Papers

Background: The deformed halo nucleus $^{31}$Ne exhibits unique structural properties arising from the interplay between its halo neutron and the deformation of the $^{30}$Ne core. While previous studies have established the nature of its weakly-bound ground state through reaction cross sections and inclusive breakup measurements, the structure of its excited states in the low-energy continuum, which are expected to appear as resonances, remains largely unexplored. Purpose: We investigate the structure of these resonant states and clarify their rotational nature and formation mechanism. Method: The structure of $^{31}$Ne is described using the particle rotor model (PRM), which explicitly treats the coupling between core excitation and single-particle motion in both bound and continuum states. Results: The calculations predict the emergence of unbound rotational states in the low-energy continuum of $^{31}$Ne, which form a rotational sequence built on the weakly-bound Nilsson [321 3/2] configuration. As the total angular momentum increases along the rotational band, the intrinsic Nilsson structure is largely preserved, whereas the dominant core-spin component shifts to higher spins. These resonances are stabilized through the combined effects of coupling to higher-lying closed core-excited channels and reduced effective neutron relative energies, and can therefore be interpreted as rotational Feshbach resonances. Conclusion: The present study elucidates the formation mechanism of rotational Feshbach resonances in $^{31}$Ne. This mechanism is expected to be a general feature of weakly-bound deformed nuclei. Exclusive breakup measurements with coincident detection of $\gamma$ rays from the de-exciting core will provide crucial tests of the proposed formation mechanism of rotational Feshbach resonances.

Running an unfamiliar nuclear-physics code is rarely difficult because of the physics alone. One must find and build the program, learn its input conventions, and decide whether a plausible output is actually correct. A general-purpose coding agent helps with the first two tasks but may make the last one harder: it can write an input file that runs with the wrong physical convention. FUSION addresses this problem with code-specific skills. A skill obtains the code from its public source, starts from a verified input, runs and parses the calculation, records known failure modes, and must reproduce a stated benchmark to a stated tolerance before reporting a result. The current release covers twenty codes, spanning optical models and reactions, nuclear structure, fission and statistical models, astrophysics and R-matrix analysis, and heavy-ion transport. It also includes an offline, searchable collection of 61 167 pages derived from the nucl-th literature. User notes and credentials remain outside the public repository. FUSION is available under the MIT license at https://github.com/jinleiphys/FUSION; documentation is at https://vibeinscience.com. Here I describe the design, the checks behind the current release, and one complete calculation from input to comparison with measured data.

In this work, we systematically investigate the baryon-baryon interactions in singly bottomed dibaryon systems within the chiral quark model and search for possible bound states. By exploring the baryon-baryon interaction, we find that low-isospin channels tend to generate deeper attractive interactions and are prone to form bound states. We also find that decuplet-decuplet systems tend to show stronger attraction and support a larger number of bound states, whereas octet-octet systems generally exhibit weaker attraction and fewer bound solutions. The binding behavior of octet-decuplet systems generall lies between these two cases. Several bound states are obtained, which are $\Delta\Sigma_b^*$ with $IJ=\frac{1}{2}0$, $\frac{1}{2}1$, $\frac{1}{2}2$, $\frac{1}{2}3$, and $\frac{3}{2}3$, the $\Delta\Sigma_b$ with $IJ=\frac{1}{2}1$, $\frac{1}{2}2$, $\frac{3}{2}1$, and $\frac{3}{2}2$, the $N\Sigma_b^*$ with $IJ=\frac{1}{2}2$, the $\Sigma\Sigma_b$ with $IJ=00$, $01$, and $11$, the $\Sigma\Sigma_b^*$ with $IJ=01$ and $02$, the $\Sigma^*\Sigma_b$ with $IJ=01$ and $02$, and the $\Sigma^*\Sigma_b^*$ with $IJ=00$, $01$, $02$, $03$, and $13$. Further investigations of the corresponding scattering processes are still required to determine whether these bound-state candidates can be identified. These states deserve further experimental investigation.

Working through next-to-next-to-leading order (NNLO) accuracy in pionless effective field theory, we compute the isovector magnetic-dipole contribution to the scalar deuteron magnetic polarizability. The polarizability follows from detailed balance and a dispersion integral with the two magnetic current counter-terms fixed by the thermal $np\to d\gamma$ rate. The conventional $\rho$ and $Z$ expansion schemes differ by $12.3\%$ at next-to-leading order but agree to $0.165\%$ at NNLO, resulting an apparent scheme dependence and supplying an independent convergence diagnostic. We obtain $\beta_{M0}^{(M1_v)}=0.0789\pm0.0010~\mathrm{fm}^{3}$, a $1.3\%$ uncertainty, compared with $4.9\%$ previously.

Recently, a new Trojan Horse Method (THM) measurement of carbon-carbon fusion was reported by Li et al. [Phys. Lett. B (2026) 140675]. The purpose of the present work is to demonstrate the breakdown of the plane-wave approximation used in the analysis of these data and the critical role of Coulomb distortions in the initial and final states. The reaction mechanism underlying the THM analysis of the $^{12}\mathrm{C}+{}^{12}\mathrm{C}$ fusion reaction using the $^{16}\mathrm{O}+{}^{12}\mathrm{C}\to \alpha_s+\alpha+{}^{20}\mathrm{Ne}$ reaction is investigated. Particular attention is paid to the spectator momentum distribution and to the dependence of the THM reaction amplitude on the relative carbon-carbon energy $E$. It is demonstrated that agreement with the measured spectator momentum distribution does not by itself validate the plane-wave approximation. Although the experimental momentum distribution can be reproduced, inclusion of Coulomb distortions in both the initial and final channels leads to an energy dependence of the THM amplitude that is completely different from the plane-wave result. Consequently, the energy dependence of the $^{12}\mathrm{C}+{}^{12}\mathrm{C}$ fusion cross section extracted from the THM data can be strongly distorted by the plane-wave treatment. It is concluded that the astrophysical factor extracted in the plane-wave analysis cannot be regarded as reliable and may lead to misleading conclusions concerning the low-energy $^{12}\mathrm{C}+{}^{12}\mathrm{C}$ fusion reaction.

The astrophysical $S$-factor plays an important role in extrapolating the laboratory cross section data to lower energies of relevance in nucleosynthesis calculations. Be it empirical fits or theoretical modeling of the $S$-factors, experimental information on the cross sections over a range of energies is essential to provide reliable $S$-factors and thereby the nuclear reaction rates which enter the nucleosynthesis networks. In view of the scattered and sometimes diverse data on the same reaction in literature and the databases, we present a compilation and review of available data from 318 references involving 371 experiments on the leading and sub-leading reactions in big bang nucleosynthesis (BBN). Salient features such as bumps at certain energies and a steep rise in the $S$-factor at low energies due to screening effects are found to vary in different experiments. The latter depends on the variation of targets and sometimes temperature to extract information on the same nuclear reaction. For instance, 45 cases in which the $S$-factor at low-energy could present electron screening-effect showed deviations from background values with features which are unique to each experiment, target and temperature. The extensive compilation, discussions of the relevance of each reaction in BBN and the features of the $S$-factors is followed by a presentation of empirical fits to the $S$-factors in some selected reactions of interest. This is a preprint of the following work: Carlos A. Salas and Neelima G. Kelkar, Astrophysical S-Factors in Primordial Nucleosynthesis, 2026, SpringerBriefs in Physics. It is the version of the author's manuscript prior to acceptance for publication and has not undergone editorial and/or peer review on behalf of the Publisher (where applicable). The final authenticated version is available online at: https://doi.org/10.1007/978-3-032-30466-7

We study the structure of leading hadronization effects and the contributions of massive electroweak gauge boson exchange in the $\tau_1$ and $\tau_{1a}$ 1-Jettiness global event shapes for deep inelastic scattering (DIS). The leading hadronization effects in $\tau_1$ acquire a non-trivial dependence on the hard scattering kinematics. This kinematic dependence is explicitly calculable, so that the leading hadronization effects in $\tau_1$, $\tau_{1a}$, and DIS thrust are universal and described by the same underlying shape function. The additional calculable kinematic dependence in $\tau_1$ provides an independent lever arm for simultaneously constraining hadronization effects in these observables. We present corresponding results at the N$^3$LL+${\cal O}(\alpha_s^2)$ level of accuracy. We extend previous results by including the contributions mediated by the exchange of the massive $Z$ and $W$ electroweak gauge bosons for neutral current (NC) and charged current (CC) DIS, respectively, including ${\cal O}(\alpha_s)$ QCD corrections to obtain N$^2$LL+${\cal O}(\alpha_s)$ results. We compare theoretical predictions to Pythia simulation and demonstrate the universality of leading hadronization effects across NC and CC DIS processes and a wide range of kinematics relevant to HERA and the EIC.

Electric quadrupole transition probabilities $B(E2)$ serve as key probe of nuclear shell evolution, yet anomalous $B(E2)$ values in exotic nuclei complicate the identification of new magic numbers. In this letter, employing the configuration-interaction relativistic Hartree-Fock model, we demonstrate that effective charges are sensitive to orbital radii, and this orbital dependence is significantly amplified by the halo structure of valence nucleons. This mechanism is critical for reliably describing $E2$ transitions and understanding the unusual behavior of $B(E2)$ in exotic nuclei. Our calculations predict reduced $B(E2; 2^+_1 \rightarrow 0^+_1)$ values in $^{52,54}\text{Ca}$, signaling the emergence of subshell closures at $N=32$ and 34. Furthermore, the suppressed $B(E2; 7/2^{-}_{1} \rightarrow 11/2^{-}_{1})$ transition in $^{53}\text{Sc}$ underscores the robustness of the $N=32$ new magic number, whereas the enhanced transition strength in $^{55}\text{Sc}$ indicates the rapid erosion of the $N=34$ shell gap with the occupancy of the proton orbital $\pi1f_{7/2}$.

We present the first QCD determination of an energy-dependent form factor for a two-hadron scattering state. In particular, we calculate the QCD contribution to the forward electromagnetic $\pi^+\pi^+ + \gamma\to\pi^+\pi^+$ amplitude at $m_\pi\approx 400$~MeV using lattice QCD. Because lattice calculations are performed in a finite Euclidean spacetime, where asymptotic scattering states are absent, this amplitude cannot be accessed directly from correlation functions. Instead, we can constrain this and related amplitudes nonperturbatively using a finite-volume formalism that requires two ingredients: the discrete finite-volume spectrum and finite-volume matrix elements of the electromagnetic current. We calculate three-point correlation functions coupling $\pi^+\pi^+$ finite-volume states and extract the corresponding electromagnetic matrix elements. Combining these results with the previously determined spectrum, we constrain the infinite-volume $\pi^+\pi^+ + \gamma\to\pi^+\pi^+$ amplitude in the forward limit. Using constraints from Lorentz symmetry, unitarity, and analyticity, we describe this amplitude in terms of a single real-valued energy-dependent two-hadron form factor. The resulting amplitude and form factor agree with the Ward-Takahashi identity across all energies and moving frames considered, providing the first QCD validation of this finite-volume approach and a pathway toward first-principles studies of the electromagnetic structure and electroweak responses of resonances and multi-hadron bound states.

We investigate the fragmentation dynamics underlying the production of fully heavy tetraquarks by means of the TQ4Q2.0 collinear FF set, covering scalar ($0^{++}$), axial-vector ($1^{+-}$), and tensor ($2^{++}$) configurations. The fragmentation inputs are determined within NRQCD factorization for the complete set of relevant partonic channels and are subsequently evolved across heavy-flavor thresholds through the HF-NRevo scheme. Perturbative uncertainties associated with fragmentation-scale variations are consistently propagated together with nonperturbative effects encoded in color-composite long-distance matrix elements. Attention is devoted to the axial-vector sector, whose fragmentation pattern makes it especially sensitive to intrinsic-charm contributions at LHC and FCC energies. TQ4Q2.0 therefore provides an uncertainty-aware framework for exploring fully heavy tetraquark production over a broad kinematic range and for connecting exotic-hadron spectroscopy with the partonic structure of the proton.

Electric quadrupole ($E2$) effective charges are evaluated based on the self-consistent relativistic Hartree-Fock single-particle states, with core-polarization corrections resummed to all orders using the Tamm-Dancoff approximation (TDA). Configuration-interaction relativistic Hartree-Fock (CI-RHF) calculations employing the TDA effective charges well reproduce the $B(E2)$ strength for neon isotopes from stability to the neutron drip line. We find that polarization charges associated with continuum states are significantly quenched due to their extended density distributions and weak coupling to the core, underscoring the critical role of continuum effects in $E2$ transition evaluations for exotic nuclei. Moreover, the CI-RHF model predicts a suppressed $B(E2; 2^+_2 \to 0^+_2)$ in $^{30}$Ne, together with strong in-band $B(E2)$ strengths of the yrast band, suggesting the coexistence of a nearly spherical excited $0^+_2$ state and a deformed ground state within the $N=20$ "island of inversion".

The properties of compact stars with a strong first-order phase transition to quark matter and with an additional fluid of self-interacting bosonic dark matter (DM) are studied. We find that the inclusion of DM changes considerably the stability of mass-radius configurations relative to the naive one-fluid criterion. For compact star configurations with similar masses and different radii, so-called twin stars, the presence of DM removes the unstable segment between the hadronic and the hybrid branch, so that the stable mass-radius sequence becomes continuous after the onset of the phase transition to quark matter. We furthermore find stable ultra-compact objects (UCOs), defined by a total compactness $C = M_\text{tot}/R_\text{grav} \ge 1/3$. We observe two distinct classes of UCOs: a DM-halo class with $f_\text{DM} \gtrsim 0.9$, and a DM-core class at $f_\text{DM} \lesssim 0.02$. The two classes can be separated by the surface redshift of the normal matter, which reaches $z=0.73$–$0.77$ for the DM-core class and stays below $0.45$ for the DM-halo class. Finally, we find hybrid star solutions of 'ultimate twins' with similar mass and visible radius, but different dark matter content, leading to different tidal deformabilities and surface redshifts. Future X-ray and gravitational measurements of ultra-compact neutron stars with radii and masses outside the allowed neutron star range can thereby probe the presence and the properties of DM in addition to a first-order phase transition to quark matter.

Background: The quasiparticle random-phase approximation (QRPA) within nuclear density functional theory provides a powerful framework for describing collective excitations. Although the finite-amplitude method (FAM) efficiently solves the QRPA problem, repeated calculations for different external-field parameters remain computationally demanding. Purpose: We construct a reduced basis method (RBM)-based emulator for the FAM that treats the complex energy of the external field as a model parameter to efficiently reproduce FAM amplitudes and QRPA eigenmodes. Methods: High-fidelity FAM calculations are performed at a small set of training points in the complex-energy plane. The resulting FAM amplitudes form a non-orthogonal reduced basis. A variational equation yields an emulator that can predict the response at arbitrary complex energies and QRPA eigensolutions without additional full FAM calculations. Results: The RBM emulator accurately reproduces FAM strength distributions in both giant-resonance and low-energy regions when the relevant energy domain is covered by the training set. It also reproduces imaginary QRPA modes associated with shape instabilities of the HFB state. Applied to the $K^\pi=0^+$ mode of rare-earth Dy isotopes in a realistic model space, the emulator reproduces strength distributions and the lowest $0^+$ collective states with precision comparable to full FAM calculations, reducing the computational cost by more than an order of magnitude. Conclusions: The RBM provides an efficient and accurate FAM emulator. Its ability to reproduce giant-resonance, low-energy, and imaginary-energy modes at drastically reduced computational cost makes it promising for density-functional optimization, calculations of collective inertia, and large-scale surveys of nuclear collective excitations.

Recently, Sobhani and Luo \cite{sobhani2025unified} proposed a new empirical formula for $\alpha$ decay based on the $Q_\alpha^{-1/4}$ energy dependence, incorporating the proton number $Z$, neutron number $N$, and relative neutron excess $I = (N - Z)/(N + Z)$ as primary parameters. In this work, we extend this model by explicitly including the angular momentum of the emitted $\alpha$ particle and the quadrupole deformation of the daughter nucleus. Using this improved formula to evaluate the $\alpha$-decay half-lives of 400 nuclei yields a root-mean-square (RMS) deviation of 0.97 relative to experimental data. Furthermore, we employ support vector regression (SVR)-taking $Q_\alpha^{-1/4}$, $N$, $Z$, angular momentum, and daughter-nucleus deformation as input features-which further reduces the RMS deviation to 0.56. Finally, we apply both the extended formula and the SVR model to predict the $\alpha$-decay half-lives of even-even nuclei with $Z = 120$ and $Z = 122$. The predicted half-lives show good consistency with those from the Sobhani and Poenaru formulas, and both approaches strongly support $N = 184$ as the next neutron magic number.

The symmetry-conserving density functional theory (DFT)-based no-core configuration-interaction (DFT-NCCI) framework is applied for the first time to investigate the impact of configuration interaction (CI) on the Coulomb (isospin) impurity, $\alpha_{\rm C}$, in the ground and excited states of $^{10}$C, $^{10}$B, and $^{14}$N, as well as on the isospin-symmetry-breaking (ISB) correction to the superallowed $0^+ \rightarrow 0^+$ $\beta$ decay of $^{10}$C. We demonstrate, among other findings, that within the DFT-NCCI framework CI has a negligible effect on the ground-state isospin impurities, which are dominated by a single doorway state. In contrast, CI significantly modifies the impurities in excited states, including the isobaric analogue $I=0^+,\,T=1$ state in $^{10}$B. Hence, it also has a non-negligible impact on the ISB correction to the superallowed $\beta$ decay of $^{10}$C. Our calculations yield $\bar{\delta}_{\rm C}=0.45(4)\%$ when the Coulomb interaction is taken as the sole source of ISB, and $\bar{\delta}_{\rm ISB}=0.46(6)\%$ when short-range charge-symmetry-breaking (CSB) terms are included in addition. Hence, no statistically significant dependence of the ISB correction on the short-range CSB interaction is observed for this decay. Comparison with our previous results reveals a strong sensitivity to the nuclear symmetry energy, which governs the strength of the isospin-restoring force and whose value in finite nuclei remains difficult to constrain because of its intricate dependence on the momentum-dependent terms of the effective interaction.

The production of light nuclei in relativistic heavy-ion collisions provides valuable insights into the dynamics of the hot and dense matter created in these extreme environments. While stable light nuclei have been extensively studied, unstable light nuclei being short-lived resonance states remain largely unexplored and offer unique opportunities to probe final-state interactions and the freeze-out conditions. In this paper, we propose a partial-wave method, based on the Lednický–Lyuboshitz framework, to extract resonance signals of unstable light nuclei from two-particle correlation functions measured in heavy-ion collisions. By extending the LL model to higher order partial waves and directly incorporating experimental phase-shift data from low-energy nuclear scattering, our approach avoids the need for model-dependent potential parametrizations and enables a clean decomposition of the resonant partial wave from the non-resonant background. As a demonstration, we apply the method to the $p$-$^3$He and $p$-$^4$He systems, corresponding to the $^4$Li and $^5$Li ground-state resonances. Numerical results show that the resonance-induced correlation excess can be effectively isolated, with a peak in the correlation function appearing at $k \approx 72$ MeV/$c$ for $^4$Li and $k \approx 50$ MeV/$c$ for $^5$Li, consistent with the known resonance parameters. The extracted transverse momentum spectra and rapidity distributions are presented using the measured proton and light-nuclei spectra from STAR at $\sqrt{s_{NN}} = 3$ GeV. The proposed method provides a practical tool for the experimental study of unstable light nuclei in relativistic heavy-ion collisions and can be extended to a broader range of resonance states.

We develop CGC-py, a Monte Carlo event generator for deep-inelastic scattering. It couples the full Color Glass Condensate (CGC) cross section for $\gamma^*p(A)\to q\bar q+X$ to a Parton-Branching transverse-momentum-dependent backward initial-state shower, while Pythia~8 handles final-state radiation and hadronization. CGC-py retains the complete target-elastic and target-inelastic contributions without taking the back-to-back correlation limit, allowing single- and di-hadron observables to be generated consistently from the same event sample. We validate the generator through an analytic closure test of the single-inclusive quark spectrum and a comparison of charged-hadron spectra in $ep$ collisions with H1 data, finding excellent agreement. The predicted nuclear modification factor $R_{e\mathrm{Au}}^h$ shows the expected saturation pattern: suppression at low $p_T^*$ followed by a rise toward unity at higher $p_T^*$. A comparison with a Pythia~6 baseline, together with an $x_g$-rescaling study, indicates that small-$x$ CGC evolution and collinear DGLAP dynamics contribute comparably to the growth of the dihadron away-side width with energy. Genuine saturation-driven broadening emerges only at the highest energies considered. Within CGC-py, $e\mathrm{Au}$ collisions exhibit an enhanced away-side width and a suppressed back-to-back yield relative to $ep$ collisions. These nuclear effects remain modest over EIC kinematics, motivating measurements at the most forward accessible kinematics and the use of complementary observables to maximize sensitivity to gluon saturation.

Quantum computers promise advantages for simulating strongly correlated quantum many-body systems, like atomic nuclei, that are beyond the reach of classical computers. Realizing this potential requires understanding the quantum complexity structure of the target problem. We investigate the time-evolution of two key indicators of quantum complexity, bipartite entanglement entropy and non-local magic (non-stabilizerness), in nuclear reaction dynamics. We analyze two representative dynamical processes: scattering in a one-dimensional model of strongly interacting fermions governed by the Negele potential, and a realistic simulation of $^{240}$Pu fission within time-dependent Hartree-Fock-Bogoliubov (TDHFB) theory. In the former case, we find that interactions dynamically generate both entanglement and non-local magic, leaving persistent signatures of quantum complexity in the outgoing states. In the latter, we observe that substantial quantum complexity survives in the spatial bipartition of daughter fragments well beyond scission. The presence of significant non-local magic and entanglement in both cases strongly indicate that quantum computers would provide substantial advantages for accurately simulating nuclear reaction dynamics.

We investigate the projective and resurgent structure of a spin hydrodynamic attractor in Bjorken expansion. We show that the nonlinear spin solution family is determined by the projective classes of the two dimensional linear solution space, with the attractor and repellor corresponding to two distinguished projective directions and the linear modes ratio generating the full one-parameter transseries tower. Using the projective transseries structure, we show analytically that the data of repellor are encoded in the Borel-Stokes structure of the attractor expansion. These results provide an explicit analytic realization of resurgence relations that are often extracted through high order expansions and numerical Borel analysis, and yield a unified description of the attractor, the repellor, and their Borel-Stokes connection in minimal causal spin hydrodynamics.

The "left-hand cut problem" in lattice QCD arises when exchange singularities invalidate standard relations used to extract scattering amplitudes from the finite-volume spectrum. In recent years, several approaches were proposed to resolve this problem. We establish analytically and verify numerically the equivalence between the three-body approach proposed in [JHEP 06 (2024) 051] and the two-body left-hand cut formalism developed in [JHEP 08 (2024) 075]. We test the equivalence in a scalar model describing a particle scattering from an $S$-wave two-particle bound state through one-particle exchange. Both approaches reproduce the same infinite-volume particle–bound-state amplitude and correctly encode the associated left-hand cut in the finite-volume spectrum. Crucially, we identify that the exponentially suppressed finite-volume effects neglected in both formalisms can be numerically large, compromising amplitude extraction at small lattice volumes.

Halo nuclei are exotic nuclei, which exhibit a much larger matter radius than their isobars. This unusual size is now understood as a threshold effect, in which one or two valence nucleons are loosely bound to the core of the nucleus. Thanks to this loose binding, halo nuclei exhibit a strongly clusterised structure with a diffuse neutron halo surrounding a compact core. Being short lived, halo nuclei are mostly studied through reactions, such as breakup. In this talk we show that including Halo Effective Field Theory within existing reaction codes is both effective and efficient to analyse experimental data. We first apply this idea to study the Coulomb breakup of 19C within a Bayesian approach. Second, we extend Halo-EFT to include the core's excitation to test the sensitivity of the Coulomb breakup of 11Be on spectroscopic factors.

The equilibrium abundances of the light clusters $^2$H, $^3$H, $^3$He, $^4$He in hot nuclear matter at densities near the saturation density are of essential interest for nuclear physics and astrophysical applications, but theoretical approaches give diverging answers. We compare the quantum statistical approach with the recently discussed phase-space excluded-volume approach. We analyze the main ingredients, the Mott momentum, and the momentum distribution functions of light clusters. We observe a sharp decrease in cluster abundances as the density approaches saturation density, that is also seen in a relativistic mean-field calculation. We outline possible improvements in determining the composition of hot, dense matter in thermodynamic equilibrium. Non-equilibrium effects must be taken into account to investigate cluster formation in heavy-ion collisions.

We investigate the effects of strong magnetic fields on the equation of state (EoS) and stellar structure of cold, charge-neutral, $\beta$-equilibrated hyperonic neutron-star matter within a relativistic mean-field (RMF) framework. The matter sector contains the full baryon octet and leptons, while charged particles are Landau quantized and all baryons are coupled to the magnetic field through their anomalous magnetic moments (AMM). The calculation is performed with the RMF FSU2H hyperonic parameterization and compared for zero field, constant magnetic fields, and density-dependent magnetic-field profiles. We find that strong magnetic fields modify the hyperonic composition through the competing effects of Landau quantization and AMM-induced spin splitting. Landau quantization softens the magnetized hyperonic equation of state. The inclusion of AMM provides an additional magnetic stiffening mechanism in hyperonic matter. The results for the inclusion of the AMM coupling and not are still consistent with observations of $2.00$-$2.02\,M_{\odot}$ neutron stars and small radii. The present work therefore provides a benchmark for assessing the influence of AMM on the composition, magnetization, equation of state, and mass-radius structure of magnetized hyperonic neutron-star matter.

Gluon saturation produces characteristic transverse-momentum broadening in nuclei, but QCD radiation largely washes out this signature. We show that fiducial recoil subtraction turns detector acceptance into a transverse-momentum projector that unmasks the broadening in forward $Z^0$ production. Subtracting the hadronic recoil measured in a chosen rapidity interval from the boson transverse momentum defines a residual momentum. At leading power, the radiative recoil in this interval cancels, while the residual momentum retains sensitivity to the small-$x$ nuclear field. Combining a CGC description of the small-$x$ target with soft-collinear effective theory (SCET) resummation for finite rapidity coverage, we find that a benchmark rapidity coverage $|\eta^{\rm lab}|<2.5$ lowers the effective hard scale from $M_Z\simeq 91.2$ GeV to about $7.5~\mathrm{GeV}$ of the Sudakov evolution. Increasing the saturation scale broadens the residual-momentum distribution and weakens recoil alignment, whereas wider coverage makes the proton–nucleus separation clearer in both observables. Detector geometry thus provides tunable control over perturbative recoil, enabling a probe of nonlinear small-$x$ QCD.

Electromagnetic fields produced in relativistic heavy-ion collisions depend sensitively on the initial spatial distribution of nuclear charge. Using the Liénard–Wiechert potential with a triaxially deformed Woods–Saxon density, we calculate the transverse electric and magnetic field distributions in $^{129}\mathrm{Xe}+{}^{129}\mathrm{Xe}$ collisions at $\sqrt{s_{NN}}=5.44\text{ TeV}$. We systematically examine how the triaxiality angle $\gamma$ modifies the field structure at the collision time ($t=0$) in semi-central events, using spherical nuclear collisions as a baseline. The results show that nuclear triaxiality causes distinct spatial redistributions of both electric and magnetic fields in the transverse plane. These findings indicate that initial electromagnetic fields encode key information on intrinsic nuclear shapes, offering an additional constraint on nuclear deformation and its consequences for field-sensitive observables in heavy-ion collisions.

In this mini-review, we provide a brief status report on investigating spin transport phenomena in intermediate-energy heavy-ion collisions by simulating solutions of the spin- and isospin-dependent Boltzmann-Uehling-Uhlenbeck (SIBUU) transport equation using the test-particle method. We outline the physics foundation and technical approach, summarize our main results and identify key challenges in further studying spin transport within the SIBUU framework. As examples, we show how the global and local spin polarizations of nucleons, the spin splitting of nucleon collective flows as well as flows of light clusters at different spin states can be used to explore interesting new physics associated with the nuclear spin-orbit potential in dense neutron-rich medium. The spin-orbit potential and the rigorous angular momentum conservation are also shown to affect spin-averaged observables. Hopefully the new findings and challenges identified here will stimulate further studies both theoretically and experimentally on spin transport in intermediate-energy heavy-ion collisions.

Fluctuations of conserved charges are a primary tool in the search for the QCD critical endpoint, but their beam-energy dependence is complicated by global baryon-number conservation, whose influence changes as the experimental acceptance covers different fractions of the collision system. We propose using correlations of net-baryon fluctuations between two separated rapidity windows to exploit the distinct signatures of conservation and critical dynamics. Global conservation produces a negative cross-window correlation, whereas a common long-wavelength critical fluctuation produces a positive one. We show that, within a canonical independent-source framework, the conservation-induced background and the critical signal enter additively at leading order, allowing the leading conservation term to be estimated and subtracted. The resulting yield-scaled correlator follows the nonmonotonic enhancement of an Ising-mapped equilibrium correlation length along a freeze-out trajectory passing near a hypothetical critical endpoint, while wider rapidity windows reduce the response through thermal smearing. Cross-rapidity cumulants therefore provide a rapidity-differential strategy for reducing the leading conservation background and sharpening fluctuation-based searches for QCD criticality in beam-energy-scan experiments.

Advances in several physics domains open up novel paths to smaller scale, higher energy density opportunities to advance small systems for nuclear fusion. Here we survey both legacy and several novel “table-top” approaches which attract current interest. We furthermore address a few related practical and challenging nuclear science topics arising in the context of magnetic confinement and inertial confinement fusion. The contents emphasis includes: By example of solar fusion cycles we draw attention to aneutronic fusion reaction chains. Considering the natural isotopic abundances we assess more carefully the meaning of the term “limitless energy” in the context of actual fusion power realizations. We describe achievements in laser-driven proton-boron fusion, and extensions to a self-sustaining and nearly fully aneutronic proton-boron-nitride reaction cycle. We propose another aneutronic option, where the target is a mix of beryllium and light helium isotope; this 3-helium is arguably the most mentioned fusion component in this article. We look in depth at the plasmonic opto-electric field-enhancement for fusion, and at the particle (muon) catalyzed fusion option. We describe problems in harnessing the dt fusion for civilian use. We introduce space travel as forthcoming application of aneutronic fusion.

Predictions for the systematics of low-lying states in neutron-rich $N=50$ isotones from \nuclide[80]{Zn} to \nuclide[70]{Ca}, where experimental information remains scarce, exhibit substantial model dependence. We investigate these nuclei using multi-reference covariant density functional theory based on a relativistic energy density functional, in which nuclear wave functions are constructed as superpositions of symmetry-restored mean-field states with different quadrupole deformations. The low-lying states of \nuclide[78]{Ni} are reasonably reproduced, and a prolate rotational band built on the second $0^+$ state is predicted in addition to a near-spherical ground state. As the proton number decreases toward $Z=20$, the low-energy structure exhibits a nonmonotonic evolution from spherical to strongly deformed and subsequently back to spherical shapes, consistent with valence-space shell-model predictions. In particular, the emergence of deformed ground states in \nuclide[76]{Fe} and \nuclide[74]{Cr} is accompanied by enhanced quadrupole collectivity and stronger shape mixing. The results provide a coherent microscopic description of the structural evolution from the doubly magic \nuclide[78]{Ni} to the neutron-rich $N=50$ isotones.

The extraction of the nuclear surface diffuseness from relativistic heavy ion collisions is limited by the intertwined responses of geometry-driven observables to surface diffuseness and intrinsic nuclear deformation. We investigate this limitation using event-by-event Monte Carlo Glauber simulations, focusing on the sensitivity of multiparticle correlations to the Woods–Saxon surface diffuseness $a_0$ in intrinsically deformed nuclei. We systematically examine the local correlations between $a_0$ and quadrupole and octupole deformation parameters, $\beta_2$ and $\beta_3$, and determine how these correlations affect the ability of different observables to constrain $a_0$. We find that observables dominated by elliptic geometry exhibit a strong response to quadrupole deformation, leading to a local $a_0$–$\beta_2$ degeneracy that substantially limits their sensitivity to the nuclear surface diffuseness. Triangular correlations provide a more independent response to the nuclear surface and therefore retain additional information on $a_0$, although their sensitivity can also be modified by intrinsic deformation. Extending the analysis to simultaneous quadrupole and octupole deformation shows that the local degeneracy and least-constrained directions depend on the nuclear configuration, demonstrating that the limitation on extracting $a_0$ is not described by a single global parameter correlation. We quantify these effects using multidimensional response maps, local sensitivity and information-geometric measures, and a Bayesian analysis of the resulting parameter constraints. The results clarify the fundamental limitations imposed by intrinsic multipole deformation on the determination of nuclear surface diffuseness from relativistic heavy ion collisions and identify multiparticle correlations that provide more independent information on $a_0$.