In this study, based on the two-potential approach (TPA), we systematically investigate the proton radioactivity half-lives of 32 spherical nuclei with $69\le Z\le 81$ from the ground and/or isomeric state. While the nuclear potential of the emitted proton-daughter nucleus is obtained by using the Dirac-Brueckner-Hartree-Fock (DBHF) through the local density approximation (LDA), it is found that the calculated half-lives can reproduce the experimental data well. In addition, we extend this model to predict the half-lives of 8 spherical proton-emitting candidates whose proton radioactivity is energetically allowed or observed but not yet quantified in NUBASE2020. For comparison, systematics of proton emission proposed by Delion et al. [Phys. Rev. Lett. 96, 072501 (2006)], the universal decay rule for reduced widths proposed by Delion et al. [Phys. Rev. C 80, 024310 (2009)], the universal decay law of proton radioactivity proposed by Qi et al. [Phys. Rev. C 85, 011303 (2012)], and the new Geiger-Nuttall law of proton radioactivity proposed by Chen et al. [Eur. Phys. J. A 55, 214 (2019)] are also used. All the predicted results are basically consistent with each other.

Despite significant theoretical efforts, the CREX-PREX dilemma remains unresolved, preventing the reliable prediction of neutron (or weak-charge) radii that, besides their intrinsic nuclear-structure interest, often serve to quantify the impact of nuclear uncertainties in searches for new physics. Coherent elastic neutrino-nucleus scattering is a clean and attractive portal to new physics, whose sensitivity may be impacted by such nuclear uncertainties. In this paper I use CREX as the basis, together with a strong calcium-argon correlation, to provide a robust baseline for the weak radius of ${}^{40}\mathrm{Ar}$: $R_{\mathrm{wk}}^{40}=3.452\pm 0.028\text{(stat)}\pm 0.022\text{(syst)}\text{fm}$. The weak radius of argon is an observable, highly relevant to ongoing and future liquid-argon campaigns, that encodes the loss of coherence at small momentum transfers.

The accurate prediction of rare isotopes produced in in-flight fission of a heavy nucleus is a key question to search for new neutron-rich isotopes in the new generation of radioactive ion beam factories. Assuming that the empirical $Q_g$ scaling discovered in the projectile fragmentation reaction is obeyed in fissile fragments, i.e., the cross section of the isotopic fragment exponentially depends on its $Q_g$ value, we studied the systematic behavior of fragments produced in the in-flight fission reactions of ${}^{238}\mathrm{U}$ measured at RIKEN and GSI. The results show that $Q_g$ of the fissile fragment adheres to the same systematic regularity. This mechanistic universality establishes the $Q_g$-scaling method as a unified framework for predicting fragment yields across the projectile fragmentation reactions and fission reactions, providing crucial guidance for experiments searching for rare nuclei near the neutron-drip line and the nuclear structural evolution. Furthermore, using $Q_g$ values derived from the AME2020 atomic mass evaluation, the systematic behavior demonstrates robustness and allows the extraction of mass excesses from newly measured cross sections of neutron-rich isotopes. The mass excesses for 13 new isotopes, that is, ${}^{89}\mathrm{Ga}, {}^{91,92}\mathrm{Ge}, {}^{93-95}\mathrm{As}, {}^{96,97}\mathrm{Se}, {}^{99-101}\mathrm{Ge}$, and ${}^{102,103}\mathrm{Kr}$, were determined via the $Q_g$ systematics, showing consistency with the well-known mass models.

Background: Nuclear reactions at intermediate beam energies are often interpreted using the eikonal model. In the analysis of complex reaction probes, where few-body reaction methods are needed, the eikonal method may be used as an efficient way for describing the fragment-target reaction process.

Purpose: In this work, we perform a systematic study to test the validity of the eikonal approximation for nucleon-nucleus reactions. We also quantify uncertainties due to the nucleon optical potential on reaction observables.

Method: We inspect the validity of the eikonal model and its semiclassical correction by comparing it to exact solutions (obtained from solving the optical-model equation with a finite-differences method) for a wide range of reactions. We also study the effect of relativistic corrections, both kinematic and dynamic, by effectively incorporating the relativistic effects at intermediate energies. The uncertainties from a Bayesian global optical potential (KDUQ) are propagated to the observables of interest.

Results: Our study includes neutron and proton reactions on ${}^{27}\mathrm{Al}$, ${}^{40}\mathrm{Ca}$, ${}^{90}\mathrm{Zr}$, and ${}^{208}\mathrm{Pb}$, for a wide range of energies $E_{\mathrm{lab}}=0\text{–}400\mathrm{MeV}$. We calculate neutron-total cross sections (elastic and reactions) as well as proton-absorption cross sections as a function of beam energy, using the eikonal model, the eikonal model with a semiclassical correction, and the exact solution. We also compute angular distributions for the methods above.

Conclusions: Our results show that for the proton-absorption cross section, the eikonal model can be used down to around $60\mathrm{MeV}$ and the semiclassical correction extends its use to $30\mathrm{MeV}$. However, the validity of the eikonal model for the neutron-total cross section only goes down to $\approx 120\mathrm{MeV}$, a range extended to $\approx 50\mathrm{MeV}$ when using the semiclassical correction. We find the semiclassical correction to the eikonal model to be less effective in describing the angular distributions. The $1\sigma$ uncertainty intervals on the observables we studied is less than 5% for most of the energies considered, but increases rapidly for higher energies, namely energies outside the range of KDUQ ($E_{\mathrm{lab}}>200\mathrm{MeV}$).

Refined calculations of the radial mismatch correction, ${\delta }_{C2}$, to superallowed $0^{+}\to 0^{+}$ nuclear $\beta$ decay are performed using the shell model with realistic Woods-Saxon radial wave functions. Two important improvements are introduced: (i) charge radii used to constrain the length parameter are evaluated within a generalized formula, where proton occupation numbers are substituted by sums of spectroscopic factors, while radial wave functions are required to match separation energies with respect to the intermediate $(A-1)$-nucleon states by adjusting parameters such as the potential depth; (ii) configuration mixing wave functions and energies for many-particle states are obtained through the diagonalization of well-established effective interactions in large configuration spaces without truncation. Furthermore, a variation of $\pm 0.1\mathrm{fm}$ in the surface diffuseness parameter is now incorporated as a source of uncertainty. The present results are generally in fairly good agreement with those from previous studies. As an exception, the ${\delta }_{C2}$ value obtained for ${}^{18}\mathrm{Ne}$ is smaller by approximately a factor of 2, principally due to the updated charge-radius treatment. A reduction is also observed in most cases with $A\ge 38$, through the deviations generally remain within the newly assigned error bars. The smaller isospin-mixing counterpart, ${\delta }_{C1}$, is strongly interaction dependent, roughly following an inverse-square law with respect to the energy separation between the lowest admixed states. Therefore, an additional procedure to ensure the accurate level spacing, as well as isobaric displacements within the isospin multiplets, appears to be indispensable. Our results for ${\delta }_{C2}$ lead to a new averaged $\overline{\mathcal{F}t}$ value of $3073.11{\left(99\right)}_{\mathrm{stat}}{\left(36\right)}_{{\delta }_R^{\prime }}{\left(173\right)}_{{\delta }_{NS}}^{\prime }\mathrm{s}$ with ${\chi }^2/\nu =0.624$. The corresponding $|V_{ud}|$ value is 0.97359(33).

The neutrinoless $\beta \beta$ ($0\nu \beta \beta$) decay nuclear matrix elements (NMEs) are calculated in the interacting boson model (IBM), which is based on the nuclear energy density functional (EDF) theory. The Hamiltonian of the IBM that gives rise to the energies and wave functions of the ground and excited states of $0\nu \beta \beta$ decay emitting isotopes and corresponding final nuclei is determined by mapping the self-consistent mean-field deformation-energy surface obtained with a given EDF onto the corresponding bosonic energy surface. The transition operators are formulated using the generalized seniority scheme, and the pair structure constants are determined by the inputs provided by the self-consistent calculations. The predicted values of the $0\nu \beta \beta$-decay NMEs with the nonrelativistic and relativistic EDFs are compared with those resulting from different many-body methods. Sensitivities of the predicted NMEs to the model parameters and assumptions are discussed.

We perform time-dependent Hartree-Fock simulations of the collision between ${}^{16}\mathrm{O}$ and a rotating ${}^{24}\mathrm{Mg}$ nucleus, whose intrinsic rotation is initialized using the cranked Hartree-Fock method. At sub-barrier incident energies, nuclear rotation significantly broadens the neutron and charge distributions of the reaction products, with a strong dependence on the initial orientation of the deformed nucleus. This enhancement of net nucleon transfer is attributed to a microscopic mechanism where rotation hinders the reverse transfer of nucleons during the separation phase. Furthermore, for specific noncentral collisions, the counteralignment of intrinsic and orbital angular momenta reduces the system's total angular momentum, thereby increasing the fusion probability. These findings highlight the critical role of nuclear rotation in modulating reaction outcomes.

Nuclear excitation by electron capture (NEEC) is an important nuclear excitation mechanism which still lacks conclusive experimental verification. This is primarily attributed to strong background $\mathrm{x}/\gamma$-ray noise and competing nuclear excitation processes which would overshadow the signals in various environments that NEEC takes place. Here, we propose an experimental approach to observe the NEEC process within a background-free environment. Through collisions with a highly compressed mono-energetic electron beam in an electron beam ion trap, nuclei may get excited to a long-lived isomeric state via the NEEC process. Subsequently, ions can be extracted and Penning-trap mass spectrometry employed to unambiguously detect the isomer. Our study focuses on the promising candidate ${}^{189}\mathrm{Os}$, demonstrating measurable detection rates of the NEEC process and discussing the feasibility of the proposed approach. This new approach for observing the NEEC process may be realized in the near future.

In this work we consider neutron particle-hole excitations across the $N=126$ shell gap and perform calculations for the $N=126$ isotones, ${}^{210}\mathrm{Po},{}^{212}\mathrm{Rn},{}^{214}\mathrm{Ra}$, and ${}^{216}\mathrm{Th}$, using the nucleon-pair approximation of the shell model with particle-hole excitations. The Hamiltonian is constructed starting from the realistic low-momentum interaction, to which simple and important modifications are further made. The calculated energy levels, magnetic moments, and $B\left(E2\right)$'s are in a good agreement with available experimental data, for both the low-lying states characterized by the neutron $N=126$ closed-core state and those by neutron particle-hole excitations, and on this basis, the $3_1^{-}$ states manifest themselves with a nature of the strong mixing between the two types of configurations. The available experimental datum of $B(E3;3_1^{-}\to 0_{\mathrm{g}.\mathrm{s}.}^{+})$ is reproduced, and the neutron particle-hole excitations are found to play a decisive role here. In addition, the experimental data for the $8_1^{+}$ states, in particular the $B(E3;{11}_1^{-}\to 8_1^{+})$'s, are well reproduced and interpreted.

High-spin states in ${}^{115}\mathrm{Sb}$ were populated using the reaction ${}^{109}\mathrm{Ag}$(${}^{12}\mathrm{C},\alpha 2\mathrm{n}$) at a beam energy of 54 MeV. A new $\mathrm{\Delta }I=1$ negative parity rotational band with several linking transitions to the existing negative-parity band has been identified. Based on the experimental results and their comparison with the relativistic mean-field and multiparticle plus rotor model calculations, a chiral character of the two bands based on the $\pi g_{9/2}^{-1}\otimes \upsilon h_{11/2}{d}_{3/2}$ configuration is proposed. This observation provides further evidence for a new chiral island in the neutron-rich $A\approx$ 120 mass region.

Measurements of beam single-spin asymmetries in semi-inclusive deep-inelastic electron scattering (SIDIS) with positively charged kaons off protons have been performed with 10.6 and 10.2 GeV incident electron beams using the CLAS12 spectrometer at Jefferson Lab. We report an analysis of the electroproduction of positively charged kaons over a large kinematic range of fractional energy, Bjorken $x$, transverse momentum, and photon virtualities $Q^2$ ranging from 1 ${\mathrm{GeV}}^2$ up to 6 ${\mathrm{GeV}}^2$. This is the first published multidimensionally binned CLAS12 measurement of a kaon SIDIS single-spin asymmetry in the valence quark regime. The data provide constraints on the structure function ratio $F_{LU}^{sin\varphi }/F_{UU}$, where $F_{LU}^{sin\varphi }$ is a quantity with a leading twist of twist-3 that can reveal novel aspects of the quark-gluon correlations within the nucleon. The impact of the data on understanding the underlying reaction mechanisms and their kinematic variation is explored using theoretical models for the different contributing twist-3 parton-distribution functions (PDFs) and fragmentation functions (FFs).

In our previous work [Phys. Rev. C 101, 014003 (2020)], we analyzed all available data on differential cross sections and spin density matrix elements for the $\gamma p\to K^{*+}\mathrm{\Lambda }$ reaction using an effective Lagrangian approach. There, the $t$-channel $K, K^{*}$, and $\kappa$ exchanges, the $u$-channel $\mathrm{\Lambda }, \mathrm{\Sigma }$, and ${\mathrm{\Sigma }}^{*}$ exchanges, the $s$-channel $N, N\left(2060\right)5/2^{-}$, and $N\left(2000\right)5/2^{+}$ exchanges, and the interaction current were taken into account in constructing the reaction amplitudes. It was found that, overall, the agreement of the theoretical results with the corresponding data is fairly good. However, noticeable discrepancies between the model results and the data on spin density matrix elements ${\rho }_{00}$ are still observed in the center-of-mass energy region around $W\approx 2.08$ GeV, indicating the need for additional reaction mechanisms. On the other hand, the hidden-strange pentaquark-like state $N\left(2080\right)3/2^{-}$, which is proposed to be a $K^{*}\mathrm{\Sigma }$ molecular state as the strange partner of the $P_c\left(4457\right)$ hadronic molecule, has been found to play quite active roles in reproducing the data for $K^{*+}{\mathrm{\Sigma }}^0, K^{*0}{\mathrm{\Sigma }}^{+}$, and $\varphi p$ photoproduction reactions. Based on these observations, in the present work, we reanalyze the data for the $\gamma p\to K^{*+}\mathrm{\Lambda }$ reaction by incorporating the pentaquark-like state $N\left(2080\right)3/2^{-}$ in our previously proposed model. The results show that, with the inclusion of the contributions of $N\left(2080\right)3/2^{-}$, the quality of the theoretical description of the $\gamma p\to K^{*+}\mathrm{\Lambda }$ data can be considerably improved. In particular, the data on spin density matrix elements ${\rho }_{00}$ and $\mathrm{Re}{\rho }_{10}$ in the near-threshold energy region are significantly better reproduced. This achievement indicates that the hypothesis of the $N\left(2080\right)3/2^{-}$ molecular state is compatible with the available data for the $\gamma p\to K^{*+}\mathrm{\Lambda }$ reaction. The reaction mechanism of $\gamma p\to K^{*+}\mathrm{\Lambda }$ is analyzed and the $N\left(2080\right)3/2^{-}, N\left(2060\right)5/2^{-}, N\left(2000\right)5/2^{+}$, and $K$ exchanges are found to provide dominant contributions.

The upper limit on the mass of the Majorana neutrino, extracted from the limits on the nonobservation of the neutrinoless double-$\beta$ ($0\nu \beta \beta$) decay, is hampered by uncertainties in the matrix elements of the transition operators. Recently, we have shown that the values of the effective axial-vector current coupling constants ($g_A^{\text{eff}}$) for the $0\nu \beta \beta$ and the two-neutrino double-$\beta$ decays are close. This striking result was obtained for the first time by including vertex corrections and two-body currents in these matrix elements. In this Letter, we calculate the half-life for the $0\nu \beta \beta$ decay ($T_{1/2}^{0\nu }$) of ${}^{136}\mathrm{Xe}$ using this closeness and show the convergence of the half-life with respect to the variation of the method to determine $g_A^{\text{eff}}$. The closeness of the $g_A^{\text{eff}}$ of the two decay modes plays a decisive role in predicting $T_{1/2}^{0\nu }$. The appropriate value of $g_A^{\text{eff}}$ depends on the assumptions made for the sectors of the nuclear structure and transition operators of the calculations within the perturbation scheme. The value $g_A^{\text{eff}}\approx 1$ is obtained when the ${\mathrm{SkM}}^{*}$ is used to describe the nuclear structure component, while a smaller value of $g_A^{\text{eff}}$ is obtained by applying a less realistic interaction like the SGII one.

Background: Muon nuclear capture is a reaction between a muon and a proton inside a nucleus through weak interactions. This reaction results in the formation of an excited nucleus, which subsequently deexcites by emitting several particles. Examination of the excited state allows for an investigation of the properties of nuclear excitation and particle emission in highly excited nuclei.

Purpose: This study investigates muon nuclear capture of ${}^{27}\mathrm{Al}$ and ${}^{28,29,30}\mathrm{Si}$, focusing on determining the absolute production branching ratio (BR) following muon nuclear capture and subsequent particle emissions. By measuring the absolute production BR, we can collect valuable information on the excitation energy distribution of muon nuclear capture.

Methods: Measurements were conducted using the in-beam activation method at two pulsed muon facilities: RIKEN-RAL beamline, ISIS Neutron and Muon Facility at Rutherford Appleton Laboratory and Materials and Life Science Experimental Facility at Japan Proton Accelerator Research Complex. Absolute BRs were determined by measuring the number of muons irradiating the target using a plastic scintillator and the $\beta$-delayed $\gamma$ rays emitted from the produced nuclei using germanium detectors.

Results: The absolute production branching ratios of muon nuclear capture on ${}^{27}\mathrm{Al}$ and ${}^{28,29,30}\mathrm{Si}$ were obtained with the highest accuracy to date. Predominant neutron emissions, even-odd atomic number dependence of particle emission probabilities, and influence of the neutron excess were observed. These results were compared with previous measurements and theoretical models and discussed regarding the excitation energy distribution, particle emission mechanism, and nuclear properties, such as resonance in the isovector transition.

Conclusion: This study emphasizes the importance of considering nuclear structure effects, even-odd effects of proton and neutron numbers, neutron excess, nucleon pairing effect, and particle emission mechanisms, in the context of the muon nuclear capture reaction.

We present a novel relativistic Green's function approach formulated in the complex momentum representation (CGF), implemented within three theoretical frameworks: the Dirac equation, the relativistic point-coupling (RMFpc) model, and the relativistic mean-field (RMF) theory. The method provides rigorous treatment of long-range Coulomb potentials through complex momentum representation while employing Landé subtraction to remove singularities. Validation via Dirac-CGF calculations of single-proton emissions in ${}^{37,39}\mathrm{Sc}$ successfully reproduces sharp resonance peaks in the $1f_{7/2}$ orbital. Calculations yield precise $Q$ values and lifetimes that show excellent agreement with both experimental data and time-dependent Dirac results. Expanding to the RMF framework, after examining the applicability of the RMF calculation and the validity of ${}^{37,39}\mathrm{Sc}$ as a magic number plus a proton model, we performed RMFpc-CGF and RMF-CGF calculations. Both clearly displayed resonant peaks in these nuclei. Notably, RMFpc-CGF calculations using PC-PK1 and RMF-CGF calculations using NL3* showed outstanding consistency with experimental $Q$ values and half-lives for ${}^{37,39}\mathrm{Sc}$, demonstrating the superior capability of these approaches for studying proton emission phenomena.

Elastic scattering between $\alpha$ particles and ${}^{12}\mathrm{C}$ nuclei plays a crucial role in understanding resonance phenomena in light nuclear systems. In this work, we construct inverse potentials for resonant states in $\alpha \text{−}{}^{12}\mathrm{C}$ elastic scattering using the variable phase approach, in tandem with a genetic-algorithm-based optimization technique. The reference function for the potential in the phase equation is chosen as a combination of three smoothly joined Morse-type functions. The parameters of the reference function are genetically evolved to minimize the the mean-squared error (MSE) between the numerically obtained scattering phase shifts and the expected values. To avoid overfitting and ensure model generalization, we employ a fivefold cross-validation strategy, where the genetic algorithm (GA) minimizes the average validation error across folds. The resulting inverse potentials accurately reproduce the resonance energies ($E_r$) and the resonance widths (${\mathrm{\Gamma }}_r$) for the ${\ell }^{\pi }$ states, $1^{-}$, $2^{+}$, $3^{-}$, and $4^{+}$, showing excellent agreement with experimental data. This computational approach to constructing inverse potentials serves as a complement to conventional direct methods for investigating nuclear-scattering phenomena.

The idea of the universal function is a fundamental advantage of the proximity potential model. In recent years, several formulas for this function have been given in the framework of the original proximity potential of 1977 (Prox 77). We present a systematic study of the role of the universal function of the proximity potential model in an $\alpha$-decay process for 250 ground-state-to-ground-state transitions using the WKB approximation. In order to realize this goal, five universal functions proposed in the proximity models gp 77, Guo 2013, Ngo 80, Zhang 2013, and Prox 2010 have been incorporated into the formalism of Prox 77. The obtained results show that the radial behavior of universal function affects the penetration probability of the $\alpha$ particle. The theoretical $\alpha$-decay half-lives are calculated and compared with the corresponding experimental data. It is determined that the Prox 77 with Guo 2013 universal function provides the best fit to the available data (with standard deviation $\sigma =0.49$). The Geiger-Nuttall plots for various isotopic groups have been investigated using this modified form of the proximity potential model. The role of the different universal functions in the $\alpha$-decay half-lives of superheavy nuclei with $Z=104\text{–}118$ are also studied. It is shown that the experimental half-lives in the superheavy mass region are described well using the Prox 77 with Zhang 2013 universal function. In this paper, the validity of the original and modified forms of the proximity 77 potential is also examined for complete fusion reactions between $\alpha$ particles and ten different target nuclei. Our results show that the measured $\alpha$-induced fusion reaction cross sections can be well reproduced using the Prox 77 with Zhang 2013 universal function for the reactions involving light and medium nuclei, whereas the Prox 77 with Guo 2013 universal function model demonstrates a reliable agreement with the experimental data at sub-barrier energies for the heaviest systems.