We present a comprehensive study of two-boson exchange (TBE) corrections in parity-violating electron-proton elastic scattering. Within a hadronic framework, we compute contributions from box (and crossed box) diagrams in which the intermediate states are described by nucleons and Δ baryons. The Δ contribution is found to be much smaller than the nucleon one at backward angles (small $\varepsilon$), but becomes dominant in the forward scattering limit ($\varepsilon \to 1$), where the nucleon contribution vanishes. The dependence of the corrections on the input hadronic form factors is small for $Q^2\lesssim 1\hspace{0.5em}{\mathrm{GeV}}^2$, but becomes significant at larger $Q^2$. We compute the nucleon and Δ TBE corrections relevant for recent and planned parity-violating experiments, with the total corrections ranging from $-1\%$ for forward angles to 1–2% at backward kinematics.

The observed preponderance of ground states with angular momentum $L=0$ in many-body quantum systems with random two-body interactions is analyzed in terms of correlation coefficients (covariances) among different eigenstates. It is shown that the geometric analysis of Chau et al. can be interpreted in terms of correlations (covariances) between energy eigenvalues, thus providing an entirely statistical explanation of the distribution of ground state angular momenta of randomly interacting quantum systems that, in principle, is valid for both fermionic and bosonic systems. The method is illustrated for the interacting boson model.

The core polarization effects for the electric quadrupole moments of the neutron-rich ${}^{31}\mathrm{Al}$, ${}^{33}\mathrm{Al}$, and ${}^{35}\mathrm{Al}$ isotopes in the vicinity of the island of inversion are investigated by means of the microscopic particle-vibration coupling model in which the Skyrme Hartee-Fock-Bogoliubov and quasiparticle random-phase approximations are used to calculate the single-quasiparticle wave functions and the excitation modes. It is found that the polarization charge for the proton $1d_{5/2}$ hole state in ${}^{33}\mathrm{Al}$ is quite sensitive to coupling to the neutrons in the $\mathit{pf}$-shell associated with the pairing correlations and that the polarization charge in ${}^{35}\mathrm{Al}$ becomes larger due to the stronger collectivity of the low-lying quadrupole vibrational mode in the neighboring ${}^{36}\mathrm{Si}$ nucleus.

Keeping in view the study of complete and incomplete fusion of heavy ions with a target, the forward recoil range distributions of several evaporation residues produced at 164 MeV ${}^{20}\mathrm{Ne}$-ion beam energy have been measured for the system ${}^{20}\mathrm{Ne}+{}^{165}\mathrm{Ho}$. The recoil catcher activation technique followed by off-line gamma spectroscopy has been employed. Measured forward recoil range distributions of these evaporation residues show evidence of several incomplete fusion channels in addition to complete fusion. The entire and partial linear momentum transfers inferred from these recoil range distributions were used to identify the evaporation residues formed by complete and incomplete fusion mechanisms. The results indicate the occurrence of incomplete fusion involving the breakup of ${}^{20}\mathrm{Ne}$ into ${}^4\mathrm{He}+{}^{16}\mathrm{O}$ and/or ${}^8\mathrm{Be}+{}^{12}\mathrm{C}$ followed by fusion of one of the fragments with target nucleus ${}^{165}\mathrm{Ho}$. Complete and incomplete fusion reaction channels have been identified in the production of various evaporation residues and an attempt has been made to separate out relative contributions of complete and incomplete fusion components from the analysis of the measured recoil range distribution data. The total contribution of complete and incomplete fusion channels has also been estimated.

The statistical multifragmentation model is modified to incorporate the Helmholtz free energies calculated in the finite temperature Thomas-Fermi approximation using Skyrme effective interactions. In this formulation, the density of the fragments at the freeze-out configuration corresponds to the equilibrium value obtained in the Thomas-Fermi approximation at the given temperature. The behavior of the nuclear caloric curve at constant volume is investigated in the micro-canonical ensemble, and a plateau is observed for excitation energies between 8 and 10 MeV per nucleon. A kink in the caloric curve is found at the onset of this gas transition, indicating the existence of a small excitation energy region with negative heat capacity. In contrast to previous statistical calculations, this phase transition takes place even when the system is constrained to fixed volume. The observed phase transition takes place at approximately constant entropy. The charge distribution and other observables also turn out to be sensitive to the treatment employed in the calculation of the free energies and the fragment volumes at finite temperature, specially at high excitation energies. The isotopic distribution is also affected by this treatment, which suggests that this prescription may help obtain information on the nuclear equation of state.

The separation of the source created in ultrarelativistic heavy ion collisions into a thermalized dense core and an outer mantle consisting of independent nucleon-nucleon collisions is discussed. Indications for such a two-component picture are found in the transverse mass spectra of kaons, protons, and antiprotons produced in Au-Au collisions at $\sqrt{s}=200$ GeV. Estimates of the sizes of the thermal and direct sources are compared with models separating the interaction zone into a core and a corona. New initial conditions corresponding to the dense core lead to a stronger azimuthal asymmetry of the fireball, and pressure gradients also increase. We find faster transverse hydrodynamic expansion and stronger elliptic flow for the dense core initial conditions.

The first results of a new three-dimensional, finite temperature Skyrme-Hartree-Fock$+$BCS study of the properties of inhomogeneous nuclear matter at densities and temperatures leading to the transition to uniform nuclear matter are presented. Calculations are carried out in a cubic box representing a unit cell of the locally periodic structure of the matter. A constraint is placed on the two independent components of the quadrupole moment of the neutron density to investigate the dependence of the total energy density of matter on the geometry of the nuclear structure in the unit cell. This approach allows self-consistent modeling of effects such as (i) neutron drip, resulting in a neutron gas external to the nuclear structure; (ii) shell effects of bound and unbound nucleons; (iii) the variety of exotic nuclear shapes that emerge, collectively termed nuclear pasta; and (iv) the dissolution of these structures into uniform nuclear matter as density and/or temperature increase. In Part I of this work the calculation of the properties of inhomogeneous nuclear matter in the core collapse of massive stars is reported. Emphasis is on exploring the effects of the numerical method on the results obtained; notably, the influence of the finite cell size on the nuclear shapes and energy-density obtained. Results for nuclear matter in $\beta$ equilibrium in cold neutrons stars are the subject of Part II. The calculation of the band structure of unbound neutrons in neutron star matter, yielding thermal conductivity, specific heat, and entrainment parameters, is outlined in Part III. Calculations are performed at baryon number densities of $n_b=0.04\text{−}0.12\hspace{0.5em}{\mathrm{fm}}^{-3}$, a proton fraction of $y_p=0.3$ and temperatures in the range 0–7.5 MeV. A wide variety of nuclear shapes are shown to emerge. It is suggested that thermodynamical properties change smoothly in the pasta regime up to the transition to uniform matter; at that transition, thermodynamic properties of the matter vary discontinuously, indicating a phase transition of first or second order. The calculations are carried out using the ${\mathrm{SkM}}^{*}$ Skyrme parametrization; a comparison with calculations using Sly4 at $n_b=0.08\hspace{0.5em}{\mathrm{fm}}^{-3}$, $T=0$ MeV is made.

The analysis of shape transitions in Nd isotopes, based on the framework of relativistic energy-density functionals and restricted to axially symmetric shapes in T. Nikšić, D. Vretenar, G. A. Lalazissis, and P. Ring [Phys. Rev. Lett. 99, 092502 (2007)], is extended to the region $Z=60,62,64$ with $N\approx 90$ and includes both $\beta$ and $\gamma$ deformations. Collective excitation spectra and transition probabilities are calculated starting from a five-dimensional Hamiltonian for quadrupole vibrational and rotational degrees of freedom, with parameters determined by constrained self-consistent relativistic mean-field calculations for triaxial shapes. The results reproduce available data and show that there is an abrupt change of structure at $N=90$ that can be approximately characterized by the X(5) analytic solution at the critical point of the first-order quantum phase transition between spherical and axially deformed shapes.

The electromagnetic transitions of the doublet bands with different triaxiality parameter $\gamma$ are discussed in the particle rotor model with $\pi h_{11/2}\otimes \nu h_{11/2}^{-1}$ configuration. It is found that $B(M1)$ staggering as well as the resulting $B(M1)/B(E2)$ and $B(M1){}_{\mathrm{in}}/B(M1){}_{\mathrm{out}}$ staggering are sensitive to the triaxiality parameter $\gamma$, and they associate strongly with the characters of nuclear chirality for ${15}^{°}⩽\gamma ⩽{30}^{°}$, i.e., the staggering is weak in the chiral vibration region while strong in the static chirality region. For partner bands with near degenerate energy spectra and similar $B(M1)$ and $B(E2)$ transitions, the strong $B(M1)$ staggering can be used as a fingerprint for the static chirality.

We report on the investigation of the population mechanism for the 454-keV level in ${}^{71}\mathrm{Cu}$. This level was identified for the first time in a recent Coulomb excitation measurement with a radioactive beam of ${}^{71}\mathrm{Cu}$. The selective nature of the Coulomb-excitation process as well as nuclear-structure considerations constrain the possible spin values for the newly observed state to $I^{\pi }=1/2^{-}$. A reexamination of the data set obtained in a $\beta$-decay study at the Leuven isotope separator on-line mass separator (LISOL) revealed that this state is also populated in the decay of ${}^{71}\mathrm{Ni}$, most probably by direct feeding from a newly identified $1/2^{-}$ $\beta$-decaying isomer having a $T_{1/2}=2.3(3)$ s. In this paper, we investigate the proposed scenario by reanalyzing the $\beta \text{−}\gamma$ and $\gamma \text{−}\gamma$ coincidences obtained in the $\beta$-decay study at LISOL.

The activation cross sections of $(d,p)$, $(d,2p)$, and $(d,p\alpha )$ reactions on ${}^{27}\mathrm{Al}$ were measured in the energy range from 4 to 20 MeV using the stacked-foils technique. Following a previous extended analysis of elastic scattering, breakup, and direct reaction of deuterons on ${}^{27}\mathrm{Al}$, for energies from 3 to 60 MeV, the preequilibrium and statistical emissions are considered in the same energy range. Finally, all deuteron-induced reactions on ${}^{27}\mathrm{Al}$ including the present data measured up to 20 MeV deuteron energy are properly described due to a simultaneous analysis of the elastic scattering and reaction data.

Cross-section and neutron-emission data from heavy-ion fusion-fission reactions are consistent with the fission of fully equilibrated systems with fission lifetime estimates obtained via a Kramers-modified statistical model that takes into account the classical collective motion of the system about the ground state, the temperature dependence of the location and height of fission transition points, and the orientation degree of freedom. If the “standard” techniques for calculating fission lifetimes are used, then the calculated excitation-energy dependence of fission lifetimes is incorrect. We see no evidence to suggest that the nuclear viscosity has a temperature dependence. The strong increase in the nuclear viscosity above a temperature of $~1.3$ MeV deduced by others is an artifact generated by an inadequate fission model.

In the first moments of a relativistic heavy ion collision explosive collective flow begins to grow before the matter has yet equilibrated. Here it is found that as long as the stress-energy tensor is traceless, the initial growth of the flow is independent of whether the matter is composed of fields or particles, equilibrated or not, or whether the stress-energy tensor is isotropic. By comparing several models, it appears that this equivalence extends for times of the order of 1 fm/$c$. This is sufficiently long to allow one to initialize the flow in hydrodynamic calculations independently of the early physics, and reduces the uncertainty involved in modeling the collision.

Hydrodynamic expansion of the hot fireball created in relativistic $\mathrm{Au}\text{−}\mathrm{Au}$ collisions at $\sqrt{s}=200$ GeV in $3+1$-dimensions is studied. We obtain a simultaneous, satisfactory description of the transverse momentum spectra, elliptic flow, and pion correlation radii for different collision centralities and different rapidities. Early initial time of the evolution is required to reproduce the interferometry data, which provide a strong indication of the early onset of collectivity. We can also constrain the shape of the initial energy density in the beam direction, with a relatively high initial energy density at the center of the fireball.

By applying the Hellmann-Feynman theorem to a charged pion gas, the quark and gluon condensates at low isospin density are determined by precise pion properties. At intermediate density around $f_{\pi }^2{m}_{\pi }$, from both the estimation for the dilute pion gas and the calculation with the Nambu-Jona-Lasinio model, the quark condensate is strongly and monotonously suppressed, while the gluon condensate is enhanced and can be larger than its vacuum value. This unusual behavior of the gluon condensate is universal for Bose condensed matter of mesons. Our results can be tested by lattice calculations at finite isospin density.

In their article “Existence of Long-Lived Isomeric States in Naturally-Occuring Neutron-Deficient Th Isotopes” [Phys. Rev. C 76, 021303 (2007)], Marinov et al. fail to demonstrate that basic mass spectrometric protocols, such as abundance sensitivity, linearity, and freedom from possible interferences, have been met. In particular, the claim that four isomeric states of Th have been discovered, using an inductively coupled plasma-sector field mass spectrometer (ICP-SFMS), with abundances from $(1\text{−}10)\times {10}^{-11}$ relative to ${}^{232}\mathrm{Th}$, cannot be accepted, given the known abundance sensitivities of other sector field mass spectrometers. Accelerator mass spectrometry is the only mass spectrometric methodology capable of measuring relative abundances of the magnitude claimed by Marinov et al.

Using a density functional approach based on a Skyrme interaction, thermodynamic properties of finite nuclei are investigated at nonzero temperture. The role of a momentum-dependent isovector term is now studied in addition to volume, symmetry, surface, and Coulomb effects. Various features associated with both mechanical and chemical instability and the liquid-gas coexistence curve are sensitive to the Skyrme interaction. The separated effects of the isoscalar term and the isovector term of momentum-dependent interaction are studied for a modified $\mathrm{SKM}(m^{*}=m)$ interaction. The frequently used Skyrme interaction SLy4 is one of the cases considered and is shown to have better features for neutron star studies due to a larger symmetry energy.

The ${}^{114}\mathrm{Cd}({}^{48}\mathrm{Ca},6n\gamma )$ reaction at 215 MeV has been investigated using the Gammasphere spectrometer to study the high-spin structure of the nucleus ${}_{68}^{156}{\mathrm{Er}}_{88}$. Many new transitions have been established along with definitive spin-parity level assignments from a high-fold angular-distribution analysis. In addition, absolute $B(M1)$ and $B(E1)$ strengths have been inferred from measured $\gamma$-ray branching ratios. Strong $B(E1)$ strength (${10}^{-3}$ W.u.) is discussed in terms of possible octupole collectivity at low spin. At high spin, this nucleus undergoes a Coriolis-induced shape transition from a prolate state of collective rotation to a noncollective, triaxial-oblate configuration. The yrast positive-parity structure ultimately terminates in an energetically favored oblate state at $I^{\pi }={42}^{+}$. Several weak high-energy $\gamma$-ray transitions have been discovered that feed this favored state. State-of-the-art cranked Nilsson-Strutinsky calculations are used to interpret the high-spin behavior of ${}^{156}\mathrm{Er}$ and comparisons are made with other $N=88$ isotones.

In the Surrogate Method, the measured decay probability of a compound nucleus formed via a direct reaction is used to extract the cross section for a reaction with a different entrance channel that proceeds through the same compound nucleus. An extension of the Surrogate Method, the Surrogate Ratio Method (SRM), uses a ratio of measured decay probabilities to infer an unknown cross section relative to a known one. To test the SRM we compare the direct-reaction-induced fission probability ratio of ${}^{234}\mathrm{U}(\alpha ,{\alpha }^{\text{'}}f)$ to ${}^{236}\mathrm{U}(\alpha ,{\alpha }^{\text{'}}f)$ with the ratio of cross sections of ${}^{233}\mathrm{U}(n,f)$ to ${}^{235}\mathrm{U}(n,f)$. These ratios were found to be in agreement over an equivalent neutron energy range of 0.4–18 MeV.