We present simulations of neutron-rich matter at subnuclear densities, like supernova matter, with the time-dependent Hartree-Fock approximation at temperatures of several MeV. The initial state consists of $\alpha$ particles randomly distributed in space that have a Maxwell-Boltzmann distribution in momentum space. Adding a neutron background initialized with Fermi distributed plane waves the calculations reflect a reasonable approximation of astrophysical matter. This matter evolves into spherical, rod-like, and slab-like shapes and mixtures thereof. The simulations employ a full Skyrme interaction in a periodic three-dimensional grid. By an improved morphological analysis based on Minkowski functionals, all eight pasta shapes can be uniquely identified by the sign of only two valuations, namely the Euler characteristic and the integral mean curvature. In addition, we propose the variance in the cell density distribution as a measure to distinguish pasta matter from uniform matter.

A complete set of analyzing powers for the $\vec{d}d\to {}^3\text{H}p$ reaction at the kinetic beam energy of 200 MeV has been measured in the full angular range in the c.m. frame. The observed signs of the tensor analyzing powers $A_{yy}$, $A_{xx}$, and $A_{xz}$ at forward and backward directions have clearly demonstrated the sensitivity to the ratio of the $D$- and $S$-wave components of the triton and deuteron, respectively. The new high-precision data are compared with the prediction of the relativistic multiple-scattering model by using standard wave functions of the three-nucleon bound state and of the deuteron.

We study weakly bound deformed nuclei based on the coordinate-space Skyrme Hartree-Fock-Bogoliubov (HFB) approach, in which a large box is employed for treating the continuum and large spatial extensions. When the limit of the core-halo deformation decoupling is approached, calculations found an exotic “egg”-like structure consisting of a spherical core plus a prolate halo in ${}^{38}$Ne, in which the near-threshold nonresonant continuum plays an essential role. Generally the halo probability and the decoupling effect in heavy nuclei can be hindered by high level densities around Fermi surfaces. However, deformed halos in medium-mass nuclei are possible as the negative-parity levels are sparse, e.g., in ${}^{110}$Ge. The deformation decoupling has also been demonstrated in pairing density distributions.

The self-consistent relativistic random-phase approximation (RPA) in the radial coordinate representation is established by using the finite-amplitude method (FAM). Taking the isoscalar giant monopole resonance in spherical nuclei as example, the feasibility of the FAM for the covariant density functionals is demonstrated, and the newly developed methods are verified by the conventional RPA calculations. In the present relativistic RPA calculations, the effects of the Dirac sea can be automatically taken into account in the coordinate-space representation. The rearrangement terms due to the density-dependent couplings can be implicitly calculated without extra computational costs in both iterative and matrix FAM schemes.

Detailed $\alpha$-decay studies of ${}^{179}$Tl${}^g$ and its daughter products ${}^{175}$Au${}^g$ and ${}^{171}$Ir${}^g$ were carried out in two complementary experiments at the mass separator ISOLDE (CERN) and velocity filter SHIP (GSI). First unambiguous determination of the $\alpha$-decay properties of ${}^{175}$Au${}^g$ was performed as follows: $E_{\alpha }$ $=$ 6433(4) keV, $T_{1/2}$ $=$ 207(7) ms, and $\alpha$-decay branching ratio 90(7)$\%$. First determination of the $\alpha$-decay branching ratios for ${}^{179}$Tl${}^g$ and ${}^{171}$Ir${}^g$ was also made: $b_{\alpha }$(${}^{179}$Tl${}^g$) $=$ 60(2)$\%$ and $b_{\alpha }$(${}^{171}$Ir${}^g$) $=$ 15(2)$\%$. The spins of the ground states in ${}^{175}$Au and ${}^{171}$Ir are established as 1/2${}^{+}$.

The similarity renormalization group (SRG) is used to soften interactions for ab initio nuclear structure calculations by decoupling low- and high-energy Hamiltonian matrix elements. The substantial contribution of both initial and SRG-induced three-nucleon forces requires their consistent evolution in a three-particle basis space before applying them to larger nuclei. While, in principle, the evolved Hamiltonians are unitarily equivalent, in practice the need for basis truncation introduces deviations, which must be monitored. Here we present benchmark no-core full configuration calculations with SRG-evolved interactions in $p$-shell nuclei over a wide range of softening. These calculations are used to assess convergence properties, extrapolation techniques, and the dependence of energies, including four-body contributions, on the SRG resolution scale.

Isotopically resolved fragments with $Z\lesssim 20$ have been studied with a high-resolution telescope in a test run for the FAZIA Collaboration. The fragments were produced by the collision of a ${}^{84}$Kr beam at 35 MeV/nucleon with a neutron-rich (${}^{124}$Sn) and a neutron-poor (${}^{112}$Sn) target. The fragments, detected close to the grazing angle, are mainly emitted from the phase-space region of the projectile. The fragment isotopic content clearly depends on the neutron richness of the target and this is direct evidence of isospin diffusion between projectile and target. The observed enhanced neutron richness of light fragments emitted from the phase-space region close to the center of mass of the system can be interpreted as an effect of isospin drift in the diluted neck region.

The $J/\Psi \left(1S\right)$ and ${\Psi }^{\prime }\left(2S\right)$ production near threshold in antiproton-nucleus reactions is calculated on the basis of the Glauber model. The model takes into account the antiproton (pre-)absorption, proton Fermi motion, and charmonium formation length. We confirm an earlier prediction that the charmonium production in $\overline{p}A$ collisions at $p_{\mathrm{lab}}=3$–10 GeV/$c$ is not influenced by formation length effects and is very well suited to determine the genuine charmonium-nucleon dissociation cross sections. The comparison is performed with the $J/\Psi$ photoproduction at high energies, where formation length effects play a very important role. However, we demonstrate that the detailed structure of the proton and neutron density profiles has to be taken into account if one wants to extract information on the $J/\Psi N$ dissociation cross section from $J/\Psi$ transparency ratios. These studies are relevant for the upcoming PANDA experiment at the Facility for Antiproton and Ion Research.

We recently introduced a fluid-dynamical model for simulating relativistic nuclear collisions in the presence of a first-order phase transition and made explorative studies of head-on lead-lead collisions. We give here a more detailed account of this novel theoretical tool and carry out more exhaustive studies of the phase-separation dynamics. Extracting the density enhancement caused by the spinodal instabilities, the associated clump size distribution, and the resulting transverse flow velocity, we examine the sensitivity of these quantities to the strength of the gradient term that promotes the phase separation, to the details of the initial density fluctuations that form the seeds for the subsequent amplification, and to the equation of state.

We present calculations of the hydrodynamics of the inner crust of neutron stars, where a superfluid neutron liquid coexists with a lattice of neutron-rich nuclei. The long-wavelength collective oscillations are combinations of phonons in the lattice and phonons in the superfluid neutrons. Velocities of collective modes are calculated from information about effective nucleon-nucleon interactions derived from Lattimer and Swesty's microscopic calculations based on a compressible liquid drop picture of the atomic nuclei and the surrounding neutrons.

Recently, the triple-$\alpha$ (3$\alpha$) process, by which three ${}^4$He nuclei are fused into a ${}^{12}$C nucleus in stars, was studied by using different methods to solve the quantum mechanical three-body problem. The results for the thermonuclear reaction rate for the process differ by several orders at low stellar temperatures of ${10}^7–{10}^8$ K. In this paper, we will present calculations of the 3$\alpha$ process by using a modified Faddeev three-body formalism in which the long-range effects of Coulomb interactions are accommodated. The reaction rate of the process is calculated via an inverse process: three-alpha (3-$\alpha$) photodisintegration of a ${}^{12}$C nucleus. The calculated reaction rate is about 10 times larger than that of the Nuclear Astrophysics Compilation of Reaction Rates at ${10}^7$ K and is notably smaller than the results of recent three-body calculations. We will discuss a possible reason for the difference.

The ground state band was recently observed in the superheavy nucleus ${}^{256}$Rf. We study the rotational properties of ${}^{256}$Rf and its neighboring even-even nuclei by using a cranked shell model (CSM) with the pairing correlations treated by a particle-number conserving (PNC) method in which the blocking effects are taken into account exactly. The kinematic and dynamic moments of inertia of the ground state bands in these nuclei are well reproduced by the theory. The spin of the lowest observed state in ${}^{256}$Rf is determined by comparing the experimental kinematic moments of inertia with the PNC-CSM calculations and agrees with previous spin assignment. The effects of the high order deformation ${\varepsilon }_6$ on the angular momentum alignments and dynamic moments of inertia in these nuclei are discussed.

Excited states in the neutron-deficient isotopes ${}^{163}$Os and ${}^{165}$Os were identified using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator. The ${}^{163}$Os and ${}^{165}$Os nuclei were populated via the ${}^{106}$Cd(${}^{60}$Ni,3$n$) and ${}^{92}$Mo(${}^{78}$Kr,2$p$3$n$) reactions at bombarding energies of 270 MeV and 357 MeV, respectively. Gamma-ray emissions from these nuclei have been established unambiguously using the recoil-decay tagging technique and a coincidence analysis has allowed level schemes to be established. These results suggest that the yrast states are based upon negative-parity configurations originating from the $\nu$$f_{7/2}$ and $\nu$$h_{9/2}$ orbitals.

Excitation functions of quasielastic scattering at backward angles were measured for the weakly bound ${}^6$Li and ${}^7$Li projectiles on a ${}^{64}$Zn target at energies around the Coulomb barrier. The corresponding barrier distributions were derived from the experimental cross sections. The experimental data were analyzed within the coupled-channel model using a double-folding potential as the bare potential. Inelastic excitations of the target, the ${}^7$Li first-excited state, and ${}^{6,7}$Li resonant state(s), corresponding to sequential breakup, were included in the calculations. The comparison between the data and coupled-channel predictions shows that the effects of channels not included in the calculations, such as direct breakup and transfers, are much larger for ${}^6$Li than for ${}^7$Li.

The effect of initial-state fluctuations on jet-energy loss in relativistic heavy-ion collisions is studied in a 2+1-dimensional ideal hydrodynamic model. Within the next-to-leading order perturbative QCD description of hard scatterings, we find that a jet loses slightly more energy in the expanding quark-gluon plasma if the latter is described by the hydrodynamic evolution with fluctuating initial conditions compared to the case with smooth initial conditions. A detailed analysis indicates that this is mainly due to the positive correlation between the fluctuation in the production probability of parton jets from initial nucleon-nucleon hard collisions and the fluctuation in the medium density along the path traversed by the jet. This effect is larger in noncentral than in central relativistic heavy ion collisions and also for jet-energy loss that has a linear than a quadratic dependence on its path length in the medium.

The low spin states of ${}^{138}$Nd have been reinvestigated via the ${}^{124}$Te(${}^{19}$F,$4n1p$) reaction at a beam energy of 103 MeV. The quasi-one-phonon $\gamma$-vibrational band based on the 1013.7 keV level has been expanded and the quasi-two-phonon $\gamma$-vibrational band built on the 1842.7 keV level has been proposed. A systematic comparison supports our assignments for multiphonon $\gamma$-vibrational bands in ${}^{138}$Nd. The characteristics of $\gamma$ softness in ${}^{138}$Nd have been discussed. Triaxial projected shell model calculations can well describe the rotational feature of the bands, but they fail to reproduce simultaneously the bandhead energies of the two $\gamma$-vibrational bands if a fixed triaxial deformation is assumed.

The decays of two long-lived low-lying isomeric states of ${}^{80}$Ga were studied at the PARRNe mass separator of the ALTO ISOL facility. Over the 75 $\gamma$ rays previously attributed to the ${}^{80}$Ga decay, the decay time of 67 individual $\beta$-delayed $\gamma$ activities were measured. This allowed the determination of the decay time of these two recently reported long-lived—actually $\beta$-decaying—states as well as to partially disentangle the two decay schemes. Thanks to the relatively high spin difference between these two ${}^{80}$Ga isomers spin assignments of the daughter ${}^{80}$Ge states could be further constrained rendering the comparison with calculations easier. From this comparison it appears that the suspected maximum of collectivity at $Z=32$ along the $N=50$ line should express itself through the coexistence of spherical and collective $\gamma$-soft structures.

A mathematical model and a computer program are developed to calculate the neutron energy spectrum, angular distribution, and integrated yield of the ${}^9$Be($d$,$n$) reaction on a thick beryllium target as an accelerator-based neutron source in the incident-deuteron-energy range from 0.5 to 20.0 MeV. The double-differential cross section computed by the talys code and the stopping power derived from the SRIM-2010 code are adopted in the program. Typical computational results are presented, and are compared with the previous experimental data to evaluate the computing model as well as the characteristics of the ${}^9$Be($d$,$n$) reaction with a thick Be target. Moreover, the developed theory and calculation methods can also provide a reasonable evaluation for calculating data of double-differential cross sections and stopping power. This model and the program can predict the above characteristics parameters of the ${}^9$Be($d$,$n$) reaction for a thick beryllium target as a neutron source in the incident-deuteron-energy range from 0.5 to 20.0 MeV.

The effect of the density dependence of the nucleonic equation of state and the hyperon-meson couplings on the star properties, including strangeness content, mass, and radius, are studied within a relativistic mean-field formalism. Information is still lacking on the nucleonic equation of state at suprasaturation densities and on the hyperon interactions in nuclear matter that will allow a clear answer to the question of whether the mass of the pulsar J1614-2230 could rule out exotic degrees of freedom from the interior of compact stars. We show that some star properties are affected in a similar way by the density dependence of the symmetry energy and the hyperon content of the star. To disentangle these two effects it is essential to have a good knowledge of the equation of state at suprasaturation densities. A linear correlation between the radius and the strangeness content of a star with a fixed mass is obtained.

A systematic study of the radiative proton capture reaction for all stable nickel isotopes is presented. The results were obtained using 2.0–6.0 MeV protons from the 11-MV tandem Van de Graaff accelerator at the University of Notre Dame. The $\gamma$ rays were detected by the NSCL-SuN detector utilizing the $\gamma$-summing technique. The results are compared to a compilation of earlier measurements and discrepancies between the previous data are resolved. The experimental results are also compared to the theoretical predictions obtained using the non-smoker and smaragd codes. Based on these comparisons an improved set of astrophysical reaction rates is proposed for the ($p,\gamma$) reactions on the stable nickel isotopes as well as for the ${}^{56}$Ni($p,\gamma$)${}^{57}$Cu reaction.