the released energies for candidate proton emitters, and the predictions are broadly consistent with those of the other models.

We analyze the $\gamma p\to K^0{\mathrm{\Sigma }}^{+}$ process in the resonance region within the framework of the isobar model. The amplitude is constructed as a sum of tree-level Feynman diagrams with the addition of the contact current ensuring gauge invariance of the total amplitude. The resonance content of our models is inspired by a model for the isospin-related $K^{+}{\mathrm{\Sigma }}^0$ channel. The main coupling constant in the $K\mathrm{\Sigma }N$ vertex is estimated with the help of isospin symmetry, and the rest of the free parameters (resonance couplings and hadronic form-factor cutoffs) are calibrated to the available $K^0{\mathrm{\Sigma }}^{+}$ data. Using the resulting models, we calculate the differential and total cross sections as well as polarization observables $(P$, $\mathrm{\Sigma }$, $T$, $O_x$, $O_z)$, and compare them with measurements. We identify the $N\left(1720\right)3/2^{+}$ and $N\left(1900\right)3/2^{+}$ states as the most important ones for good correspondence with the experimental data.

We present a field-theoretical description of the deuteron electrodisintegration reaction $d(e,e^{\prime }p)n$ induced by unpolarized and polarized electrons. The approach combines the Lehmann-Symanzik-Zimmermann $\text{in}\left(\text{out}\right)$ formalism with the clothed particle representation in the instant form of relativistic dynamics, providing a fully relativistic and gauge-independent framework based on the Fock-Weyl criterion. Within the method of unitary clothing transformations, one and the same transformation that generates the relativistic nucleon-nucleon interaction (the Kharkiv potential) also induces a fresh family of electromagnetic current operators. As a result, one-body and two-body (meson-exchange) currents emerge on a common footing. We compute differential cross sections and polarization observables with the inclusion of final-state interaction effects and meson-exchange current contributions and compare the results with Saclay and Jefferson Lab data as well as with earlier theoretical predictions. The role of relativistic ingredients (one- and two-body currents, Fermi-motion effects, etc.) and the interplay between them are analyzed in several kinematic regimes of the experiments at Saclay and Jefferson Lab.

Background: In any theoretical framework for nuclear structure, the quantitative description of $E0$ transition rates remains a nontrivial and persistent challenge. Moreover, these observables impose stringent constraints on the viable parameter space of such models.

Purpose: This work aims to systematically investigate the behavior of selected ${\rho }^2\left(E0\right)$ values and their ratios across the entire parameter space of the interacting boson model with a single configuration. As a concrete application, the even-even Xe isotopic chain is analyzed in detail.

Method: The interacting boson model will be employed to calculate ${\rho }^2\left(E0\right)$ values for selected key transitions and to investigate the evolution of these observables across the parameter space of the model.

Results: Several key ${\rho }^2\left(E0\right)$ quantities, either absolute values or ratios, are analyzed, and contour plots are generated within the parameter space of the interacting boson model, represented by the Casten triangle. The calculated results for even-even Xe isotopes are then mapped onto and compared with these contour plots.

Conclusions: The present analysis demonstrates that the ${\rho }^2\left(E0\right)$ values, and in particular specific ratios, provide stringent constraints on the parameter space of the interacting boson model. Furthermore, there exist regions of this parameter space in which the ${\rho }^2\left(E0\right)$ values are effectively invariant under fine tuning of the Hamiltonian parameters and, hence ${\rho }^2\left(E0\right)$ cannot be used to constrain the parameters.

We predict the $\eta /{\pi }^0$ ratio at low $p_T$ ($p_T\lesssim 3\mathrm{GeV}/c$) using the measured charged $K/\pi$ ratio and model input from a blast-wave framework with feed-down contributions. This approach can provide improved, data-constrained background estimates for direct-photon and dilepton measurements in heavy-ion collisions. In this approach, the explicit modeling of radial flow and hadronic feed down enables an uncertainty estimate for the low-$p_T$ extrapolation of the $\eta /{\pi }^0$ ratio. Using central Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV as an example, we find that the $\eta$-related decay-photon uncertainty at $p_T\approx 1\mathrm{GeV}/c$ is of order 10% of the expected direct-photon signal.

We apply a constituent quark equal-velocity combination (EVC) model to study the elliptic flow ($v_2$) and triangular flow ($v_3$) of light-flavor and single-charmed hadrons in Pb+Pb collisions at $\sqrt{s_{NN}}=$ 2.76 and 5.02 TeV. $v_{2,3}$ of hadrons in the EVC model can be expressed as a linear superposition of the $v_{2,3}$ of quarks at the same velocity as that of the hadrons. We find that available experimental data for $v_2$ and $v_3$ of $p, \mathrm{\Lambda }, \mathrm{\Xi }$, and $\mathrm{\Omega }$ as a function of transverse momentum ($p_T$) can be consistently explained by the EVC formula using the $v_2$ of up/down quarks and the $v_2$ of strange quarks. In comparison with $v_2$ data of $\varphi$ at $\sqrt{s_{NN}}=2.76$ TeV, which can be naturally explained by the $v_2$ of strange quarks, explanation of the data of $\varphi$ mesons at $\sqrt{s_{NN}}=5.02$ TeV requires an additional contribution of two-kaon coalescence, which indicates approximately 20% influence of final-state hadronic rescattering on $v_2$ of $\varphi$ at $\sqrt{s_{NN}}=5.02$ TeV. Using $v_2$ and $v_3$ of light-flavor quarks obtained in studying light-flavor hadrons and $v_2$ and $v_3$ of charm quarks determined from $D^0$ meson data, we apply the EVC model to predict the anisotropic flows of $D_s^{+}, {\mathrm{\Lambda }}_c^{+}, {\mathrm{\Xi }}_c^0$, and ${\mathrm{\Omega }}_c^0$ and compare them with the available experimental data. The preliminary data for $v_2$ of $D^0, D_s^{+}$, and ${\mathrm{\Lambda }}_c^{+}$ at $\sqrt{s_{NN}}=$ 5.36 TeV are found to be naturally described by the EVC model.

We compare the longitudinal deposition of various conserved quantities in the initial condition models of a string based (SMASH) and a saturation based (McDipper) approach. SMASH has been shown to work reasonably well at lower collision energies as an initial condition for the SMASH-vHLLE hybrid approach, while McDipper, based on the color-glass-condensate, works well in the regime of perturbative quantum chromodynamics. The two models are capable of providing longitudinally resolved initial conditions, which is essential for three-dimensional hydrodynamical simulations. The goal of this study is to interface the different regions of applicability of the two models, to investigate the initial state dynamics in the intermediate energy regime. We analyze the deposition of transverse energy, charge and baryon number across a large range of collision energies (62.4 GeV to 5.02 TeV) and find that, while they are good agreement at lower energies, their energy and baryon deposition differs substantially at higher center of mass energies.

We investigate the exclusive semileptonic decays of $\mathrm{\Lambda }\to p{\ell }^{-}{\overline{\nu }}_{\ell }(\ell =e,\mu )$ within the standard model using the light-front quark model. The transition form factor behaviors of $\mathrm{\Lambda }\to p$ are obtained from the effective treatment of nonvalence contributions in addition to the valence ones in the Drell-Yan-West frame due to the Bethe-Salpeter formalism. Based on these form factors, we obtain that the branching ratios of $\mathrm{\Lambda }\to p{e}^{-}{\overline{\nu }}_e$ and $p{\mu }^{-}{\overline{\nu }}_{\mu }$, including nonvalence contributions, are around $8.32\times {10}^{-4}$ and $1.31\times {10}^{-4}$, which are consistent with the latest measurements from the BESIII Collaboration, respectively. Our results indicate that nonvalence contributions can play a non-negligible role in the semileptonic baryon decays within the light-front framework.

The effects of shape evolution, pairing correlation, and isospin asymmetry on the bubble structure and the symmetry energy of nuclei have been studied systematically for the even-even Yb isotopes within the covariant density functional theory. The shape of nuclei turns out to play its role in the central depletion. The prolate shape nuclei exhibit more pronounced bubble characteristics than the nuclei with oblate configuration, while the pairing correlation reduces the depletion. The depletion fraction in the region of the major shell with the $3{\mathrm{s}}_{1/2}$ orbital decreases with an increase in quadrupole deformation, and occupation probabilities of the $3{\mathrm{s}}_{1/2}$ orbital. Beyond the fully occupied $3{\mathrm{s}}_{1/2}$ energy level, the depletion increases with an increase in the isospin asymmetry parameter. The nuclear deformation and the presence of central depletion are found to impact the nuclear charge form factors and phase shifts, and thus provide direct signatures in electron-nucleus scattering. The charge form-factor analysis, including relativistic spin-orbit and Darwin-Foldy corrections, reveals that the observed diffraction patterns in deformed Yb isotopes arise from a nontrivial interplay among central density depletion, nuclear size, and shape-induced modifications of the monopole charge-density distribution. Scaling the momentum transfer with the rms charge radius demonstrates that the form-factor differences cannot be attributed solely to nuclear size, while residual differences indicate a measurable sensitivity to the underlying interior density profile.

An improved treatment of high-momentum components in nuclei is introduced in the framework of the dispersive optical model (DOM). The well-established feature that the peak of the spectral function appears at higher excitation energy in the $A-1$ system with increasing momentum has so far not been successfully accounted for in the DOM. To achieve this feature, it is necessary to abandon the factorization of energy dependence and geometry of the DOM self-energy. The volume absorption below the Fermi energy has thus been represented by a decreasing radius at larger missing energy, implying that a numerical treatment of the dispersion relations is necessitated. Earlier DOM results for ${}^{48}\mathrm{Ca}$ are also improved with this approach, demonstrating that a small neutron skin can still be accompanied by protons having a larger high-momentum tail than neutrons.

Within the continuum random-phase approximation formulated via the Jost function method, I formulate a microscopic method to (i) evaluate nuclear collectivity through a dimensionless metric normalized to unity for a pure single-channel excitation, and (ii) extract partial decay widths and branching ratios directly from complex channel amplitudes without artificial width broadening. By applying rank-1 Takagi factorization to the complex symmetric scattering matrix residue at resonance poles across multiple Riemann sheets, the transition strength residue is algebraically partitioned into the single-particle radial overlap scale, multichannel participation coherence, and operator phase alignment. To validate the effectiveness and physical consistency of this framework, benchmark calculations are performed for ${}^{16}\mathrm{O}$ across diverse continuum excitation modes: (i) for the isovector giant dipole resonance, the metric identifies a strongly multichannel collective response decaying concurrently through multiple open channels; (ii) for the isoscalar quadrupole channel, the metric characterizes the strong collectivity of the low-lying resonance concentrating the low-energy transition strength, while higher core-excited states exhibit suppressed direct excitation and destructive continuum interference; and (iii) for the isovector quadrupole channel, the metric clearly reveals that the most prominent strength peak is a noncollective quasi-single-particle resonance trapped behind a centrifugal barrier, whereas collective isovector giant quadrupole resonance components are pushed up and fragmented across higher-energy Riemann sheets. This work establishes a transparent diagnostic tool for characterizing continuum resonances and decay branching, providing a practical framework for future applications to heavier nuclei where collective phenomena fully develop.

We performed high-precision mass measurements of the proton-rich nuclei ${}^{52}\mathrm{Ni}$ and ${}^{51}\mathrm{Co}$ with the LEBIT Penning trap at the Facility for Rare Isotope Beams. For ${}^{52}\mathrm{Ni}$, a mass excess of $-22474.8\left(2.2\right)$ keV was determined, which is consistent with a recent storage-ring measurement at the Cooler-Storage Ring (CSRe) but has a factor 37 improved precision. For ${}^{51}\mathrm{Co}$, we obtained a mass excess of $-27375.1\left(5.7\right)$ keV, agreeing with a recent CSRe result, while reducing the uncertainty by a factor 2. Combining our mass value for ${}^{52}\mathrm{Ni}$ with the known two-proton decay energy of ${}^{54}\mathrm{Zn}$, we determined the mass excess of ${}^{54}\mathrm{Zn}$ to be $-6463\left(42\right)$ keV. These new mass values reveal a substantial breakdown of the isobaric mass multiplet equation for $A=52$ and $A=54$, and provide stringent benchmarks for isospin-symmetry-breaking effects in the proton-rich $fp$-shell, favoring theoretical descriptions that omit the Coulomb-exchange term.

The structure of high-$K$ isomeric states in the odd-$A$ tantalum $(Z=73)$ isotopes is investigated systematically within the cranked Nilsson–Strutinsky (CNS) and cranked Nilsson–Strutinsky–Bogoliubov (CNSB) frameworks, spanning neutron numbers $N=106–116$. The low-lying one-proton isomers are identified with the $9/2^{-}\left[514\right]$, $5/2^{+}\left[402\right]$, and $1/2^{+}\left[411\right]$ Nilsson orbitals, while the two-quasineutron configurations $K^{\pi }=8^{-}$, ${10}^{+}$, and ${10}^{-}$ are shown to play a decisive role in driving multiquasiparticle isomer formation across the chain. High-$K$ isomers are predicted in ${}^{189}\mathrm{Ta}$ at low excitation energies, presenting a strong motivation for future experiments. The CNSB calculations predict a transition from stable prolate shapes to triaxiality and shape coexistence in odd-$A$ Ta isotopes near $N=114–116$.

The neutron-skin thickness in neutron-rich nuclei has traditionally been measured using low-energy hadronic and electronic scatterings at hadronic level. In this paper, we propose an alternative probe to the neutron-skin thickness through deep-inelastic scattering in high-energy electron-ion collisions, leveraging the intrinsic correlation between final-state jet charge distribution and initial-state partonic distributions in nucleons. Specifically, we demonstrate the sensitivity of jet charge distribution to the neutron skin-thickness and density profile in $e+\mathrm{Pb}$ collisions with varying centralities as determined using Glauber model, and in isobar collisions of $e+\mathrm{Ru}$ and $e+\mathrm{Zr}$. We predict a strong suppression of positive jet charge distribution and an enhancement for negative jet charge distribution in peripheral electron-ion collisions, revealing the neutron-skin effect. Premised on the effective determination of centrality, this proposal can also be extended to photon and Z-boson tagged jet charge distribution in proton-nucleus collisions at the Large Hadron Collider, providing another similar access to neutron-skin structure.