Resonance structures of excited states in ${}^9\mathrm{Be}$ and ${}^9\mathrm{B}$ are studied by means of a microscopic multicluster model. The two-body scattering of ${\{}^8\mathrm{Be}{(0\mathrm{}}^{+}{,2\mathrm{}}^{+}{,4\mathrm{}}^{+})+N;$ ${}^5\mathrm{He}$ or ${}^5\mathrm{Li}{(3/2\mathrm{}}^{-}{,1/2\mathrm{}}^{-})+\alpha \}$ is solved by the microscopic R-matrix method where two-cluster wave functions of ${}^8\mathrm{Be}$ and ${}^5\mathrm{He}$ are employed. These results are compared with the $\alpha +\alpha +N$ three-body complex scaling method to check the validity of neglecting three-body channels in the microscopic R-matrix method. The ${1/2}^{+}$ first excited state of ${}^9\mathrm{Be},$ which cannot be identified in the complex scaling method, is given as a ${}^8\mathrm{Be}{(0\mathrm{}}^{+})+n$ virtual state with a purely imaginary complex momentum, and this resonance lies on the second Riemann sheet only for the ${}^8\mathrm{Be}{(0\mathrm{}}^{+})+n$ channel. The ${1/2}^{+}$ resonance of the mirror nucleus ${}^9\mathrm{B}$ has a very large width, and its excitation energy as obtained from the analytic continuation of the S matrix to the complex energies shows a normal Thomas-Ehrman shift. The dimensionless reduced widths and the reduced width amplitudes are calculated for low-lying resonances, and the cluster structure of these states in ${}^9\mathrm{Be}$ is discussed.

A microscopic formalism is developed that includes the coupling to two particle-hole phonons in the particle-hole propagator by extending the dressed random phase approximation (DRPA) equation for a finite system. The resulting formalism is applied to study the low-lying excitation spectrum of ${}^{16}\mathrm{O}.$ It is observed that the coupling to two-phonon states at low energy generates excited states with quantum numbers that cannot be obtained in the DRPA approach. Nevertheless, the two-phonon states mix weakly with particle-hole configurations and participate only partially in the formation of the lowest-lying positive-parity excited states. The stability of the present calculation is tested vs the truncation of model space. It is demonstrated that when single-particle strength fragmentation is properly considered, the present formalism exhibits convergence with respect to the chosen model space within the confines of the chosen approximation scheme.

We propose an extended Lipkin model that can describe decay processes of particle-hole states and is still solvable. We examine several RPA-type theories using the model. We show explicitly the roles played by the self-energies of particle-hole propagators, and clarify how the extended RPA theory describes collective states better than other RPA-type theories.

The ratios of inclusive electron scattering cross sections of ${}^4\mathrm{He},$ ${}^{12}\mathrm{C},$ and ${}^{56}\mathrm{Fe}$ to ${}^3\mathrm{He}$ have been measured for the first time. It is shown that these ratios are independent of $x_B$ at $Q^2>1.4\mathrm{}{\mathrm{GeV}}^2$ for $x_B>1.5,$ where the inclusive cross section depends primarily on the high momentum components of the nuclear wave function. The observed scaling shows that the momentum distributions at high-momenta have the same shape for all nuclei and differ only by a scale factor. The observed onset of the scaling at $Q^2>1.4\mathrm{}{\mathrm{GeV}}^2$ and $x_B>1.5\mathrm{}$ is consistent with the kinematical expectation that two-nucleon short range correlations (SRC) dominate the nuclear wave function at $p_m\gtrsim 300\mathrm{MeV}/c.\mathrm{}$ The values of these ratios in the scaling region can be related to the relative probabilities of SRC in nuclei with $A>~3.$ Our data, combined with calculations and other measurements of the ${}^3\mathrm{H}\mathrm{e}/\mathrm{d}\mathrm{e}\mathrm{u}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{i}\mathrm{u}\mathrm{m}$ ratio, demonstrate that for nuclei with $A>~12$ these probabilities are 4.9–5.9 times larger than in deuterium, while for ${}^4\mathrm{He}$ it is larger by a factor of about 3.8.

A nuclear vibron model for nuclear molecules consisting of two clusters with inner structure is investigated. The Hamiltonian model has a $U_{C_1}\mathrm{}\left(6\right)\mathrm{}\otimes U_{C_2}\mathrm{}\left(6\right)\mathrm{}\otimes U_R\mathrm{}\left(4\right)\mathrm{}\supset {\mathrm{SU}}_{C_1}\mathrm{}\left(3\right)\mathrm{}\otimes {\mathrm{SU}}_{C_2}\mathrm{}\left(3\right)\mathrm{}\otimes {\mathrm{SU}}_R\mathrm{}\left(3\right)\mathrm{}$ dynamical symmetry. Applying a geometrical mapping, the relation of the parameter of the coherent state to the relative distance of the two clusters is deduced. The Hamiltonian model exhibits a minimum at relative distances different from zero. It is discussed how to deduce the potential, knowing the spectrum, and how to deduce the spectrum, knowing the potential. As a classical example the system ${}^{12}\mathrm{C}{+}^{12}\mathrm{C}$ is taken, where the spectrum is known and the internuclear potential can be obtained. This system serves as a consistency check of the method. Afterwards, the heavy system ${}^{96}\mathrm{Sr}{+}^{146}\mathrm{Ba},$ playing a role as a subsystem of a possible three cluster molecule, is investigated and the possible structure of the spectrum is deduced. We show that in order to obtain a Hamiltonian consistent with a geometrical picture, the structure of this Hamiltonian is restricted. Ambiguities of the structure of the spectrum still exist but can be ordered into different classes.

Fusion barriers have been determined for light nucleus reactions leading to the synthesis of ${}^{44}\mathrm{Ti}$ and ${}^{48}\mathrm{Cr}.$ Different deformation paths from target and projectile initial ellipsoidal shapes to the final synthesized nucleus are taken into account. The microscopic effects are obtained with a deformed two-center shell model and the Strutinsky method. The macroscopic energy is calculated within a generalized liquid drop model. The results show the possibility of isomeric state formation within energy minima corresponding to a certain stage of partially overlapping target and projectile nuclei, in an angular momentum and excitation energy range depending on the asymmetry of the reaction and the shell structure of the nucleus partners.

$\alpha$-Particle singles and doubles yields for the reaction of ${}^9\mathrm{Be}{+}^{208}\mathrm{Pb}$ have been measured from below to well above the fusion barrier energy. These yields have been reproduced by calculations including both neutron transfer and inelastic excitation. The calculations predict breakup cross sections to persist to very low energies, where the latter process dominates.

The breakup of halo nuclei is studied by numerically solving the semiclassical time-dependent Schrödinger equation on an angular Lagrange mesh and on a quasiuniform radial mesh. The merits of different mesh choices and approximations of the time evolution operator are discussed. The numerical technique is applied to the breakup of the ${}^{11}\mathrm{Be}$ and ${}^{15}\mathrm{C}$ halo nuclei at energies around 70 MeV/nucleon. The time evolution of the projectile wave packet during the breakup process is visualized. The role of the nuclear interaction between target and projectile is analyzed and the validity of pure Coulomb breakup with an impact parameter cutoff is estimated. The breakup and inelastic cross sections are discussed and compared with available experimental data.

Volume integrals of the real potentials derived from elastic scattering studies of deuterons, tritons, ${}^3\mathrm{He},$ and $\alpha$ particles have been calculated for data available from the lowest to the highest energy. These volume integrals have been plotted as a function of energy per nucleon for each projectile. By selecting energy regions where there were least ambiguities in the potentials and averaging the volume integrals in 1 MeV bins, the energy dependences were determined. The volume integrals show a logarithmic dependence on the energy per nucleon. The zero crossing of the potentials is at about the same value of $\sim 650\mathrm{MeV}/$nucleon for all projectiles. With increasing projectile mass, the potentials become weaker, possibly due to Pauli blocking effects in the projectile. Neutron-rich projectiles have smaller volume integrals due to the manifestation of the isospin effect. A similar analysis of the imaginary volume integrals shows that they increase from zero at the lowest energies to about $100–150{\mathrm{MeV}\mathrm{}\mathrm{fm}}^3$ around $10\mathrm{MeV}/$nucleon and then remain essentially constant.

We present numerical results for the dissociation cross sections of ground state, and orbitally and radially excited charmonia in collisions with light mesons. Our results are derived using the nonrelativistic quark model, so all parameters are determined by fits to the experimental meson spectrum. Examples of dissociation into both exclusive and inclusive final states are considered. The dissociation cross sections of several $C=(+)\mathrm{}$ charmonia may be of considerable importance for the study of heavy ion collisions, since these states are expected to be produced more copiously than $J/\psi .$ The relative importance of the productions of ground-state and orbitally excited charmed mesons in a pion-charmonium collision is demonstrated through the $\sqrt{s}$-dependent charmonium dissociation cross sections.

Quenched lattice-QCD data on the dressed-quark Schwinger function can be correlated with dressed-gluon data via a rainbow gap equation so long as that equation’s kernel possesses enhancement at infrared momenta above that exhibited by the gluon alone. The required enhancement can be ascribed to a dressing of the quark-gluon vertex. The solutions of the rainbow gap equation exhibit dynamical chiral symmetry breaking and are consistent with confinement. The gap equation and related, symmetry-preserving ladder Bethe-Salpeter equation yield estimates for chiral and physical pion observables that suggest these quantities are materially underestimated in the quenched theory; $|〈\overline{q}q〉|$ by a factor of 2 and $f_{\pi }$ by $30\%.$

We have measured the ${}^{95}\mathrm{Mo}(n,\alpha )$ cross section in the energy range from 1 eV to 500 keV at the Oak Ridge Electron Linear Accelerator (ORELA). This work is part of a series of $(n,\alpha )$ measurements for deriving a reliable global $\alpha +\mathrm{nucleus}$ potential, which is an essential ingredient in nuclear statistical model calculations of the reaction rates for unstable nuclei involved in explosive p-process nucleosynthesis. The ${}^{95}\mathrm{Mo}(n,\alpha )$ rate shows a strong sensitivity to the $\alpha +\mathrm{nucleus}$ potential used in the calculations, and therefore these new data should be very useful in obtaining an improved potential. For example, although there is a factor of 5 variation in the rate calculated using different potentials, an older model and a newer one using one of three recently proposed potentials are in good agreement with our new data.

The kaon polarization operator in dense baryonic matter of arbitrary isotopic composition is calculated including s- and p-wave kaon-baryon interactions. The regular part of the polarization operator is extracted from the realistic kaon-nucleon interaction based on the chiral and ${1/N}_c$ expansion. Contributions of $\Lambda \mathrm{}\left(1116\right),$ $\Sigma \mathrm{}\left(1195\right),$ ${\Sigma }^{*}\mathrm{}\left(1385\right)\mathrm{}$ resonances are taken explicitly into account in the pole and regular terms with the inclusion of mean-field potentials. The baryon-baryon correlations are incorporated and fluctuation contributions are estimated. Results are applied for $K^{-}$ in neutron star matter. Within our model a second-order phase transition to the s-wave $K^{-}$ condensate state occurs at ${\rho }_c\gtrsim 4{\rho }_0$ with baryon-baryon correlations included. We show that a second-order phase transition to the p-wave $K^{-}$ condensate state may occur at densities ${\rho }_c\sim (3\mathrm{}–5){\rho }_0$ dependent on the parameter choice. We demonstrate that a first-order phase transition to a proton-enriched (approximately isospin-symmetric) nucleon matter with a p-wave $K^{-}$ condensate can occur at smaller densities, $\rho \lesssim 2{\rho }_0.$ The transition is accompanied by the suppression of hyperon concentrations.

Analysis of the ${}^9\mathrm{Be}{(}^9\mathrm{Be}{,}^8\mathrm{Be}{)}^{10}\mathrm{Be}$ reaction at $E_{\mathrm{beam}}=48\mathrm{}\mathrm{MeV}$ indicates that excited states in ${}^{10}\mathrm{Be}$ were populated up to $\sim 15\mathrm{MeV}.$ Detecting coincident $\alpha$ particles allowed the excitation energy spectrum of ${}^8\mathrm{Be}$ to be reconstructed. By gating on either the ${}^8\mathrm{Be}{2}^{+}$ or $4^{+}$ states, information on the total magnitudes of the spins of the various states in the coincident ${}^{10}\mathrm{Be}$ nuclei was obtained. Members of the ground state ${K=0\mathrm{}}^{+}$ and ${K=1\mathrm{}}^{-}$ rotational bands were populated, with the excitation energies in good agreement with the previous work. In addition, a new state was identified at 13.78 MeV.

Analyzing powers for ${\pi }^{-}p$ elastic scattering have been measured at TRIUMF using the CHAOS spectrometer and a spin-polarized target. These data were collected at a bombarding energy of $T_{\pi }=279\mathrm{}\mathrm{MeV}$ and cover an angular range of $53<~{\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}^{\pi }<~180°.$ There is good agreement between these data and the latest partial wave analysis from the VPI/GWU group.

The relativistic approach to electroweak properties of two-particle composite systems developed in A.F. Krutov and V.E. Troitsky, Phys. Rev. C 65, 045501 (2002) is generalized here to the case of nonzero spin. In developed technique the parametrization of matrix elements of electroweak current operators in terms of form factors is a realization of the Wigner-Eckart theorem on the Poincaré group and form factors are reduced matrix elements. The $\rho$-meson charge form factor is calculated as an example.

The enhancement of $\mathrm{sd}$ dominance in interacting boson models for nuclei is shown to be due primarily to the relatively small single-particle energy gap between the s boson and the d boson compared to larger single-particle energy gaps between the s and d bosons and bosons with $l>~4$ when a repulsive pairing interaction between the boson pairs is introduced.

We present model calculations of the quasiparticle random phase approximation (QRPA) with a new form of the phonon operator. This modification of the QRPA is applied to the proton-neutron Lipkin model and we shall review it briefly. The present calculations show that the inclusion of nonlinear terms in the phonon operator leads to a much better agreement with the exact results obtained by the diagonalization of the nuclear Hamiltonian. It is further found that if all relevant nonlinear terms of the phonon operator are taken into account, all odd excited states are also exactly reproduced.