In nuclear fission, the primary fragments deexcite through the emission of neutrons and $\gamma$ rays. This prompt emission conveys information about the initial angular momentum and excitation energy of the fragments at scission and is therefore important for improved understanding and modeling of the fission process. A long-standing question is how much the angular momentum $J$ of a fragment is changed after scission due to the evaporation of neutrons. Though few experimental data are available, the consensus has been that the neutrons carry only a small amount of $J$ on average (around $0.5\hslash$ per neutron), while the majority (typically $6\hslash –7\hslash$) is removed via $\gamma$-ray emission. This consensus was recently challenged [I. Stetcu et al., Phys. Rev. Lett. 127, 222502 (2021)], instead suggesting values $>1.2\hslash$ per neutron. Since the question of how much neutron emission impacts $J$ is important for understanding fission fragment deexcitation, we seek here to put experimental constraints on this value. An experiment was carried out with the nu-Ball2 Ge detector array to perform $\gamma$-ray spectroscopy of fission fragments produced in the ${}^{238}\mathrm{U}(n,\mathrm{f})$ reaction. A spectroscopic method [Y. Abdelrahman et al., Phys. Lett. B 199, 504 (1987)] was employed to determine average angular momenta after neutron emission for even-even fission fragments. By simultaneously selecting $\gamma$ rays from both a particular fission fragment and its partner fragment, the total number of neutrons emitted could be deduced in each event. The average fragment $J_{\text{e}}$ is extracted from measurements of the yrast feeding pattern of the selected fragment. Here we investigate the dependence of this observable on the number of neutrons emitted by studying 53 different fragment pairs. The uncertainty weighted dependences of the average change in entry-line spin with the total number of neutrons emitted are $(-0.03\pm 0.03)\hslash$ and $(-0.21\pm 0.04)\hslash$ for the light and heavy fragments, respectively. These results are interpreted in combination with other recent works in the literature.

Nucleosynthesis reaction networks leading to $p$ nuclei involve a combination of different types of photodisintegration and capture reactions, as well as ${\beta }^{+}$ decays or electron captures. Photodisintegration reactions involving $\alpha$ particles present a particular interest as they serve as branching points of the reaction networks. The cross sections of these reactions depend crucially on the $\alpha$-nucleus interaction. The $\alpha$-optical model potential (AOMP) is determined mostly by means of experimental differential elastic scattering distributions. Several previous studies have focused on the case of ${}^{144}\mathrm{Sm}$, an intriguing $p$ nucleus that is semimagic with 82 neutrons. This work presents new experimental data on $\alpha$ elastic and inelastic scattering on ${}^{148}\mathrm{Sm}$, its closest stable isotope. Isotopic effects on the description of the AOMP are studied, as well as their consequences on the prediction of $\alpha$-induced reaction cross sections at astrophysical energies. It is shown that the isotopic ratio for $(\alpha ,\gamma )$ cross sections can be multiplied up to a factor of two when these effects are included.

Background: The excitation of the one-neutron halo nucleus ${}^{15}\mathrm{C}$ from the $1/2^{+}$ ground state to the $5/2^{+}$ first excited state was measured at Argonne National Laboratory by impinging ${}^{15}\mathrm{C}$ on a deuterated target at $7.1A$ MeV. These data were then analyzed in the distorted-wave Born approximation (DWBA) using a rigid rotor model for the excitation.

Purpose: Being a one-neutron halo, we expect a single-particle excitation to better represent the excitation of ${}^{15}\mathrm{C}$ rather than a collective process. We expect the breakup of ${}^{15}\mathrm{C}$ to influence the reaction mechanisms because of the low one-neutron separation threshold, which is close in energy to ${}^{15}\mathrm{C}$'s first excited state. The goal of this work is to explore the various reaction mechanisms to reinterpret the data of J. Chen et al. [Phys. Rev. C 106, 064312 (2022)] for the inelastic excitation of ${}^{15}\mathrm{C}$.

Method: We solve the scattering problem assuming the three-body model ${}^{14}\mathrm{C}+n+d$. We use the continuum-discretized coupled-channels method (CDCC) and compare the results with those obtained assuming one-step DWBA with quadrupole deformation, as done in the original experimental analysis. We also use Bayesian uncertainty quantification to estimate the uncertainties in our predictions coming from the $n\text{−}d$ interaction.

Results: We analyze both the elastic and inelastic angular distributions for ${}^{15}\mathrm{C}(d,d^{\prime }){}^{15}\mathrm{C}^{*}$ at $7.1A$ MeV. Our results show that ${}^{15}\mathrm{C}$ breakup effects are important.

Conclusions: While CDCC predicts the elastic angular distribution correctly, it is not able to fully describe the experimental inelastic angular distribution. We discuss additional effects that may be responsible for the remaining discrepancy.

Radial-flow fluctuations are discussed using the $p_{\mathrm{T}}$-differential measure $v_0\left(p_{\mathrm{T}}\right)$, together with its $p_{\mathrm{T}}$-integrated counterpart $v_0$, within the framework of geometrical scaling (GS), where the saturation momentum scale provides the characteristic scale for particle production. It is shown that the GS framework leads to results similar to those obtained from the momentum-rescaling model proposed by [J. Jia, Phys. Rev. Lett. 136, 112301 (2026)]. In the GS picture, event-by-event spectral fluctuations are governed by fluctuations of the saturation momentum scale; consequently, the single-mode ansatz introduced in Jia's model emerges naturally. The GS picture also suggests a possible connection between transverse-momentum correlations and fluctuations of the emission region, which may be probed through Hanbury-Brown and Twiss analyses. Using the string percolation model, which is closely related to GS, the multiplicity dependence of radial-flow fluctuations is estimated, and the scaled quantity $A_0\left(N_{\mathrm{\Delta }y}\right)\equiv v_0^2{N}_{\mathrm{\Delta }y}$, with $N_{\mathrm{\Delta }y}=(dN/dy)\mathrm{\Delta }y$, is proposed as a diagnostic observable for testing the role of effective flux-tube fluctuations.

In this work, we present the first extension of the many-body forces (MBF) model to finite temperature. The MBF model describes nuclear matter in a relativistic quantum hadrodynamics formalism that takes many-body forces into account through a field dependence of the nuclear interaction coupling constants. Assuming nuclear matter to be charge neutral, $\beta$-equilibrated, and populated by the baryon octet, electrons, muons, and neutrinos, we explore the parameter of the model that controls many-body forces, three different hyperon coupling schemes (also introduced here for the first time in the MBF model), and temperature effects to describe basic properties of nuclear matter, including the speed of sound, compressibility, and adiabatic index. We also investigate the mass-radius relation of neutron and proto–neutron stars by solving the Tolman-Oppenheimer-Volkoff equations at zero and finite temperature, including scenarios with fixed entropy per baryon and lepton fraction. We find that different hyperon coupling schemes soften the equation of state to different degrees, requiring different degrees of many-body force effects to reproduce observations, although they are never zero. Multidimensional tables with our results are available in the CompOSE repository, ready to be used in astrophysical simulations.

This paper presents a high-precision Nyström quadrature-discretization method for the coordinate-space Lippmann-Schwinger equation. While the direct application of the Nyström approach is hampered by the derivative jump in the free Green's function, a robust subtraction and smoothing procedure is introduced to regularize this discontinuity. Tested on $p$- and $d$-wave scattering for two model potentials, this regularization is shown to be essential for numerical stability, yielding 8-digit accuracy for the partial-wave $S$ matrices with a relatively small set of quadrature points. Because full Nyström matrices can become computationally prohibitive for large-scale applications, there exists a need for contracting this high-fidelity information into a more compact representation. Petrov-Galerkin approaches appear appropriate for this purpose. Among many possibilities, the Bateman approximation, Schwinger variational method and Newton variational method appear especially promising. Bateman method for the resolvent is of interest because an interesting connection exists between Nyström and Bateman methods. Numerical results confirm that the Bateman procedure successfully reduces the information content of large-scale Nyström calculations into a compact form with reasonable accuracy, while the Schwinger and Newton variational methods exhibit even higher efficiency in this reduction task. This compression of high-fidelity Nyström information into a minimal basis resembles the data-contraction techniques prevalent in modern machine learning and emulation.

While chiral perturbation theory for mesons is characterized by a momentum expansion in $Q/{\mathrm{\Lambda }}_{\chi }$ with ${\mathrm{\Lambda }}_{\chi }\approx 1\mathrm{GeV}$, existing formulations of effective theory for nucleon-nucleon scattering deviate from data at $Q\approx 300\mathrm{MeV}$ or lower. We offer heuristic evidence that unsuspected nonanalytic structure exists in the complex momentum plane obstructing the effective field theory expansion in the spin-triplet channels, associated with the peak of the angular-momentum barrier whose energy in low partial waves satisfies $k=\sqrt{ME}\approx 300\mathrm{MeV}$. With this motivation, we construct a meromorphic function of $k^2$ we call the $C$-matrix, for which the radius of convergence of its Taylor expansion in $k^2$ is equivalent to that of the momentum expansion of the effective field theory. Thus the range of validity of the effective theory is directly related to the pole structure of the $C$-matrix. We uncover that pole structure and confirm that it is the source of the obstruction. The systematic inclusion of dimer fields as propagating degrees of freedom in the effective theory to account for those poles results in cutoff insensitive fits at order $Q^0$ to most of the lower partial-wave phase shifts up to the pion production threshold, using only the one pion exchange part of the long-range nucleon-nucleon interaction. Our theory should be applicable to the singular potentials regularly found in atomic physics as well.

The possible antimagnetic rotation in the $N=46$ odd-$A$ isotones ${}^{83}\mathrm{Rb}$ and ${}^{85}\mathrm{Y}$ is investigated using the cranked shell model combined with a particle-number-conserving method. For the positive-parity yrast bands in the two isotones, the angular-momentum alignments are reproduced well. The configurations of high-spin part in both bands are determined as $\pi g_{9/2}\otimes \nu g_{9/2}^{-4}$, by analyzing the occupation probability of each cranked Nilsson orbital near the Fermi surface. The calculated $B\left(E2\right)$ values are small and decrease with the increasing rotational frequency, in agreement with the experiments; meanwhile, the two-shears-like mechanism is exhibited clearly. Therefore, the high-spin parts of the two bands, built on $\pi g_{9/2}\otimes \nu g_{9/2}^{-4}$ configuration, match the criteria of antimagnetic rotation, which is the first time that the antimagnetic rotation is revealed for odd-$A$ nuclei in the $A\approx 80$ mass region.

A configuration-interaction time-dependent density functional theory (CI-TDDFT) for nuclear dynamics is developed. In this framework, the correlated nuclear many-body wave function is expanded in terms of time-dependent many-particle configurations built from a common set of orthonormal single-particle states. The equations of motion for both the expansion coefficients and the single-particle states are derived self-consistently using the Dirac-Frenkel time-dependent variational principle. This formulation extends conventional time-dependent density functional theory (TDDFT) by incorporating configuration mixing and beyond-mean-field correlations, while preserving energy and particle-number conservation. As an illustrative application, the method is implemented using the relativistic point-coupling functional PC-PK1 in the particle-hole channel and a monopole pairing interaction in the particle-particle channel and is applied to the study of isoscalar giant monopole resonance in ${}^{58}\mathrm{Ni}$ and ${}^{60}\mathrm{Ni}$. Numerical tests show that both the total energy and particle number are conserved, with relative deviations within $4\times {10}^{-4}$ during the time evolution. Compared with conventional TDDFT, CI-TDDFT yields broader strength distributions for giant monopole resonances while keeping the main peak positions close to those from TDDFT. This broadening is associated with configuration mixing in the valence space and suggests a coupling of the monopole oscillation to additional collective degrees of freedom. These results demonstrate the potential of CI-TDDFT as a quantum, microscopic beyond-mean-field framework for nuclear dynamics.

Within the framework of Lanzhou quantum molecular dynamics transport model, the cluster dynamics and double differential cross sections in the spallation reactions have been systematically investigated. The cluster yields are contributed from the preequilibrium emission in the cascade collisions and from the statistical decay via the hot fragments, in which the surface coalescence and GEMINI statistical decay are used for the cluster production. The spallation reactions of proton, deuteron, triton, ${}^3\mathrm{He}$, and $\alpha$ on ${}^{208}\mathrm{Pb}, {}^{209}\mathrm{Bi}$, and ${}^{232}\mathrm{Th}$ are systematically investigated. It is demonstrated that the energetic clusters are mainly contributed from the preequilibrium emission, in particular, at the kinetic energies above 30 MeV. The more bound nucleus is available for the production in the spallation reactions, i.e., the larger yields for $\alpha$ in comparison with ${}^3\mathrm{He}$. The kinetic energy tail of cluster production is enhanced with increasing beam energy. The low-energy clusters are mainly produced from the decay of hot fragments and correlated with the energy deposition of incident nuclides. The experimental double differential cross sections are well reproduced within the combined approach.

We perform a theoretical study of intermediate-energy quasifree one-proton knockout reactions on proton targets. Single-particle wave functions constrained by the experimental proton separation energies are employed to calculate longitudinal momentum distributions, one-proton removal cross sections, and full momentum-space profiles for ${}^{26}\mathrm{P}, {}^{27}\mathrm{S}$, and ${}^{31}\mathrm{Ar}$ nuclei. To establish robust criteria to identify proton halos, the analysis is extended beyond the traditional momentum-width approach by investigating the spatial extension of the valence proton through root-mean-square radii and the probability that the proton resides outside the core nucleus, $P(r>R_{\mathrm{core}})$. We also examine Coulomb-barrier systematics, mirror-nucleus comparisons, realistic spectroscopic mixtures, finite experimental momentum resolution, and uncertainties associated with the proton separation energy. Our calculations indicate that proton-halo structure cannot be identified reliably from a single observable. A consistent interpretation emerges only when momentum distributions, spatial observables, Coulomb effects, and many-body structure are considered simultaneously. Within the present model, ${}^{26}\mathrm{P}$ exhibits the strongest proton-halo signatures, while ${}^{27}\mathrm{S}$ retains pronounced halolike features despite its larger Coulomb barrier. The more strongly confined ${}^{31}\mathrm{Ar}$ provides a useful comparison and illustrates the progressive suppression of halo observables with increasing binding and core charge.

This study validates and generalizes the intermediate-energy α-induced reaction model originally developed in [Phys. Rev. C 112, 024616 (2025)]. We measured double-differential cross sections for five emission channels ($p, d, t, {}^3\mathrm{He}$ and α) using C and Co targets at 230 MeV/u. By optimizing the transition impact parameter $b_{\mathrm{tr}}$ for each target, it was found to be expressed as $1.2R-3a$, where $R$ is the nuclear radius and $a$ is the diffuseness parameter, reflecting the nuclear-size dependence. The model, employing this universal formulation, successfully reproduced the new experimental data. Furthermore, using the parameters determined from the 230 MeV/u data, the model was tested against existing data at different incident energies up to 800 MeV/u; remarkably, it demonstrated high predictive accuracy without any additional parameter adjustments.

The excited states of ${}^{209}\mathrm{Po}$ have been investigated via the ${}^{208}\mathrm{Pb}(\alpha ,3n){}^{209}\mathrm{Po}$ reaction, at a beam energy of 40 MeV delivered by the K-130 cyclotron at the Variable Energy Cyclotron Centre, Kolkata. The deexcited $\gamma$ rays were detected with the Compton-suppressed clover high-purity germanium detectors of the Indian National Gamma Array setup. The level scheme has been significantly extended by identification and placement of 63 new $\gamma$-ray transitions. The spin-parity assignments of the different levels have been carried out on the basis of directional correlation of oriented states and polarization asymmetry measurements. Additionally, the possible presence of an isomeric state at a spin of $23/2^{+}$ has been indicated. Large-scale shell model calculations have been performed, with the inclusion of excitations of neutrons across the $N=126$ core, and compared with the experimental results.

One-proton emission is a direct probe of nuclear structure near the proton drip line and plays a critical role in understanding exotic decay modes and nucleosynthesis processes. In this study, we investigate the half-lives of one-proton emitters for $71\le Z\le 83$ odd-$Z$ nuclei by employing the WKB approximation with nuclear potentials obtained from the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) and, for comparison, the relativistic continuum Hartree-Bogoliubov theory. We first compare the calculated half-lives with available experimental data. The inclusion of quadrupole deformation via the DRHBc hardly contributes to improving the predictions of half-lives for the deformed nuclei. We find that all the studied nuclei exhibit ground states with $|{\beta }_{2,\mathrm{DRHBc}}|<0.15$, and within this limited deformation range the spectroscopic factor provides the dominant contribution to the half-life, compared to the decay width. In particular, for nuclei exhibiting shape coexistence in DRHBc, such as ${}^{170}\mathrm{Au}$, where the half-life varies significantly with the quadrupole deformation through its effect on the spectroscopic factor, we expect shape coexistence to exert a substantial influence on the variation of half-lives. Finally, we discuss the half-lives in consideration of shape coexistence. Our results indicate that the calculated half-life is governed not by the total-energy difference between coexisting minima but rather by the spectroscopic factor influenced by the deformation.

Studies of the isoscalar giant monopole resonance (ISGMR) across the chart of nuclides provide insight into the incompressibility of nuclear matter near saturation density, $K_{\infty }$. Such studies had revealed a discrepancy between theoretical approaches: quasiparticle random-phase approximation (QRPA) derived from Skyrme interactions reproduce the strength distributions of the ISGMR in the “doubly-closed-shell” nuclei ${}^{90}\mathrm{Zr}$ and ${}^{208}\mathrm{Pb}$, but their descriptions of strength distributions in open-shell medium-heavy nuclei suggest higher centroid energies should be experimentally observed. The latter nuclei required a smaller $K_{\infty }$ and were thus deemed “softer.” The present work serves to add to this “softness” discourse by extracting ISGMR strength distributions for ${}^{104,106,108,110}\mathrm{Pd}$ via 386-MeV inelastic $\alpha$ scattering. The extracted giant resonance strength distributions are consistent with expectations in this isotopic range. Additional quasiparticle vibration coupling (QPVC) effects are included with the QRPA approach and compared to aforementioned ISGMR strength distributions.

Islands of inversion occur when the nuclear ground state is dominated by intruder configurations, specifically particle-hole excitations across shell gaps, rather than by the naive spherical shell-model expectation of filled shell configurations. Using the realistic and rigorous no-core shell model, we are able to confirm that deformation drives these intruder states in the light halo nuclides ${}^{11}\mathrm{Li}$ and ${}^{29}\mathrm{F}$. In small model spaces, these deformed intruders lie high in energy with respect to spherical normal states; as the model space size increases, the intruders energetically approach, albeit slowly, the normal states. This provides further strong evidence of the connection between shape deformation or coexistence and islands of inversion, as well as demonstrating the computational challenges in rigorously modeling this phenomenon. Our results also suggest halo states can be strongly deformed and/or strongly mixed with normal spherical states.

We have employed Bayesian inference to extract the centroid energies and widths from the isovector giant dipole resonance (IVGDR) data for the IVGDR built on the ground states of nuclei. These IVGDR properties were modeled by explicitly incorporating the structural effects like isospin asymmetry, nuclear deformation, and shell correction. The resulting parametrizations reproduce the IVGDR systematics with remarkable precision for both spherical and axially deformed nuclei. Subsequently, the extracted IVGDR parameters were used to constrain the coefficients of the nuclear symmetry energy, which are found to be in good agreement with recent measurements of nuclear dipole polarizability. Furthermore, these symmetry-energy coefficients were employed to predict the dipole polarizability within different self-consistent mean-field models and to investigate its correlation with the neutron-skin thickness. The present findings provide valuable input for large-scale calculations of radiative capture processes relevant to nuclear astrophysics and for improving our understanding of astrophysical scenarios under extreme conditions.

Photoneutron double-differential cross sections in the giant dipole resonance (GDR) region were calculated to investigate the underlying nuclear reaction mechanisms with particular emphasis on the role of the direct process. Contributions from direct, pre-equilibrium, and compound processes were all taken into account. Wilkinson's resonance direct (RD) theory, based on the independent particle model, was applied to describe high-energy neutron emission from the direct process. The angular distribution of neutrons emitted via the RD mechanism was formulated using the Agodi and Courant formalism, which was incorporated into the RD framework. Neutron emission from the pre-equilibrium and compound processes was calculated using the two-component exciton model and the Hauser–Feshbach formalism, respectively. The calculated results were compared with experimental data obtained at NewSUBARU using 16.6-MeV quasi-monochromatic linearly polarized photon beams. Good agreement between calculations and measurements was observed for Pb, Au, and Sn, confirming the validity of the proposed model. Furthermore, the angular anisotropies of photoneutrons emitted from these elements were investigated, revealing considerable contributions from the RD process at high neutron energies. This study provides a deeper understanding of photoneutron emission mechanisms in the GDR energy region.

The observed fluid behavior of the matter produced in heavy ion and $pp$ collisions implies that the strings stretched between the constituents of the projectile and target should have a hard core giving rise to a repulsion between them. It is shown that in these collisions there are two critical string densities, one corresponding to the well-studied percolation of strings and another to the percolation of the hard core of the strings. These two critical densities are related to two critical temperatures, one $T\approx 160$ MeV would correspond to the restoration of chiral symmetry and partial deconfinement and a second transition $T\approx 220$ MeV form the fluid behavior of quantum chromodynamics matter strongly interacting to a quasi free gas of quarks and gluons. This argument is supported by the recently published results on the sudden increase in the degrees of freedom above the deconfinement temperature in $pp$ and $A\text{−}A$ collisions [Mishra et al., Nucl. Phys. A 1046, 122865 (2024)].

We developed a theoretical approach to elastic electron scattering on nuclei that includes a two-photon-exchange mechanism responsible for parity-conserving single-spin beam asymmetries. The two-photon-exchange amplitude at small scattering angles is treated in a diffractive framework similar to that used for pion-nucleus elastic scattering, and the approach is applied to the nuclei ${}_6^{12}\mathrm{C},{}_{20}^{40}\mathrm{Ca}$, and ${}_{82}^{208}\mathrm{Pb}$. The predicted kinematic features of the beam polarization asymmetries for different nuclei may reconcile Jefferson Lab's experimental results at finite scattering angles with a forward limit given by an optical theorem, potentially resolving the so-called “PREX puzzle” for ${}_{82}{}^{208}\mathrm{Pb}$.