Monte Carlo simulations of neutron-rich matter of relevance to the inner neutron-star crust are performed for a system of $A=5000$ nucleons. To determine the proton fraction in the inner crust, numerical simulations are carried out for a variety of densities and proton fractions. We conclude—as others have before us using different techniques—that the proton fraction in the inner stellar crust is very small. Given that the purported nuclear pasta phase in stellar crusts develops as a consequence of the long-range Coulomb interaction among protons, we question whether pasta formation is possible in such proton-poor environments. To answer this question, we search for physical observables sensitive to the transition between spherical nuclei and exotic pasta structures. Of particular relevance is the static structure factor $S\left(k\right)$—an observable sensitive to density fluctuations. However, no dramatic behavior was observed in $S\left(k\right)$. We regard the identification of physical observables sensitive to the existence—or lack thereof—of a pasta phase in proton-poor environments as an open problem of critical importance.

It is shown that the proton formation probability, extracted from experimental data corresponding to one-proton radioactivity, is divided into two regions when plotted as a function of an universal parameter. This parameter is derived from a microscopic description of the decay process. In this way we explain the systematics of proton emission half-lives. At the same time the formation probability is shown to be a useful quantity to determine the deformation property of the mother nucleus.

The low-energy level structures for the neutron-rich Co isotopes at N = 39 and N = 41 are constructed following the beta decay of the respective even-even Fe isotopes. Spin and parity assignments of the lowest energy populated state in ${}^{66}$Co and ${}^{68}$Co are consistent with a 1${}^{+}$ spin and parity assignment and attributed to the coupling of the deformed proton configurations identified in ${}^{67}$Co and deformed neutron configurations inferred from neighboring Fe isotones. Comparisons along the N = 39 and N = 41 isotonic chains reveal a similarity in the structures of the Co and Mn isotopes.

The medium-spin structure of the ${}^{92}$Rb nucleus, populated in spontaneous fission of ${}^{248}$Cm and ${}^{252}$Cf, has been studied using the EUROGAM2 and the GAMMASPHERE Ge arrays, respectively. Two isomers have been found in ${}^{92}$Rb at 284.2 and 1958.2 keV with half-lives of $T_{1/2}=54\left(3\right)$ ns and $T_{1/2}=7\left(2\right)$ ns, respectively. A measurement of neutron-induced fission of ${}^{235}$U, at the PF1B cold-neutron beam facility of the Institut Laue Langevin, Grenoble, has been performed to confirm the assignment of the $T_{1/2}=54\left(3\right)$ ns, 284.2-keV isomeric level to the ${}^{92}$Rb nucleus. Excited levels in ${}^{92}$Rb and ${}^{94}$Rb nuclei have been calculated in a large-scale shell-model framework. Isomers observed in these two nuclei have been interpreted as proton-neutron configurations involving the high-$j$ $\nu 1h_{11/2}$ and $\pi 1g_{9/2}$ orbitals.

Background: The very neutron-rich ${}^{150}$Ce is located at the edge of the $Z=56$, $N=88$ octupole deformed island. Studying its high spin states and octupole correlations is important for systematically understanding the nuclear structural characteristics in this region. Purpose: To investigate the high spin state levels and to search for octopole correlations in ${}^{150}$Ce. Methods: The high spin states of ${}^{150}$Ce are studied by measuring the prompt $\gamma$ rays in the spontaneous fission of ${}^{252}$Cf. The data analysis uses the $\gamma$-$\gamma$-$\gamma$ coincidence methods. The $\gamma \to \gamma \left(\theta \right)$ angular correlation measurements are used to determine the spin and indirectly determine the parity of particular levels. Results: A new level scheme of ${}^{150}$Ce is established. A total of 47 new transitions and 25 new levels are identified, compared with previous results. Six collective bands have been observed, and five of them are newly established. An octupole band structure with $s=+1$ in ${}^{150}$Ce has been proposed. Systematic analysis of the $B\left(E1\right)/B\left(E2\right)$ branching ratios, the levels of the octupole bands, the energy differences between negative- and positive-parity bands, and the moments of inertia of the bands is carried out for ${}^{144,146,148,150}$Ce. This analysis gives evidence for our assignment of octupole correlations in ${}^{150}$Ce. The other characteristics of the octupole bands are discussed. Conclusions: An octupole band structure is proposed in ${}^{150}$Ce. The octupole correlations in ${}^{150}$Ce are weaker and show more instability than the neighboring lighter Ce isotopes.

Inclusive breakup $\alpha$ cross sections (${\sigma }_{\alpha }^{\mathrm{incl}}$) are measured for the ${}^6$Li + ${}^{209}$Bi reaction at bombarding energies $E_{\mathrm{lab}}=24$–50 MeV. The ${\sigma }_{\alpha }^{\mathrm{incl}}$ was observed to be a substantial fraction of the total reaction cross section over the entire energy range, and it exhausts almost whole of the reaction cross section at sub-barrier energies. An investigation on the origin of large inclusive $\alpha$ reveals that most of the $\alpha$ particles are produced by noncapture breakup (${}^6$Li$\to \alpha +d$) and incomplete fusion via $d$ capture. The combined cross sections of noncapture breakup, $d$ capture, and transfer reactions successfully explain the origin of most of the experimental ${\sigma }_{\alpha }^{\mathrm{incl}}$ over the measured energy range. A comparison of the ${\sigma }_{\alpha }^{\mathrm{incl}}$ versus reduced energies for several targets involving ${}^6$Li as projectile shows that the cross sections are independent of target. Interestingly, the difference between reaction and complete fusion cross sections “${\sigma }_{\mathrm{reac}}-{\sigma }_{\mathit{CF}}$” for several reactions also shows the same behavior.

According to the driving potential of a fissile system, we propose a phenomenological fission potential for a description of the pre-neutron-emission mass distributions of neutron-induced actinide fission. Based on the nucleus-nucleus potential with the Skyrme energy-density functional, the driving potential of the fissile system is studied considering the deformations of nuclei. The energy dependence of the potential parameters is investigated based on the experimental data for the heights of the peak and valley of the mass distributions. The pre-neutron-emission mass distributions for reactions ${}^{238}$U$(n,f)$, ${}^{237}$Np$(n,f)$, ${}^{235}$U$(n,f)$, ${}^{232}$Th$(n,f)$, and ${}^{239}$Pu$(n,f)$ can be reasonably well reproduced. Some predictions for these reactions at unmeasured incident energies are also presented.

We propose a scenario where the pattern of recently observed charge-dependent azimuthal correlations can be understood qualitatively. This is based on the cluster picture and on the assumption that the charged hadrons that flow outward from the surface of the overlapping region of colliding nuclei move primarily parallel to the reaction plane. We also point out that there is a strong electric field induced by the transient magnetic field during parton production in the initial phase of relativistic heavy-ion collisions, and we discuss its possible relevance to the scenario.

Vector mesons may be photoproduced in relativistic heavy-ion collisions when a virtual photon emitted by one nucleus scatters from the other nucleus, emerging as a vector meson. The STAR Collaboration has previously presented measurements of coherent ${\rho }^0$ photoproduction at center of mass energies of 130 GeV and 200 GeV in AuAu collisions. Here, we present a measurement of the cross section at 62.4 GeV; we find that the cross section for coherent ${\rho }^0$ photoproduction with nuclear breakup is $10.5\pm 1.5\pm 1.6$ mb at 62.4 GeV. The cross-section ratio between 200 GeV and 62.4 GeV is $4.4\pm 0.6$, less than is predicted by most theoretical models. It is, however, proportionally much larger than the previously observed $15\%\pm 55\%$ increase between 130 GeV and 200 GeV.

We apply the hydrodynamic model to the dynamics of matter created in $p$-Pb collisions at $\sqrt{s_{NN}}=4.4$ TeV and $d$-Pb collisions at $\sqrt{s_{NN}}=3.11$ TeV. The fluctuating initial conditions are calculated in the Glauber Monte Carlo model for several centrality classes. The expansion is performed event by event in $(3+1)$-dimensional viscous hydrodynamics. Noticeable elliptic and triangular flows appear in the distributions of produced particles.

We searched for the ${\Phi }^{--}\left(1860\right)$ pentaquark in the photoproduction process off the deuteron in the ${\Xi }^{-}{\pi }^{-}$-decay channel using CLAS. The invariant-mass spectrum of the ${\Xi }^{-}{\pi }^{-}$ system does not indicate any statistically significant enhancement near the reported mass $M=1.860$ GeV. The statistical analysis of the sideband-subtracted mass spectrum yields a $90\%$-confidence-level upper limit of 0.7 nb for the photoproduction cross section of ${\Phi }^{--}\left(1860\right)$ with a consecutive decay into ${\Xi }^{-}{\pi }^{-}$ in the photon-energy range $4.5GeV<E_{\gamma }<5.5GeV$.

Background: The experimental study of $g(I>2)$ factors of nuclear states can provide information about the evolution of collectivity in certain regions of the nuclear chart, and assist in obtaining a microscopic description of the nuclear wave functions. The measurements and explanations of $g(I>2)$ factors are still a challenge for experiments and theory.

Purpose: Measurement of the $g\left(2_1^{+}\right)$ and $g\left(4_1^{+}\right)$ factors, the latter for the first time, in the ${}_{44}^{96}$Ru nucleus. Comparison of the experimental results with calculations using the shell model and collective models.

Methods: The experiments made use of the transient field technique, using a Coulomb-excitation reaction in inverse kinematics. Large scale shell model calculations were performed; comparisons with previous theoretical predictions, using the tidal-wave model and the hydrodynamical model, were carried out.

Results: The values of $g\left(2_1^{+}\right)=+0.46\left(2\right)$ and $g\left(4_1^{+}\right)=+0.58\left(8\right)$ were experimentally obtained. While the $g\left(2_1^{+}\right)$ value agrees with the hydrodynamical model prediction of $g=Z/A=+0.46$, the $g\left(4_1^{+}\right)$ is in agreement with the shell model predictions. The trend of the experimental $g$ factors, as a function of nuclear spin, is not reproduced by the theoretical models discussed.

Conclusions: Measurements of $g\left(2_1^{+}\right)$ and $g\left(4_1^{+}\right)$ in ${}^{96}$Ru were performed. Further theoretical efforts are necessary to explain the trend of the $g$ factors as a function of nuclear spin for the ${}^{96}$Ru nucleus. Future measurements of $g\left(4_1^{+}\right)$ should reduce the uncertainty of the result.

The kinematic characteristics of fragments are investigated using the isospin-dependent quantum molecular dynamics model accompanied by the statistical decay model GEMINI. The temperatures of single multifragmenting sources formed in those central heavy-ion collisions are extracted by two methods based on classical kinetic approaches. Differences between the slope temperature and the quadrupole temperature are discussed. Taking into account the Fermi-Dirac nature of finite nuclear systems, we derive the quantum temperatures. The quantum slope temperatures are lower than the isotope temperatures $T_{\mathrm{HeLi}}$. The quantum quadrupole temperatures are higher than the isotope temperature.

The $p(e,e^{\prime }{\pi }^{+})n$ and $p(e,e^{\prime },K^{+})\Lambda$ (${\Sigma }^0$) reactions are important tools in the study of hadron structure. In particular, the flavor degree of freedom introduced with the addition of the strange quark helps us understand the reaction mechanism underlying strangeness production, and the transition from hadronic to partonic degrees of freedom in exclusive processes. In this study, we examine the world's data on exclusive $p(e,e^{\prime }{\pi }^{+})n$ and $p(e,e^{\prime }{K}^{+})\Lambda$ cross sections. The data were combined into a superset with one global uncertainty, and examined for $-t$ dependence of the longitudinal and transverse components of the cross section as function of $Q^2$ and the longitudinal momentum fraction, $x_B$. The data suggest that the importance of $t$-channel meson exchange decreases at higher values of $x_B$. The $Q^2$ dependence of the longitudinal to transverse cross section ratio was compared with the $Q^2$-scaling expectation for hard exclusive processes.

This article extends previous studies on the effect of tensor terms in the Skyrme energy density functional by the breaking of time-reversal invariance. We have systematically probed the impact of tensor terms on properties of superdeformed rotational bands calculated within the cranked Hartree-Fock-Bogoliubov approach for different parametrizations covering a wide range of values for the isoscalar and isovector tensor coupling constants. We analyze in detail the contribution of the tensor terms to the energies and dynamical moments of inertia and study their impact on quasiparticle spectra. Special attention is devoted to the time-odd tensor terms, the effect of variations of their coupling constants, and finite-size instabilities.

High spin states in ${}^{112}$In were investigated using the ${}^{100}$Mo(${}^{16}\text{O},p3n$) reaction at 80 MeV. The excited level has been observed up to 5.6 MeV excitation energy and spin $\sim$20$\hslash$ with the level scheme showing three dipole bands. Polarization and lifetime measurements were carried out for the dipole bands. Tilted axis cranking model calculations were performed for different quasiparticle configurations of this doubly odd nucleus. Comparison of the calculations of the model with the $B\left(M1\right)$ transition strengths of the positive- and negative-parity bands firmly established their configurations.

The knowledge of excited states in the odd-odd ${}^{150}$Pm, completely unknown until recently, is important both for understanding double $\beta$ decay of ${}^{150}$Nd and for nuclear structure studies in mass regions with a quantum phase transition. A large number of excited states have been determined for the first time in this nucleus by measuring spectra of the ${}^{152}$Sm($d$,$\alpha$) direct reaction at 25 MeV with the Munich Q3D spectrograph and by $\gamma$-ray spectroscopy with the ($p,n\gamma$) reaction at 7.1 MeV at the Bucharest tandem accelerator. Some of these levels correspond to peaks recently observed with the ${(}^3$He,$t$) reaction at 140 MeV/u.

The transition form factor of ${\pi }^0\to {\gamma }^{*}\gamma$ is studied as a function of the momentum transfer $Q^2$ within the light-front quark model (LFQM). Results are compared with the experimental data by the BABAR collaboration as well as other calculations based on the LFQM in the literature. It is shown that the predicted form factor fits well with the experimental data, particularly those at the large $Q^2$ region.

We develop an energy functional with shell-model occupations as the relevant degrees of freedom and compute nuclear masses across the nuclear chart. The functional is based on Hohenberg-Kohn theory with phenomenologically motivated terms. A global fit of the 17-parameter functional to 2049 nuclear masses yields a root-mean-square deviation of $\chi =1.31$ MeV. Nuclear radii are computed within a model that employs the resulting occupation numbers.

${}^{163,164}$Dy nuclei have been measured by use of the Oslo method on data from pick-up ${(}^3\mathrm{He},\alpha )$ and inelastic scattering ${(}^3\mathrm{He}{,}^3{\mathrm{He}}^{\prime })$ reactions, respectively. The level densities for these dysprosium isotopes together with previously measured ${}^{160–162}$Dy are extracted in the region below the neutron binding energy. Thermodynamic properties are deduced within both micro-canonical and canonical ensemble theories. A phase transition from the pair-correlated state at low energies to a less correlated or uncorrelated state is studied in both ensembles. It is investigated whether the temperature of the nucleus is constant or a varying function of excitation energy. It is found that above an excitation energy of 3 MeV the temperature of all five dysprosium nuclei have a constant value within the experimental uncertainties. The impact of a constant-temperature level density versus a Fermi gas level density is discussed with respect to the canonical heat capacity.