β-delayed neutron emission branchings (or upper limits) for neutron rich ${}^{116-120}\mathrm{Rh}$, ${}^{120-122}\mathrm{Pd}$, and ${}^{124}\mathrm{Ag}$ have been measured. These branching ratios serve as direct inputs to astrophysical rapid neutron capture process models and affect the final abundances calculated in these models. In addition, half-lives for neutron rich ${}^{114-115}\mathrm{Tc}$, ${}^{114-118}\mathrm{Ru}$, ${}^{116-121}\mathrm{Rh}$, and ${}^{119-124}\mathrm{Pd}$ near the proposed path of the r-process have also been measured. The results agree with theoretical quasiparticle random-phase approximation calculations within model uncertainties; the only exception is the delayed neutron branching in the decay of ${}^{120}\mathrm{Rh}$, which is found to be much smaller than predicted.

We adopt a self-consistent cranked Nilsson plus quasiparticle random-phase approximation by using a Hamiltonian of separable form to study the collective properties of ${}^{152}\mathrm{Dy}$ as it evolves toward the superdeformed shape. Our calculation, while confirming the octupole character of the negative-parity superdeformed bands, emphasizes the effect of the new shell structure, induced by fast rotation combined with large deformation, on the other collective modes. It shows, in particular, that superdeformation enhances strongly the collectivity of the low-lying scissors mode built on the superdeformed shape.

Lifetime measurements of yrast levels in ${}^{162}\mathrm{Yb}$ and ${}^{166}\mathrm{Hf}$ were performed using the recoil distance Doppler-shift method in coincidence mode. Excited states in ${}^{162}\mathrm{Yb}$ and ${}^{166}\mathrm{Hf}$ were populated via the reactions ${}^{116}\mathrm{Cd}$(${}^{50}\mathrm{Ti}$, 4n) and ${}^{122}\mathrm{Sn}$(${}^{48}\mathrm{Ti}$, 4n), respectively. The resulting B($E2$) values are compared with the X(5) critical point model predictions and interacting boson approximation (IBA) model calculations. The X(5) model provides a reasonable description of the yrast B(E2) values in ${}^{166}\mathrm{Hf}$, whereas the IBA fails to reproduce the transition strengths from the higher spin levels. In ${}^{162}\mathrm{Yb}$, some transitions agree with the X(5) predictions while others are more consistent with the predictions of the IBA or a deformed symmetric rotor.

By taking the particle-triaxial-rotor model with variable moment of inertia, we systematically investigate the energy spectra, deformations, and single-particle configurations of the nuclei ${}^{183,185,187}\mathrm{Tl}$. The calculated energy spectra agree quite well with experimental data. The obtained results indicate that the rotation-aligned bands observed in ${}^{183,185,187}\mathrm{Tl}$ originate from one of the $[530]{\frac{1}{2}}^{-},[532]{\frac{3}{2}}^{-},[660]{\frac{1}{2}}^{+}$ proton configurations coupled to a prolate deformed core. Furthermore, the negative parity bands built upon the ${\frac{9}{2}}^{-}$ isomeric states in ${}^{183,185,187}\mathrm{Tl}$ are formed by a proton with the $[505]{\frac{9}{2}}^{-}$ configuration coupled to a core with triaxial oblate deformation, and the positive parity band on the ${\frac{13}{2}}^{+}$ isomeric state in ${}^{187}\mathrm{Tl}$ is generated by a proton with configuration $[606]{\frac{13}{2}}^{+}$ coupled to a triaxial oblate core.

An extensive application of the Holstein-Primakoff boson expansion to both single-particle angular momentum and total angular momentum provides an algebraic solution, which gives a good approximation to the exact results for the particle-rotor model with one high-j nucleon coupled to a triaxially deformed core. Two kinds of quantum numbers classify the rotational bands characteristic of the particle-rotor model and lead the selection rules for the interband and intraband transitions. The algebraic solution is compared with the experimental data for the odd mass isotopes ${}^{163,165,167}\mathrm{Lu}$ as testing grounds.

The ${}^{151}\mathrm{Sm}$($n,\gamma )$ cross section was measured with the time-of-flight technique from 0.6 eV up to 1 MeV relative to the Au standard with an overall uncertainty of typically 6%. Neutrons were produced by spallation at the innovative n_TOF facility at CERN; the $\gamma$ rays from capture events were detected with organic ${\text{C}}_6{D}_6$ scintillators. Experimental setup and data analysis procedures are described with emphasis on the corrections for detection efficiency, background subtraction, and neutron flux determination. At low energies, resonances could be resolved up to about 1 keV, yielding a resonance integral of $3575\pm 210$ b, an average s-wave resonance spacing of $\langle D_0\rangle =1.49\pm 0.07$ eV, and a neutron strength function of $\langle S_0\rangle =(3.87\pm 0.33)\times {10}^{-4}$. Maxwellian-averaged capture cross sections are reported for thermal energies between 5 and 100 keV. These results are of relevance for nuclear structure studies, nuclear astrophysics, and nuclear technology. The new value of the Maxwellian-averaged cross section at $\mathit{kT}=30$ keV is $3.08\pm 0.15$ b, considerably larger than previous theoretical estimates, and provides better constraints for the thermodynamic conditions during the occurrence of the slow neutron capture process in low-mass stars during their asymptotic giant branch phase.

We calculate the in-medium D-meson self-energies in a hot pion gas induced by resonance interactions with pions. The appropriate resonances in the s, p, and d waves of the D-meson–pion pair are represented by low-lying scalar, vector, and tensor $D^{*}$ mesons. At temperatures around 200 MeV the D-meson mass drops by $30\mathrm{MeV}$ and the scattering width grows to $60\mathrm{MeV}$. Similar medium effects are found for the $D^{*}$-vector mesons. This opens and/or enhances the decay and/or dissociation channels of the charmonium states ${\Psi }^{\text{'}},{\chi }_c$, and $J/\Psi$ to $D\overline{D},D^{*}\overline{D},D{\overline{D}}^{*}$, and $D^{*}{\overline{D}}^{*}$ pairs in pion matter.

High energy lepton scattering has been the primary tool for mapping out the quark distributions of nucleons and nuclei. Data on the proton and deuteron have shown that there is a fundamental connection between the low and high energy regimes, referred to as quark-hadron duality. We present the results of similar studies to more carefully examine scaling, duality, and in particular the EMC effect in nuclei. We extract nuclear modifications to the structure function in the resonance region, and for the first time demonstrate that nuclear effects in the resonance region are identical to those measured in deep inelastic scattering. With the improved precision of the data at large $x$, we for the first time observe that the large-$x$ crossover point appears to occur at lower $x$ values in carbon than in iron or gold.

We generalize our previous work [Phys. Rev. C 72, 035202 (2005)] on the linear response theory of the dressed quark propagator in the presence of a constant external field to the case of a variable external field in order to make it applicable to a wider class of problems. Using the axial vector vacuum susceptibility as an illustration, we apply this general formalism to extract a new expression for the axial vector vacuum susceptibility in the quantum chromodynamical (QCD) sum rule two-point external field formula. The numerical values of the axial vector vacuum susceptibility are calculated within the framework of the rainbow-ladder approximation of the Dyson-Schwinger approach. A comparison with the results of the previous approaches is given.

We construct a new relativistic mean field model by explicitly introducing a π-meson mean field with charge number and parity projection. We call this model the charge and parity projected relativistic mean field (CPPRMF) model. We take the chiral σ model Lagrangian for the construction of finite nuclei. We apply this framework first for the ${}^4\mathrm{He}$ nucleus as a pilot case and study the role of the π-meson field on the structure of nuclei. We demonstrate that it is essential to solve the mean field equation with the variation introduced after the projection in order to take the pionic correlations into account explicitly. We study the ground-state properties of ${}^4\mathrm{He}$ by varying several parameters, such as the σ-meson mass and the ω-meson coupling constant. We are able to construct a good ground state for ${}^4\mathrm{He}$. A depression appears in the central region of the density distribution, and the second maximum and the position of the dip in the form factor of ${}^4\mathrm{He}$ are naturally obtained in the CPPRMF model.

The liquid-gas phase transition in finite nuclei is studied in a heated liquid-drop model where the nuclear drop is assumed to be in thermodynamic equilibrium with its own evaporated nucleonic vapor, conserving the total baryon number and isospin of the system. It is found that in the liquid-vapor coexistence region the pressure is not a constant on an isotherm, indicating that the transition is continuous. At constant pressure, the caloric curve shows some anomalies; namely, the systems studied exhibit negative heat capacity in a small temperature domain. The dependence of this specific feature on the mass and isospin of the nucleus, Coulomb interaction, and the chosen pressure is studied. The effects of the presence of clusters in the vapor phase on specific heat have also been explored.

Based on the isospin- and momentum-dependent hadronic transport model IBUU04, effects of the nuclear symmetry energy on the single and double ${\pi }^{-}/{\pi }^{+}$ ratios in central reactions of ${}^{132}\mathrm{Sn}+{}^{124}\mathrm{Sn}$ and ${}^{112}\mathrm{Sn}+{}^{112}\mathrm{Sn}$ at a beam energy of 400 MeV/nucleon are studied. It is found that around the Coulomb peak of the single ${\pi }^{-}/{\pi }^{+}$ ratio the double ${\pi }^{-}/{\pi }^{+}$ ratio taken from the two isotopic reactions retains about the same sensitivity to the density dependence of nuclear symmetry energy. Because the double ${\pi }^{-}/{\pi }^{+}$ ratio can significantly reduce the systematic errors, it is thus a more effective probe for the high-density behavior of the nuclear symmetry energy.

We present the directed flow ($v_1$) measured in Au+Au collisions at $\sqrt{s_{\mathit{NN}}}=62.4$ GeV in the midpseudorapidity region $\left|\eta \right|<1.3$ and in the forward pseudorapidity region $2.5<\left|\eta \right|<4.0$. The results are obtained using the three-particle cumulant method, the event plane method with mixed harmonics, and for the first time at the Relativistic Heavy Ion Collider, the standard method with the event plane reconstructed from spectator neutrons. Results from all three methods are in good agreement. Over the pseudorapidity range studied, charged particle directed flow is in the direction opposite to that of fragmentation neutrons.

Explicit equations are given for describing the space-time evolution of nonideal (viscous) relativistic fluids undergoing boost-invariant longitudinal and arbitrary transverse expansion. The equations are derived from the second-order Israel-Stewart approach which ensures causal evolution. Both azimuthally symmetric (1+1)-dimensional and nonsymmetric (2+1)-dimensional transverse expansion are discussed. The latter provides the formal basis for the hydrodynamic computation of elliptic flow in relativistic heavy ion collisions including dissipative effects.

We present an exact condition for the existence of gapless quasiparticle excitations in Nambu--Jona-Lasinio models of color superconducting quark matter with a quark-quark interaction in the scalar color-antitriplet channel. The condition can be represented by a rotated ellipse in the plane of mass and chemical potential differences for the paired quark fields.

A simple phenomenological model is discussed that simultaneously accounts for the saturation of B(E2; $0_1^{+}\to$ $2_1^{+}$) values and the newly recognized near constancy of g($2_1^{+}$) factor values in deformed nuclei. The model invokes reduced effective contributions to these observables from the valence neutrons and protons. Empirical evidence supporting this ansatz comes from recently extracted proton-neutron interaction strengths.

Five-quark $\mathit{qqqq}\overline{q}$ components in the $\Delta (1232)$ are shown to contribute significantly to $\Delta (1232)\to N\pi$ decay through quark-antiquark annihilation transitions. These involve the overlap between the qqq and the $\mathit{qqqq}\overline{q}$ components and may be triggered by the confining interaction between the quarks. With a ~10% admixture of five-quark components in the $\Delta (1232)$ the decay width can be larger by factors ~2 – 3 over that calculated in the nonrelativistic quark model with three valence quarks, depending on the details of the confining interaction. The effect of transitions between the $\mathit{qqqq}\overline{q}$ components themselves on the calculated decay width is however small. The large contribution of the quark-antiquark annihilation transitions thus may compensate the underprediction of the width of the $\Delta (1232)$ by the valence quark model, once the $\Delta (1232)$ contains $\mathit{qqqq}\overline{q}$ components with ~10% probability.

High-statistics cross sections for the reactions $\gamma +p\to K^{+}+\Lambda$ and $\gamma +p\to K^{+}+{\Sigma }^0$ have been measured using CLAS at Jefferson Lab for center-of-mass energies W between 1.6 and 2.53 GeV, and for $-0.85<\cos {\theta }_{K^{+}}^{c.m.}<+0.95$. In the $K^{+}\Lambda$ channel we confirm a resonance-like structure near $W=1.9$ GeV at backward kaon angles. The position and width of this structure change with angle, indicating that more than one resonance is likely playing a role. The $K^{+}\Lambda$ channel at forward angles and all energies is well described by a t-channel scaling characteristic of Regge exchange, whereas the same scaling applied to the $K^{+}{\Sigma }^0$ channel is less successful. Several existing theoretical models are compared to the data, but none provide a good representation of the results.

The three reactions ${}^{12}\mathrm{C}$(${}^{18}\mathrm{O}$,${}^{14}\mathrm{C}$$+\alpha$)${}^{12}\mathrm{C}$, ${}^{12}\mathrm{C}$(${}^{18}\mathrm{O}$,${}^{16}\mathrm{O}$$+\alpha$)${}^{10}\mathrm{Be}$, and ${}^{12}\mathrm{C}$(${}^{18}\mathrm{O}$,${}^{18}\mathrm{O}$$+\alpha$)${}^8\mathrm{Be}$ have been used to investigate α-decaying states in the nuclei ${}^{18}\mathrm{O}$, ${}^{20}\mathrm{Ne}$, and ${}^{22}\mathrm{Ne}$ populated through inelastic scattering, 2p, and α transfer, respectively. The measurements were performed at a beam energy of 140 MeV, and two charged particle detector telescopes were used to detect the breakup of the projectile-like particle. States in ${}^{18}\mathrm{O}$, ${}^{20}\mathrm{Ne}$, and ${}^{22}\mathrm{Ne}$ were observed in the excitation energy range from 7 to 22 MeV and angular correlation techniques were used to determine the spins of a number of these states. The data are interpreted in terms of the underlying cluster structure. In the case of the ${}^{18}\mathrm{O}$, ${}^{14}\mathrm{C}$ core + α, cluster bands, that are the analog of those in ${}^{20}\mathrm{Ne}$ have been identified.

Event-by-event multiplicity fluctuations in nucleus-nucleus collisions are studied within the hadron-string dynamics (HSD) and ultra-relativistic quantum molecular dynamics (UrQMD) transport models. The scaled variances of negative, positive, and all charged hadrons in Pb+Pb at $158A$ GeV are analyzed in comparison to the data from the NA49 Collaboration. We find a dominant role of the fluctuations in the nucleon participant number for the final hadron multiplicity fluctuations. This fact can be used to check different scenarios of nucleus-nucleus collisions by measuring the final multiplicity fluctuations as a function of collision centrality. The analysis reveals surprising effects in the recent NA49 data which indicate a rather strong mixing of the projectile and target hadron production sources even in peripheral collisions.