The differential isospin-fractionation (IsoF) during the liquid-gas phase transition in dilute asymmetric nuclear matter is studied as a function of nucleon momentum. Within a self-consistent thermal model it is shown that the neutron/proton ratio of the gas phase becomes smaller than that of the liquid phase for energetic nucleons, although the gas phase is overall more neutron-rich. Clear indications of the differential IsoF consistent with the thermal model predictions are demonstrated within a transport model for heavy-ion reactions. Future comparisons with experimental data will allow us to extract critical information about the momentum dependence of the isovector strong interaction.

The $g$ factors of the $2_1^{+},3_1^{-}$, and $4_1^{+}$ states of ${}^{70}\mathrm{Ge}$ have been measured by the transient field technique. The measured value, $g(4_1^{+})=+0.5(2)$ is in good agreement with the results of shell-model calculations within the full $\mathit{fp}$ configuration space and with the nuclear $g$-factor systematics in this region. The measured $g(4_1^{+})$ is consistent with the recently reported positive $g(4_1^{+})$ value for ${}^{68}\mathrm{Zn}$, the $N=38$ isotone of ${}^{70}\mathrm{Ge}$. The determination of the logarithmic slope of the particle-γ angular correlations is discussed for two typical arrangements of transient field experiments.

We consider the rigid-body quantization of Skyrmions with topological charges 1 to 8, as approximated by the rational map ansatz. Novel general expressions for the elements of the inertia tensors, in terms of the approximating rational map, are presented and are used to determine the kinetic energy contribution to the total energy of the ground and excited states of the quantized Skyrmions. Our results are compared to the experimentally determined energy levels of the corresponding nuclei, and the energies and spins of a few as yet unobserved states are predicted.

We present microscopic calculations of cross sections for scattering of identical and nonidentical nucleons in symmetric nuclear matter at various densities, using the Brueckner-Hartree-Fock approximation scheme with the Argonne $v_{14}$ potential including the contribution of microscopic three-body forces. We investigate separately the effects of three-body forces on the effective mass and on the scattering amplitude. In the present calculation, the rearrangement contribution of the three-body force is considered, which reduces the neutron and proton effective mass and suppresses the magnitude of the cross section. The presence of “Z diagrams” in the three-body force enables us to make a comparison with the medium effects on the nucleon-nucleon cross sections obtained with the Dirac-Brueckner-Hartree-Fock approximation.

We examine how the binding of light ($A⩽8$) nuclei depends on possible variations of hadronic masses, including meson, nucleon, and nucleon-resonance masses. Small variations in hadronic masses may have occurred over time; the present results can help evaluate the consequences for big bang nucleosynthesis. Larger variations may be relevant to current attempts to extrapolate properties of nucleon-nucleon interactions from lattice QCD calculations. Results are presented as derivatives of the energy with respect to the different masses so they can be combined with different predictions of the hadronic mass-dependence on the underlying current-quark mass $m_q$. As an example, we employ a particular set of relations obtained from a study of hadron masses and sigma terms based on Dyson-Schwinger equations and a Poincaré-covariant Faddeev equation for confined quarks and diquarks. We find that nuclear binding decreases moderately rapidly as the quark mass increases, with the deuteron becoming unbound when the pion mass is increased by $~60\%$ (corresponding to an increase in $X_q=m_q/{\Lambda }_{\mathrm{QCD}}$ of 2.5). In the other direction, the dineutron becomes bound if the pion mass is decreased by $~15\%$ (corresponding to a reduction of $X_q$ by $~30\%$). If we interpret the disagreement between big bang nucleosynthesis calculations and measurements to be the result of variation in $X_q$, we obtain an estimate $\delta X_q/X_q=K·(0.013\pm 0.002)$ where $K~1$ (the expected accuracy in $K$ is about a factor of 2). The result is dominated by ${}^7\mathrm{Li}$ data.

We study the spin-orbit splitting ($\mathit{ls}$ splitting) for the proton $d$ orbits in ${}^{23}\mathrm{F}$ in the Hartree-Fock framework with the tensor force in the exchange channel. ${}^{23}\mathrm{F}$ has one more proton around the neutron-rich nucleus ${}^{22}\mathrm{O}$. A recent experiment indicates that the $\mathit{ls}$ splitting for the proton $d$ orbits in ${}^{23}\mathrm{F}$ is reduced from that in ${}^{17}\mathrm{F}$. Our calculation shows that the $\mathit{ls}$ splitting in ${}^{23}\mathrm{F}$ becomes smaller by a few MeV because of the tensor force. This effect comes from the interaction between the valence proton and occupied neutrons in the $0d_{5/2}$ orbit through the tensor force and makes the $\mathit{ls}$ splitting in ${}^{23}\mathrm{F}$ close to the experimental data.

In conditions of $4\pi$-geometry, the production of ${\Delta }^{++}$ and ${\Delta }^0$ resonances in ${\pi }^{-}+$ ${}^{12}\mathrm{C}$ interactions at 40 GeV/$c$ was investigated for the first time. The masses and widths of resonances were obtained from an analysis of the experimental and background invariant mass distributions of $p{\pi }^{\pm }$ pairs. The fractions of charged pions coming from ${\Delta }^{++}$ and ${\Delta }^0$ decay as well as the inclusive cross-section of ${\Delta }^{++}$ and ${\Delta }^0$ production were determined. The results obtained were compared to the recent results on $\Delta (1232)$ production in ${}^4\mathrm{He}$ $+\mathrm{C}$ and $\mathrm{C}+\mathrm{C}$ collisions at 4.2 GeV/$c$ per nucleon, and $\mathrm{Ni}+\mathrm{Ni}$ and $\mathrm{Au}+\mathrm{Au}$ collisions at energies between 1 and $2A$ GeV.

We show that the charge radii of axially asymmetric nuclei calculated in the frame of the finite-range droplet model are in better agreement with measured charge radii when axial asymmetry is taken into account. This improvement is mainly the result of a new set of ground-state quadrupole deformations ${\beta }_2$, generated when masses are calculated including axial asymmetry, and to a much lesser degree due to the inclusion of the axial asymmetry in the calculation of the charge radii itself.

We reexamine the time-delay formalism of Wigner, Eisenbud, and Smith, which was developed to analyze both elastic and inelastic resonances. An error in the paper of Smith has propagated through the literature. We correct this error and show how the results of Eisenbud and Smith are related. We also comment on some recent time-delay studies, based on Smith's erroneous interpretation of the Eisenbud result.

We report a measurement of dressed spin effects of polarized ${}^3\mathrm{He}$ atoms from a cold atomic source traversing a region of a constant magnetic field $B_0$ and a transverse oscillatory dressing field $B_d\cos {\omega }_{d}t$. The observed effects are compared with a numerical simulation using the Bloch equation as well as a calculation based on the dressed atom formalism. An application of the dressed spin of ${}^3\mathrm{He}$ for a proposed neutron electric dipole moment measurement is also discussed.

High-resolution (${}^3\mathrm{He}$,$t$) measurements on the double β-decay ($\beta \beta$) nucleus ${}^{48}\mathrm{Ca}$ have been performed at RCNP (Osaka, Japan) to determine Gamow-Teller (${\mathrm{GT}}^{-}$) transitions to the nucleus ${}^{48}\mathrm{Sc}$, which represents the intermediate nucleus in the second-order perturbative description of the $\beta \beta$ decay. At a bombarding energy of $E_{{}^3\mathrm{He}}=420$ MeV an excitation energy resolution of 40 keV was achieved. The measurements were performed at two angle positions of the Grand Raiden Spectrometer (GRS): $0^{°}$ and $2.5^{°}$. The results of both settings were combined to achieve angular distributions, by which the character of single transitions could be determined. To characterize the different multipoles, theoretical angular distributions for states with $J^{\pi }=1^{+},2^{+},2^{-}$, and $3^{+}$ were calculated using the distorted-wave Born approximation (DWBA) Code DW81. The ${\mathrm{GT}}^{-}$ strength was extracted up to $E_x=7$ MeV and combined with corresponding ${\mathrm{GT}}^{+}$ strength deduced from the ${}^{48}\mathrm{Ti}$($d$,${}^2\mathrm{He}$)${}^{48}\mathrm{Sc}$ data to calculate the low-energy part of the $\beta \beta$-decay matrix element for the ${}^{48}\mathrm{Ca}$ $2\nu \beta \beta$ decay. We show that after applying trivial momentum corrections to the (${}^3\mathrm{He}$,$t$) spectrum, the two reaction probes, ($p,n$) and (${}^3\mathrm{He}$,$t$) reveal a spectral response to an impressively high degree of similarity in the region of low momentum transfer.

Properties of low-spin states in ${}^{114}\mathrm{Cd}$ have been studied with the ($n,n^{\text{'}}\gamma$) reaction. Gamma-ray angular distributions and excitation functions have been used to characterize the decays of the excited levels. Level lifetimes have been obtained with the Doppler-shift attenuation method. Sixteen new levels and many new transitions have been suggested below 3.5 MeV in excitation energy. Levels belonging to the phonon multiplets have been proposed based on their decay patterns and collectivity, and the existing intruder structure has been extended. A two-phonon $1_{\mathrm{ms}}^{+}$ state has been suggested. Excitation of the hexadecapole moment has been considered. Data have been compared with the theoretical calculations of the interacting boson model.

We study the resonance spectroscopy of ${}^7\mathrm{He}$ in the ${}^4\mathrm{He}$$+n+n+n$ cluster model, where the motion of valence neutrons is described in the cluster orbital shell model. Many-body resonances are treated on the correct boundary condition as the Gamow states in the complex scaling method. We obtain five resonances and investigate their properties from the configurations. In particular, the $1/2^{-}$ state is found in a low excitation energy of 1.1 MeV with a width of 2.2 MeV, whereas the experimental determination of the position of this state is not so clear. We also evaluate the spectroscopic factors of the ${}^6\mathrm{He}$-$n$ components in the obtained ${}^7\mathrm{He}$ resonances. The importance of the ${}^6\mathrm{He}$($2^{+}$) state is shown in several states of ${}^7\mathrm{He}$.

We present a systematic study of the sensitivity of quasielastic neutrino-nucleus cross sections at intermediate energies to the strange quark sea of the nucleon. To this end, we investigate the impact of the weak strangeness form factors on the ratio of proton-to-neutron knockout, the ratio of neutral-to-charged current cross sections, on the Paschos-Wolfenstein relation, and on the longitudinal helicity asymmetry. The influence of axial as well as vector strangeness effects is discussed. For the latter, we introduce strangeness parameters from various hadron models and from a recent fit to data from parity-violating electron scattering. In our model, the nuclear target is described in terms of a relativistic mean-field approach. The effects of final-state interactions on the outgoing nucleon are quantified within a relativistic multiple-scattering Glauber approach. Our results are illustrated with cross sections for the scattering of 1-GeV neutrinos and antineutrinos off a ${}^{12}\mathrm{C}$ target. Folding with a proposed FINeSSE (anti-)neutrino energy distribution has no qualitative influence on the overall sensitivity of the cross-section ratios to strangeness mechanisms. We show that vector strangeness effects are large and strongly $Q^2$ dependent.

A previously derived dispersive coupled-channels optical model potential for nucleon scattering on ${}^{232}\mathrm{Th}$ and ${}^{238}\mathrm{U}$ nuclei [Capote, Soukhovitskii, Quesade, and Chiba, Phys. Rev. C 72, 064610 (2005)] has been tested against experimental data on quasielastic ($p,n$) scattering to the isobaric analog states of corresponding target nuclei. The Lane potential derived from the isovector term of the dispersive coupled-channels optical model potential has been shown to approximately reproduce available experimental differential cross-section data for the quasielastic ($p,n$) reaction; therefore the approximate Lane consistency of that potential has been established.

Exclusive α-particle and proton production measurements of the system ${}^6\mathrm{Li}+{}^{28}\mathrm{Si}$ are performed at near-barrier energies. Each reaction channel is tagged via a particle-γ coincidence requirement. Ratios of direct to compound contributions are estimated via particle angular distribution measurements. Strong reaction channels for $n$ and $p$ transfer are identified and quantified and found to be described well on a qualitative basis with distorted-wave Born approximation calculations.

We reexamine neutron-proton pairing as a phenomenon that should be explainable in a microscopic theory of nuclear binding energies. Empirically, there is an increased separation energy when both neutron and proton numbers are even or if they are both odd. The enhancement is present at some level in nearly all nuclei: the separation energy difference has the opposite sign in less than 1% of the cases in which sufficient data exist. We discuss the possible origin of the effect in the context of density functional theory (DFT) and its extensions. Neutron-proton pairing from mean-field theory does not seem promising to explain the effect. Gao and Chen have argued that a significant part of the increased binding in odd-odd deformed nuclei might arise as a recoupling energy, and we find a similar result for spherical nuclei. This suggests that the DFT should be extended by angular momentum projection to reach an accuracy capable of treating this effect.

Cross sections for ($n,2n$), ($n,p$), ($n,\alpha$), and ($n,d^{*}$)${}^1$ reactions have been measured on ruthenium isotopes at the neutron energies of 13.5 to 14.8 MeV using the activation technique in combination with high-resolution gamma-ray spectroscopy. Data are reported for the following reactions: ${}^{104}\mathrm{Ru}$($n,2n$)${}^{103}\mathrm{Ru}$, ${}^{98}\mathrm{Ru}$($n,2n$)${}^{97}\mathrm{Ru}$, ${}^{96}\mathrm{Ru}$($n,2n$)${}^{95}\mathrm{Ru}$, ${}^{96}\mathrm{Ru}$($n,p$)${}^{96}\mathrm{Tc}$${}^g$, ${}^{96}\mathrm{Ru}$($n,p$)${}^{96}\mathrm{Tc}$${}^m$, ${}^{104}\mathrm{Ru}$($n,p$)${}^{104}\mathrm{Tc}$, ${}^{102}\mathrm{Ru}$($n,p$)${}^{102}\mathrm{Tc}$${}^m$, ${}^{104}\mathrm{Ru}$$(n,\alpha$)${}^{101}\mathrm{Mo}$, ${}^{102}\mathrm{Ru}$$(n,\alpha$)${}^{99}\mathrm{Mo}$, ${}^{96}\mathrm{Ru}$$(n,\alpha$)${}^{93}\mathrm{Mo}$${}^m$, and ${}^{96}\mathrm{Ru}$($n,d^{*}$)${}^{95}\mathrm{Tc}$${}^m$. Results were discussed and compared with the previous works.

The primary $E1\gamma$-ray transition strength from the thermal neutron capture of ${}^{18}\mathrm{O}$ to the $3/2^{-}$ state, 18 keV below the neutron threshold of ${}^{19}\mathrm{O}$, was found to be about $2\times {10}^5$ stronger than that to the $1/2^{-}$ excited state, 729 keV below the threshold. In addition, the $E1$ strength from the $3/2^{-}$ state leading to the $3/2^{+}$ state with three ($d_{5/2}){}^3$ neutrons was more than six times stronger compared to that to the $5/2^{+}$ ground state with a single ($d_{5/2}$) neutron. These anomalous γ-ray decay patterns give the first clear experimental evidence for the predicted property of the $3/2^{-}$ state as mainly having a one-hole-four-particle configuration. Unique features of the ${}^{18}\mathrm{O}$ ground state with a two-hole-four-particle configuration and of the $3/2^{+}$ state combined with a discrete prompt γ-ray spectroscopy following the thermal neutron capture of ${}^{18}\mathrm{O}$ enabled us to exclusively identify the configuration of the $3/2^{-}$ state.