We calculate the number of virtual photons for Coulomb dipole excitation (CDE; $l=1$), Coulomb quadrupole excitation (CQE; $l=2$), and Coulomb magnetic excitation (CME; $l=1$) in the ${}^8\mathrm{B}+ {}^{208}\mathrm{Pb}$ system at a laboratory energy of $E_{\text{lab}}=83$ MeV/nucleon. Virtual photon counts are obtained using both general and relativistic methods for CDE, CQE, and CME. For the CDE, the number of virtual photons obtained using the general method is highly consistent with that derived using the relativistic method. In contrast, the CQE analysis reveals a marginal discrepancy between the two methods. Nonetheless, when retardation effects are included in the general method, the differences became negligible. The heuristically derived nonrelativistic expression matches the general method at low energies, and consistency among all three approaches (CDE, CQE, and CME) is achieved only under the simultaneous conditions $\gamma \to$ 1, $\varepsilon \to$ 1, and $\zeta \to$ 0. Subsequently, employing the virtual photon numbers and Coulomb dissociation cross sections, we compute the Coulomb strength distributions for CDE, CQE, and CME. The peak of the Coulomb strength distribution for CDE analysis demonstrates that Coulomb excitation-induced breakup reactions are more significant in neutron-rich nuclei than in proton-rich nuclei. Using the Coulomb electric dipole strength distributions, we calculate the imaginary CDE potential.

From simple symmetry and energy considerations it can be concluded that ${}^{98}\mathrm{Tc}$ might undergo electron capture decay (EC). In this work we provide evidence for an EC decay of ${}^{98}\mathrm{Tc}$ measuring 2.67 g $\mathrm{K}\left[\mathrm{Tc}{\mathrm{O}}_4\right]$ that contains approximately 1 GBq of ${}^{99}\mathrm{Tc}$. By use of a lead shielding for the sample, it was possible to identify the coincident $4+\to 2+$ and $2+\to 0+\gamma$ transitions in the daughter nuclide ${}^{98}\mathrm{Mo}$ at the University of Cologne's Cologne Clover Counting setup of the Institute for Nuclear Physics. For the first time, the EC/${\beta }^{-}$ branching ratio of 0.29(3)% was determined directly. With a $logft$ of 14.21(7) this decay does almost tie with the $logft$ of the ${}^{36}\mathrm{Cl}$ EC decay [14.23(1)] for the same highest second forbidden nonunique transition.

Nuclear level density (NLD) parameters for the constant temperature and back-shifted Fermi gas models were determined for 129 nuclei, spanning from ${}^{43}\mathrm{Sc}$ to ${}^{243}\mathrm{Pu}$. These parameters were extracted using a Bayesian optimization technique by fitting the experimentally measured NLD data obtained from the Oslo method and particle evaporation experiments. For each model, the extracted NLD parameters were further fitted using various functional forms, leading to the identification of optimal expressions based on fractional root-mean-square deviations. The resulting expressions reveal that the NLD parameters primarily depend on three key quantities: the mass number, shell correction energy, and deuteron pairing energy. The accuracy and reliability of these optimized formulations were assessed by comparing the predicted values with measured neutron resonance spacing data. This validation confirms their effectiveness in describing NLDs across the nuclear chart, capturing the signatures of nuclear magicity and deformation.

A weak dependence of the angular momentum of ${}^{144}\mathrm{Ba}$ fragments, produced in the spontaneous fission of ${}^{252}\mathrm{Cf}$, on the total kinetic energy (TKE) was recently observed [N. P. Giha et al., Phys. Rev. C 111, 014605 (2025)]. To investigate this phenomenon, we propose a model describing the evolution of the fissioning nucleus toward scission. The model assumes that, after tunneling through the fission barrier, the nucleus can be represented by a superposition of dinuclear systems (DNSs). We calculate main fission observables, including mass, TKE, and neutron multiplicity distributions, and compare them with experimental data. The angular motion in the DNS is treated quantum-mechanically, yielding the angular momentum distribution of DNS nuclei at scission configurations leading to ${}^{144}\mathrm{Ba}$ fragments. Within this framework, we successfully reproduce and explain the experimentally observed dependence of the average angular momentum of ${}^{144}\mathrm{Ba}$ on TKE.

A new technique is presented for measuring the half-lives of resonances in the picosecond range using presently available invariant-mass apparatus and a thick target. For short-lived resonances, the energy losses of the decay fragments in the target material change their relative velocities, giving rise to a poor invariant-mass resolution. However, for longer-lived resonances that travel through the remaining target material before decaying outside of the target, this dominant contribution to the resolution is eliminated. The measured invariant-mass peak will then display a narrow peak from these events which sits on a wider structure associated with the remaining events that decay in the target. The fraction of the events in the narrow peak is related to the probability that the resonance leaves the target before decaying and hence is related to the lifetime. This technique is exercised for the 2.685-MeV resonance in ${}^{33}\mathrm{Cl}$ which decays by emitting an $f$-wave proton. A half-life of $T_{1/2}=5.7_{-2.5}^{+4.1}$ ps was measured, which is consistent with values inferred from other known properties of this resonance.

The effects of the deuteron breakup are estimated for the $\mathrm{\Lambda }$-deuteron momentum correlation function. Faddeev amplitudes in calculating low-energy $\mathrm{\Lambda }$-deuteron scattering can provide not only the elastic scattering part but also breakup wave functions in the incident and the rearrangement channels. Calculations are carried out using nucleon-nucleon (NN) and hyperon-nucleon (YN) interactions parametrized in chiral effective field theory. The effects of the breakup in the incident channel are found to be marginally insignificant. Those of the rearrangement channel are not negligible, but not large when the source radius is larger than 2.5 fm. Nevertheless, it is worthwhile to have the information on the magnitude of these effects when analyzing the experimental data.

Background: The $\beta$-decay half-lives of nuclei are sensitive to the values of $Q_{\beta }$. For accurate theoretical predictions, it is essential to develop an effective interaction or an energy-density functional (EDF) that can systematically reproduce experimental $Q_{\beta }$ values. However, it remains unclear which nuclear bulk properties are most relevant for constraining $Q_{\beta }$ predictions.

Purpose: The aim of this work is to identify the nuclear bulk properties that are strongly correlated with $Q_{\beta }$ values, thereby clarifying the key nuclear characteristics that govern $\beta$-decay calculations.

Method: We employ the Skyrme energy-density functionals to find correlations between $Q_{\beta }$ and the nuclear bulk properties, assuming spherical symmetry. Using 42 different Skyrme EDFs, we analyze these correlations by evaluating Pearson linear coefficients, focusing particularly on the relationship between $Q_{\beta }$ and various nuclear properties.

Results: The analysis shows that the symmetry energy at low densities exhibits a significant correlation with $Q_{\beta }$. This correlation becomes stronger for functionals with an effective mass close to 1, but it weakens at higher nuclear densities.

Conclusions: From our analysis, we found that a symmetry energy of $32.8\pm 0.7\mathrm{MeV}$ and effective mass of $m^{*}/m\ge 0.75$ at the saturation density is the most likely to reproduce the experimental data of $Q_{\beta }$ systematically.

The possible antimagnetic rotation (AMR) of the four negative-parity yrast bands with four $g_{9/2}$ valence proton holes in the isotopes ${}^{103,105,107,109}\mathrm{Pd}$ is systematically investigated by using the cranked shell model with pairing correlations taken into account by a particle-number-conserving treatment. The calculated values of $B(E2$) after backbending agree well with the available experimental data, which display decreasing tendency with the rotational frequency. The two-shears-like mechanism is clearly exhibited in the case of four valence proton holes. Accordingly, we verify the AMR properties of the ${}^{103}\mathrm{Pd}$ negative-parity yrast band recognized previously in the literature, and suggest the negative-parity yrast bands of ${}^{105,107,109}\mathrm{Pd}$ as three new candidates for an AMR band, thereby extending the Pd isotope chain with AMR by four mass units towards the neutron-rich side.

Background-free inelastic-scattering spectra were measured for even-$A$ neodymium (Nd) isotopes using a halo-free 386-MeV $\alpha$ beam at forward angles, including $0^{\circ }$, to examine the influence of deformation on isoscalar giant resonances. The strength distributions of isoscalar giant resonances (with multipolarity $L\le 3$) in ${}^{142}\mathrm{Nd}$ and ${}^{146-150}\mathrm{Nd}$ isotopes are determined using multipole decomposition analysis. This analysis is based on angular distributions calculated within the framework of the distorted-wave Born approximation with transition densities generated with a Woods-Saxon type potential. The isoscalar giant monopole resonance exhibits a distinct splitting into low-energy and high-energy components while going from the spherical nucleus ${}^{142}\mathrm{Nd}$ to the well-deformed nucleus ${}^{150}\mathrm{Nd}$ due to coupling with the $K=0$ component of the isoscalar giant quadrupole resonance (ISGQR). The isoscalar giant dipole resonance displays a bimodal structure, with an evidence of coupling between the dipole ($E1$) and high-energy octupole ($E3$) resonance due to deformation effects. The ISGQR splits into distinct $K$ components ($K=0$, 1, and 2) due to deformation. A signature of an overtone mode in ISGQR at an energy around 26 MeV has been obtained.

Although it is known that the $N=28$ spherical shell closure erodes, the strength of the closure with decreasing proton number $Z<20$ is an open question in nuclear structure. In this region of interest, high-precision mass measurements of neutron-rich ${}^{43-45}\mathrm{Cl}$ isotopes were performed at the Low Energy Beam and Ion Trap when coupled to the National Superconducting Cyclotron Lab. The resulting mass excesses (MEs) are $\mathrm{ME}\left({}^{43}\mathrm{Cl}\right)=-24114.4\left(1.7\right)\mathrm{keV}, \mathrm{ME}\left({}^{44}\mathrm{Cl}\right)$ = −20 450.8(10.6) keV, and $\mathrm{ME}\left({}^{45}\mathrm{Cl}\right)=-18240.1\left(3.7\right)\mathrm{keV}$, and the uncertainty of these masses is improved by up to a factor of $\sim 40$ compared to the previous values reported in the 2020 Atomic Mass Evaluation. Comparison to ab initio calculations using the Valence-Space In-Medium Similarity Renormalization Group shows good agreement up to and including the closure.

Actinide nuclei exhibit mass-asymmetric fission at low energy due to shell structure. The fission-fragment mass distributions produced at high energy tend to have a symmetric shape due to smearing of shell effects. On the other hand, the distribution can be changed by neutron emission occurring before fission, as this decreases the excitation energy of the fissioning nucleus, and thus revives the shell structure. In so-called multichance fission, neutron emission is considered prior to fission at the initial nuclear shape, and competition between fission and neutron emission is determined with the framework of the statistical model. In the present work, we describe fission in the Langevin equations, and neutron emission is treated throughout the fission process. The calculation reproduces experimentally observed mass distributions, for a wide range of initial compound-nucleus excitation energy up to 60 MeV. The results show that, while neutron emission dominates at the ground-state shape, it occurs along the shape evolution path to the scission point.

The empirical systematics of long-range $\alpha$-particle emission probabilities $P_{\mathrm{LRA}}$ are investigated in spontaneous and thermal-neutron-induced fission of heavy and superheavy nuclei. The correlations between $P_{\mathrm{LRA}}$ and various parameters, including the fissility $Z^2/A$, the linear combination of proton and mass numbers $4Z-A$, and the release energy $Q_{\alpha }$ of $\alpha$ decay are studied. A new semiempirical formula for $P_{\mathrm{LRA}}$, expressing it as a linear function of $Q_{\alpha }$, is proposed and its predictive power is compared with existing empirical and semiempirical formulas. The influence of experimental data uncertainties on the fitting results is shown. The values of $P_{\mathrm{LRA}}$ are predicted for neutron-deficient nuclei and superheavy nuclei. The approach was extended to describe the emission of light charged particles and clusters in both spontaneous and thermal-neutron-induced fission of heavy and superheavy nuclei.

Nuclear matrix elements (NMEs) for neutrinoless $\beta \beta$ decays and inverse-$\beta$ decays are crucial for studying $\nu$ properties beyond the standard model and astro-$\nu$ nuclear interactions. The NMEs consist mainly of the isospin ($\tau$) spin ($\sigma$) component, and the $\tau \sigma$ strength (square of the $\tau \sigma$ NME) is studied experimentally by charge exchange reactions (CERs). The summed Gammow-Teller ($\tau \sigma$) and spin dipole ($\tau \sigma Y_1$) strengths measured by CERs are shown to be reduced half with respect to the nucleon-based sum-rule limits. The $\tau \sigma$ NMEs are shown to be quenched due to the non-nucleonic $\mathrm{\Delta }$-isobar resonance effect on the basis of the measured strengths and the quasiparticle random-phase approximation analysis with effective nucleon-nucleon and $N\mathrm{\Delta }$ $\tau \sigma$ interactions. The quenching effect is incorporated by using an effective $\tau \sigma$ coupling of $g_{\tau \sigma }^{\mathrm{\Delta }}/g_{\tau \sigma }$ $\approx 0.7$ with $g_{\tau \sigma }$ being the coupling for a free nucleon. The quenching effect is applied to the $\tau \sigma$ components of the weak, electromagnetic and nuclear interaction NMEs. Impact of the $\mathrm{\Delta }$-resonance effect on $\nu$ studies in nuclei is discussed.

The possible bound state of the $\varphi N\text{−}\alpha$ system is explored within the framework of the three-body cluster model. The calculations are done by employing the state-of-the-art $\varphi N$ interactions obtained from the analysis of the pure elastic scattering and the coupled-channel in the $\varphi p$ correlation functions. The $\varphi \alpha$ potentials are constructed by two methods: the single-folding potential (SFP) method for the given spin-averaged $\varphi N$ potentials in coordinate space, and the optical-model potential (OMP) approximation within the multiple-scattering framework for the given scattering length of the $\varphi N$ interaction. It is found that, when only the single-channel $\varphi N$ interactions are employed, the $\varphi N\text{−}\alpha$ system could be bound with a binding energy in the interval [3–26] MeV. However, the coupled-channel $\varphi p$ interaction, which is most consistent with experimental measurements, does not yield any bound state, even when the spin-averaged $\varphi N$ potential is employed, and this potential is found to be more attractive than the corresponding coupled-channel counterpart. It is essential to consider the contributions from the dynamics of the vector-baryon coupled channels $\varphi p$ interaction. This effect is capable of playing a decisive role in the existence of mesic nuclei.

Toward an improved understanding of the role of quantum information in nuclei and exotic matter, we examine the quantum magic (nonstabilizerness) in low-energy strong interaction processes. As stabilizer states can be prepared efficiently using classical computers, and include classes of entangled states, it is quantum magic and fluctuations in quantum magic, together with entanglement, that determine computational resource requirements. As a measure of fluctuations in quantum magic, and hence the severity of the exponentially scaling classical computing resource requirements, induced by scattering, the “magic power” of the $S$-matrix is introduced. This provides indirect experimental constraints on quantum resources required to model nuclei and dense matter using fault-tolerant quantum computers. Using experimentally determined scattering phase shifts and mixing parameters, the magic power in nucleon-nucleon and hyperon-nucleon scattering, along with the magic in the deuteron, are found to exhibit interesting and distinct features. The ${\mathrm{\Sigma }}^{-}$-baryon is identified as a potential candidate catalyst for enhanced spreading of magic and entanglement in dense matter, depending on in-medium decoherence.

The high spin excited states of Lanthanum isotopes ${}^{140\text{–}143}\mathrm{La}$, above the $N=82$ closed shell, were populated in fission reactions. The prompt $\gamma$-ray transitions were measured using two complementary methods: (a) in coincidence with the isotopically identified fragments produced in the fission of the ${}^{238}\mathrm{U}+{}^9\mathrm{Be}$ system using the Variable Mode Spectrometer ($\mathrm{VAMOS}++$) and the Advanced Gamma Tracking Array (AGATA) spectrometer, and (b) high statistics threefold $\gamma \text{−}\gamma \text{−}\gamma$ and fourfold $\gamma \text{−}\gamma \text{−}\gamma \text{−}\gamma$ coincidence data from the spontaneous fission of ${}^{252}\mathrm{Cf}$ using the Gammasphere. This work reports the first identification of a pair of parity doublet structures in ${}^{143}\mathrm{La}$ and the new high spin level structure in ${}^{140\text{–}142}\mathrm{La}$ from prompt $\gamma$-ray spectroscopy. The level structures are interpreted in terms of the systematics of neighboring odd-$Z$ nuclei above the $Z=50$ shell closure and large-scale shell model calculations. The present results indicate the presence of stable octupole deformation in ${}^{143}\mathrm{La}$. The excitation energy pattern and their comparison with neighboring isotones, moving away from the $N=82$ closed shell, point towards a transition from single-particle structures to an alternating parity rotational band structure in the La isotopic chain.

Using the beyond-Skyrme-Hartree-Fock approach with various Skyrme-type $NN$ effective interactions, we explore the large spectroscopic quadrupole moment $Q_s$ of the first excited $2_1^{+}$ state in ${}^{20}\mathrm{Ne}$. Our calculated $Q_s\left(2_1^{+}\right)\approx -0.20e\text{b}$ aligns closely with the experimental value of $-0.22\left(2\right)e\text{b}$. Consistent with other theoretical methods, our results confirm the presence of an $\alpha$ cluster structure in this state. We also investigate the robustness of the $\alpha$ cluster against tensor force, demonstrating that incorporating tensor components significantly enhances $Q_s\left(2_1^{+}\right)$ and strengthens the cluster structure along the symmetrical axis.

Based on the quasiparticle random-phase approximation implemented via the finite-amplitude method, we employ a set of representative relativistic mean-field models to investigate the sensitivity of the inverse electric-dipole polarizability $1/{\alpha }_{\mathrm{D}}$ in ${}^{48}\mathrm{Ca}$, ${}^{68}\mathrm{Ni}$, and ${}^{208}\mathrm{Pb}$ to the symmetry energy $E_{\mathrm{sym}}\left(\rho \right)$ and the neutron matter equation of state $E_{\mathrm{PNM}}\left(\rho \right)$ at a subsaturation density of $\rho ={\rho }_0/3$, with ${\rho }_0$ being the saturation density. Combined with predictions from nonrelativistic Skyrme energy-density functionals (EDFs), our results reveal strong linear correlations between $1/{\alpha }_{\mathrm{D}}$ and both $E_{\mathrm{sym}}({\rho }_0/3)$ and $E_{\mathrm{PNM}}({\rho }_0/3)$. In particular, the $1/{\alpha }_{\mathrm{D}}-E_{\mathrm{PNM}}({\rho }_0/3)$ correlation for ${}^{208}\mathrm{Pb}$ is found to be nearly model independent. A Bayesian analysis of the measured values of ${\alpha }_{\mathrm{D}}$ in ${}^{48}\mathrm{Ca}$, ${}^{68}\mathrm{Ni}$, and ${}^{208}\mathrm{Pb}$ yields quantitative constraints of $E_{\mathrm{sym}}({\rho }_0/3)=17.8_{-0.9\left(1.6\right)}^{+1.1\left(1.8\right)}\mathrm{MeV}$ and $E_{\mathrm{PNM}}({\rho }_0/3)=9.1_{-0.9\left(1.4\right)}^{+0.8\left(1.4\right)}\mathrm{MeV}$ at the 68% (90%) confidence level, respectively. The extracted value of $E_{\mathrm{PNM}}({\rho }_0/3)$ exceeds most predictions from microscopic many-body theories, suggesting a mild tension between nuclear EDF-based constraints derived from ${\alpha }_{\mathrm{D}}$ data and results from ab initio calculations.

The unbound nucleus ${}^7\mathrm{He}$ was recently studied in the ${}^2\mathrm{H}({}^6\mathrm{He},{}^1\mathrm{H}){}^7\mathrm{He}$ reaction at 29 $A\mathrm{MeV}$ beam energy by Golovkov et al. [Phys. Rev. C 109, L061602 (2024)]. The excitation spectrum of ${}^7\mathrm{He}$ was measured up to $E_T=8$ MeV ($E_T$ is energy above the ${}^6\mathrm{He}\text{−}n$ threshold). Angular distribution for the ${}^6\mathrm{He}\text{−}n$ decay of the ${}^7\mathrm{He}3/2^{-}$ ground state can be explained by a strong spin alignment induced by a reaction mechanism. The correlation information for the higher-lying ${}^7\mathrm{He}$ excitations is available as backward-forward asymmetry for the ${}^6\mathrm{He}\text{−}n$ decay in the ${}^7\mathrm{He}$ frame. The asymmetry function has an expressed energy profile, which may be explained by using quite restrictive assumptions about structure of ${}^7\mathrm{He}$ excitations or/and peculiarities of the reaction mechanism. In the analysis of Golovkov et al. the observation the $s_{1/2}$ state in ${}^7\mathrm{He}$ is declared with $E_r\approx 2.0$ MeV. Our work is based on the same ${}^7\mathrm{He}$ data. However, the data analysis was improved and also the data interpretation is substantiated with the detailed PWBA reaction studies and coupled-channel calculations of the ${}^7\mathrm{He}$ continuous spectrum. The idea of the $s_{1/2}$ resonant state with $E_r\approx 2.0$ is rejected. In addition, the position of the $1/2^{-}$ state in ${}^7\mathrm{He}$ is confined to the interval $E_r=2.2\text{–}3.0$ MeV, with preferred value 2.6 MeV. There is indication on the second $3/2^{-}$ state in the data with $E_r\approx 4.5$ MeV and with the lower resonance energy limit $E_r\gtrsim 3.5$ MeV. Importance and prospects of more detailed correlation studies of ${}^7\mathrm{He}$ continuum are discussed.

Background: Proton elastic scattering at intermediate energy is widely employed as a tool for determining the matter radius of atomic nuclei. The sensitivity of the approach relies on high-resolution measurements at small scattering angles and low-momentum transfer. Under these conditions, the Glauber multiple scattering theory accurately describes the proton-nucleus elastic cross section.

Purpose: Investigate the sensitivity of the Glauber multiple scattering theory to uncertainties associated with input parameters such as the nuclear-matter density distribution and nucleon-nucleon data.

Method: A joint Bayesian inference was performed using 12 angular distributions of elastic scattering at different energies on ${}^{58}\mathrm{Ni}$, ${}^{90}\mathrm{Zr}$, and ${}^{208}\mathrm{Pb}$ targets. A Metropolis-Hastings algorithm was implemented to make an uncertainty quantification analysis for the input parameters used in the Glauber multiple scattering theory.

Results: The experimental cross sections were fitted simultaneously using a joint Bayesian inference approach. Posterior probability density distributions of 42 input parameters were obtained from the analysis. A moderate correlation between the nuclear density parameters and the nucleon-nucleon cross sections was found. This correlation impacts the extraction of the nuclear-matter radius.

Conclusions: The present analysis provided a consistent method for extracting the nuclear-matter density distribution of ${}^{58}\mathrm{Ni}$, ${}^{90}\mathrm{Zr}$, and ${}^{208}\mathrm{Pb}$ from data across different incident energies. Due to the correlation of the nucleon-nucleon cross sections with the other input parameters, a constrained Bayesian inference using free nucleon-nucleon cross section data was performed. The nuclear-matter radii obtained from the analysis are in good agreement with multiple results reported in the literature.