When applied to a single nucleon, nuclear energy density functionals may yield a nonvanishing internal energy thus implying that the nucleon is interacting with itself. It is shown how to avoid this unphysical feature for semilocal phenomenological functionals containing all possible bilinear combinations of local densities and currents up to second order in the derivatives. The method outlined in this Rapid Communication could be easily extended to functionals containing higher-order terms, and could serve as a guide for constraining the time-odd part of the functional.

The lifetimes of the levels above spin $23/2^{-}$ in the negative-parity yrast band of ${}^{105}\mathrm{Cd}$ have been measured using the Doppler shift attenuation method. The obtained $B(E2)$ values are small and show a decrease with an increase in spin. This establishes, for the first time, antimagnetic rotation (AMR) in an odd-$A$ nucleus. An excellent agreement between the theoretical (semiclassical model) and experimental results along with a large ${\mathcal{I}}^{(2)}/B(E2)$ ratio for the states strongly suggests that the structure of the levels beyond spin $23/2^{-}$ has the character of a twin-shears type AMR band resulting from the coupling of a pair of $g_{9/2}$ proton holes with aligned $h_{11/2}$ and $(g_{7/2}){}^2$ neutron particles, along with a small contribution from the core rotation.

The flavor asymmetry of the nucleon sea is studied in the framework of the unquenched quark model in which the effects of quark-antiquark pairs ($u\mathrm{ū}$, $d\mathrm{d̄}$, and $s\mathrm{s̄}$) are taken into account via a microscopic, QCD-inspired, quark-antiquark creation mechanism. The inclusion of the $q\mathrm{q̄}$ pairs leads to an excess of $\mathrm{d̄}$ over $\mathrm{ū}$, in agreement with the experimental data for the proton. In addition, the results for the flavor asymmetry of all ground-state octet and decuplet baryons are presented. The isospin symmetry leads to simple relations among the flavor asymmetries of octet and decuplet baryons. The flavor asymmetry of the $\Sigma {}^{+}$ hyperon is predicted to be very similar to that of the proton and much larger than that for the $\Xi {}^0$ hyperon. A comparison with other approaches shows large differences in the predictions for the flavor asymmetries of the hyperons.

The ratio $R_p$ between the electric and magnetic proton form factors has been recently measured at Jefferson Lab up to $Q^2=8.5$ GeV${}^2$. We have extended the calculation of the nucleon form factors with the hypercentral constituent quark model and compared them with the data on $R_p$ and on the $Q^2$ behavior of the ratio $Q^2{F}_2/F_1$. In both cases, the theoretical curves agree with the experimental points.

The neutron-rich nucleus ${}^{149}\mathrm{Pr}$ has been studied by means of prompt and delayed $\gamma$-ray spectroscopy using the EUROGAM2 and Gammasphere arrays of Ge detectors. New spins have been assigned to a previously reported band and it is interpreted as having a $h_{11/2}$ proton structure, from a comparison with quasiparticle-rotor model calculations. The strength of octupole correlations in odd-$Z$ nuclei of the region is discussed.

Certain double differences of binding energies can be constructed that exhibit the valence proton-neutron interaction. These double differences, known as $\delta V_{\mathit{pn}}(Z,N)$, show singularities in light $N=Z$ even-even nuclei (and $N=Z-1$ even-$Z$, odd-$N$ nuclei) due to uniquely large overlaps of the proton and neutron wave functions and the short-range residual interaction. It is suggested that a similar phenomenon appears, heavily muted, in heavy nuclei as well, when one considers valence nucleon numbers. It is proposed that it arises from the overall similarity of the sequences of orbits in different major shells, giving higher overlaps when the respective proton and neutron shells are approximately equally filled.

We propose an extrapolation method utilizing energy variance in the Monte Carlo shell model to estimate the energy eigenvalue and observables accurately. We derive a formula for the energy variance with deformed Slater determinants, which enables us to calculate the energy variance efficiently. The feasibility of the method is demonstrated for the full $\mathit{pf}$-shell calculation of ${}^{56}\mathrm{Ni}$, and the applicability of the method to a system beyond the current limit of exact diagonalization is shown for the $\mathit{pf}+g_{9/2}$-shell calculation of ${}^{64}\mathrm{Ge}$.

Experimental differential observables relating to mean square charge radii, spectroscopic, and mass observables of even-even nuclei are presented for different regions in the nuclear chart. They exhibit remarkable correlations, not heretofore recognized, that provide a new perspective on structural evolution, especially in exotic nuclei. This can also be a guide for future measurements of charge radii, spectroscopic observables, and masses, as well as for future theoretical approaches.

We present results from a numerical solution to the burning of neutron matter inside a cold neutron star into stable u,d,s quark matter. Our method solves hydrodynamical flow equations in one dimension with neutrino emission from weak equilibrating reactions, and strange quark diffusion across the burning front. We also include entropy change from heat released in forming the stable quark phase. Our numerical results suggest burning front laminar speeds of $0.002$–$0.04$ times the speed of light, much faster than previous estimates derived using only a reactive-diffusive description. Analytic solutions to hydrodynamical jump conditions with a temperature-dependent equation of state agree very well with our numerical findings for fluid velocities. The most important effect of neutrino cooling is that the conversion front stalls at lower density (below $\approx 2$ times saturation density). In a two-dimensional setting, such rapid speeds and neutrino cooling may allow for a flame wrinkle instability to develop, possibly leading to detonation.

The nuclear transition matrix elements $M^{(0\nu )}$ for the neutrinoless $\beta \beta$ decay of ${}^{94,96}\mathrm{Zr}$, ${}^{98,100}\mathrm{Mo}$, ${}^{104}\mathrm{Ru}$, ${}^{110}\mathrm{Pd}$, ${}^{128,130}\mathrm{Te}$, and ${}^{150}\mathrm{Nd}$ isotopes in the case of $0^{+}\to 0^{+}$ transition are calculated using the projected-Hartree-Fock-Bogoliubov wave functions, which are eigenvectors of four different parametrizations of a Hamiltonian with pairing plus multipolar effective two-body interaction. Employing two (three) different parametrizations of Jastrow-type short-range correlations, a set of eight (twelve) different nuclear transition matrix elements $M^{(0\nu )}$ is built for each decay, whose averages in conjunction with their standard deviations provide an estimate of the model’s uncertainties.

Measurements of the ground-state nuclear spins and magnetic and quadrupole moments of the copper isotopes from ${}^{61}\mathrm{Cu}$ up to ${}^{75}\mathrm{Cu}$ are reported. The experiments were performed at the CERN online isotope mass separator (ISOLDE) facility, using the technique of collinear laser spectroscopy. The trend in the magnetic moments between the $N=28$ and $N=50$ shell closures is reasonably reproduced by large-scale shell-model calculations starting from a ${}^{56}\mathrm{Ni}$ core. The quadrupole moments reveal a strong polarization of the underlying Ni core when the neutron shell is opened, which is, however, strongly reduced at $N=40$ due to the parity change between the $\mathit{pf}$ and $g$ orbits. No enhanced core polarization is seen beyond $N=40$. Deviations between measured and calculated moments are attributed to the softness of the ${}^{56}\mathrm{Ni}$ core and weakening of the $Z=28$ and $N=28$ shell gaps.

An enhanced model, based on the extended boson approximation, for the lowest-lying states in odd-mass nuclei is presented. Our approach is built on the quasiparticle phonon model, extending it to take into account the ground-state correlations due to the action of the Pauli principle more accurately than in the conventional theory. The derived interaction strengths between the quasiparticles and the phonons in this model depend on the quasiparticle occupation numbers explicitly coupling the odd-mass nucleus equations with those of the even-even core. Within this model we calculated the transition probabilities in several Te, Xe, and Ba isotopes with $A\approx 130$.

The Coulomb and proximity potential model for deformed nuclei (CPPMDN) is used to study the favored and unfavored $\alpha$ decay of nuclei in the range $67$ ⩽ $Z$ ⩽ $91$ from both the ground state (g.s.) and isomeric state (i.s.). The computed half-lives are in good agreement with experimental data. The standard deviation of half-life is found to be 0.44. Geiger-Nuttall (GN) plots for various parent isotopes are studied. It is found that all four types of transitions (g.s.→g.s., g.s.→i.s., i.s.→g.s., i.s.→i.s.) lie on a straight line. The isomeric state $\alpha$ decay shows a behavior similar to that of the ground state and the nuclear structure of the isomeric states imitates that of the ground states. Some predictions are done for $\alpha$ transition from both ground and isomeric states, which will be useful for future experiments.

The method based on microscopic theory of nuclear reactions has been applied for the analysis of parity-violating effects in few-body systems. Different parity-violating and parity-conserving asymmetries and their dependence on neutron energy have been estimated for the $n+{}^3\mathrm{He}\to {}^3\mathrm{H}+p$ reaction. The estimated effects are in a good agreement with available exact calculations.

A simultaneous analysis of elastic scattering, fusion, and total reaction cross sections for the weakly bound systems ${}^{6,7}\mathrm{Li}$$+$${}^{28}\mathrm{Si}$ at energies close to the Coulomb barrier is performed by optical model calculations. The nuclear polarization potential $U$ is split into volume part $U_F$, which accounts for fusion reactions and a surface part $U_{\mathit{DR}}$, responsible for direct reactions. The parameters of the Woods-Saxon potentials are determined by a ${\chi }^2$ analysis of the data. The presence of the threshold anomaly or the breakup threshold anomaly is investigated from the energy dependence of both the fusion and direct reaction parts of the polarization potential.

Background: Direct measurement of the electric dipole moment (EDM) of the neutron is in the future; measurement of a nuclear EDM may well come first. The deuteron is one nucleus for which exact model calculations are feasible. Purpose: We explore the model dependence of deuteron EDM calculations. Methods: Using a separable potential formulation of the Hamiltonian, we examine the sensitivity of the deuteron EDM to variation in the nucleon-nucleon interaction. We write the EDM as the sum of two terms, the first depending on the target wave function with plane-wave intermediate states, and the second depending on intermediate multiple scattering in the ${}^3$$P$${}_1$ channel, the latter being sensitive to the off-shell behavior of the ${}^3$$P$${}_1$ amplitude. Results: We compare the full calculation with the plane-wave approximation result, examine the tensor force contribution to the model results, and explore the effect of short-range repulsion found in realistic, contemporary potential models of the deuteron. Conclusions: Because one-pion exchange dominates the EDM calculation, separable potential model calculations will provide an adequate description of the ${}^2\mathrm{H}$ EDM until such time as a measurement better than $10\%$ is obtained.

In calculations of isoscalar magnetic moments of odd-odd $N=Z$ nuclei, it was found that, for medium- to heavy-mass nuclei, large-scale shell-model calculations yielded results that were very close to those obtained with the much simpler single-$j$ shell model. To understand this, we compare isoscalar and isovector core-polarization configuration-mixing contributions to the magnetic moments of mirror pairs in first-order perturbation theory, using a spin-dependent $\delta$ interaction. We fit the strength of the $\delta$ interaction by looking at isovector and isoscalar mirror pairs. We then use the same interaction to calculate corrections due to first-order core polarization of the magnetic moments of odd-odd nuclei.

We investigate the $\mathit{pp}\to {\mathit{ppe}}^{+}{e}^{-}$ and quasifree $\mathit{pn}\to {\mathit{pne}}^{+}{e}^{-}$ reactions within an effective Lagrangian model at a laboratory kinetic energy of $1.25$ GeV for which experimental data have recently been reported by the HADES Collaboration. The model uses a meson-exchange approximation to describe the initial nucleon-nucleon ($\mathit{NN}$) scattering. Contributions to the reaction amplitudes are included from the $\mathit{NN}$ bremsstrahlung as well as from the excitation, propagation, and radiative decay of the $\Delta (1230)$ isobar state. It is found that the HADES data on the $e^{+}{e}^{-}$ invariant mass distribution in the $\mathit{pp}\to {\mathit{ppe}}^{+}{e}^{-}$ reaction are excellently reproduced by our model where the $\Delta$ isobar term dominates the spectrum. In the case of the quasifree $\mathit{pn}\to {\mathit{pne}}^{+}{e}^{-}$ reaction, a strong sensitivity to the pion electromagnetic form factor is observed which helps to bring the calculated cross sections closer to the data in the higher dilepton mass region.

Based on the isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model and the scaling model according to nucleon effective mass, effects of elastic and inelastic $\mathit{NN}$ scattering cross sections on $\pi {}^{-}/\pi {}^{+}$ in the neutron-rich reaction of ${}^{48}\mathrm{Ca}+{}^{48}\mathrm{Ca}$ at a beam energy of $400$ MeV/nucleon are studied. It is found that cross-section effects of both $\mathit{NN}$ elastic and inelastic scatterings affect ${\Delta }_{1232}$, $\pi {}^{-}$ and $\pi {}^{+}$ production, as well as the value of $\pi {}^{-}/\pi {}^{+}$.