The coherent state model is extended so that three negative parity bands are treated on equal footing with three positive parity bands. The six rotational bands are generated by projecting out angular momenta and parities from three intrinsic orthogonal states which exhibit both quadrupole and octupole deformations. The projected states are, by construction, mutually orthogonal. In the space of projected states, a subspace of quadrupole and octupole multiboson states, an effective quadrupole and octupole boson Hamiltonian is solved. The eigenstates of the model Hamiltonian are linked by multipole transition operators for which lowest order boson expressions are considered. The calculations involve six structure coefficients and two deformation parameters. All of them are fixed by a least square fit of the known experimental energies. Applications are made to ${}^{158}\mathrm{Gd},$ ${}^{172}\mathrm{Yb},$ ${}^{218}\mathrm{Ra},$ ${}^{226}\mathrm{Ra},$ ${}^{232}\mathrm{Th},$ ${}^{238}\mathrm{U},$ and ${}^{238}\mathrm{Pu}.$ Results for excitation energies and transition probabilities are compared with the corresponding data. New signatures for octupole deformation, manifested in excited bands, are pointed out.

A stochastic approach based on three-dimensional Langevin equations was applied to a more detailed study of fission dynamics in fusion-fission reactions. The dynamical model has been developed and extended to investigate fission characteristics of light fissioning nuclei at low excitation energies. The energy dependences of an anisotropy of the fission fragment angular distribution, an evaporation residue cross section, a fission cross section, mean prescission neutron, and giant dipole $\gamma$ multiplicities have been analyzed for the ${}^{16}\mathrm{O}{+}^{208}\mathrm{Pb}$-induced fission of ${}^{224}\mathrm{Th}.$ Also, dependence of the prescission neutron multiplicity on the fragment mass asymmetry and total kinetic energy have been calculated. Analysis of the results shows that not only characteristics of the mass-energy distribution of fission fragments, but also the mass and kinetic-energy dependence of the prescission neutron multiplicity, the angular anisotropy, and fission probability can be reproduced using a modified one-body mechanism for nuclear dissipation with a reduction coefficient of the contribution from a wall formula $k_s=0.25\mathrm{}–0.5$ for compound nuclei ${}^{172}\mathrm{Yb},$ ${}^{205}\mathrm{Fr},$ ${}^{215}\mathrm{Fr},$ and ${}^{224}\mathrm{Th}.$ Decrease of the prescission neutron multiplicities with fragment mass asymmetry is due to a decrease of the fission time. The results obtained show that prescission neutrons are evaporated predominantly from the nearly spherical compound nucleus at an early stage of fission process before the saddle point is reached. From performed analysis one can conclude that coordinate-independent reduction coefficient $k_s$ is not compatible with simultaneous description of the main fission characteristics for heavy fissioning systems ${}^{256}\mathrm{Fm}$ and ${}^{252}\mathrm{Fm}.$

The two-step contribution to the spin-longitudinal and the spin-transverse cross sections of ${}^{12}\mathrm{C}{,}^{40}\mathrm{Ca}\mathrm{}(p,n)\mathrm{}$ reactions at 494 MeV and 346 MeV is calculated. We use a plane-wave approximation and evaluate the relative contributions from the one-step and the two-step processes. We found that the ratios of the two-step to the one-step processes are larger in the spin-transverse cross sections than in the spin-longitudinal ones. Combining these results with the distorted-wave impulse approximation (DWIA) results we obtained considerable two-step contributions to the spin-longitudinal and the spin-transverse cross sections. The two-step processes are important in accounting for the underestimation of the DWIA results for the spin-longitudinal and the spin-transverse cross sections.

Quasielastic excitation functions for the ${}^{35}\mathrm{Cl}{+}^{105,106,110}\mathrm{Pd}$ systems were measured at a backward angle and at near barrier energies. Experimental fusion barrier distributions were derived from these measured cross sections and compared with simplified coupled-channel calculations. Coupling of inelastic excitations up to second order were insufficient to explain the data. The inclusion of specific transfer reaction channels improved the fits to these fusion barrier distributions.

The possibility of α cluster condensation has recently been suggested for some states of ${}^{12}\mathrm{C}$ and ${}^{16}\mathrm{O}$ lying near the 3α and 4α thresholds, respectively. An α-boson model was applied to examine this issue for the system of 3α and 4α particles. With the stochastic variational method, bound state solutions were obtained for both the ground and excited states. The extent of α condensation was quantified by diagonalizing density matrices. The probabilities that the α particles occupy an S orbit were 30–40 % for some candidate states of α condensation.

The rate of the nuclear reaction ${}^3\mathrm{He}+{\overrightarrow{{\mu }^{-}}}^3\mathrm{H}+\gamma +{\nu }_{\mu }$ has been calculated using both the elementary particle model (EPM) approach and the impulse approximation (IA) approach. Using the EPM approach, the exclusive statistical radiative muon capture (RMC) rate for photon energy greater than 57 MeV is found to be $0.245\hspace{0.5em}{\mathrm{s}}^{-1}$ and the ordinary muon capture (OMC) rate is found to be $1503\hspace{0.5em}{\mathrm{s}}^{-1}.$ The IA calculation exhibits a slight dependence on the type of trinucleon wave functions used. The difference between the IA and EPM calculation is larger for RMC than for OMC. To resolve the difference between the two approaches, a more detailed investigation including meson exchange corrections will be required.

The potential barriers governing the evolution of the doubly magic nucleus ${}^{40}\mathrm{Ca}$ have been determined within a rotating liquid drop model including a proximity energy term, the two-center shell model, and the Strutinsky method. In addition to the quasispherical ground state, the macromicroscopic deformation and rotational energies generate a second highly deformed minimum where superdeformed and highly deformed states may survive. The predicted characteristics roughly agree with the recently observed data on superdeformed rotational bands in ${}^{40}\mathrm{Ca}.$

An analysis of the baryon-baryon potential from the point of view of large-$N_c$ QCD is performed. A comparison is made between the $N_c$-scaling behavior directly obtained from an analysis at the quark-gluon level to the $N_c$ scaling of the potential for a generic hadronic field theory in which it arises via meson exchanges and for which the parameters of the theory are given by their canonical large-$N_c$ scaling behavior. The purpose of this comparison is to use large-$N_c$ consistency to test the widespread view that the interaction between nuclei arises from QCD through the exchange of mesons. Although at the one- and two-meson exchange level the scaling rules for the potential derived from the hadronic theory matches the quark-gluon level prediction, at the three- and higher-meson exchange level a generic hadronic theory yields a potential which scales with $N_c$ faster than that of the quark-gluon theory.

We analyzed the experimental data on the charged pion multiplicity distribution in p-AgBr interactions at 200 GeV/c and ${\pi }^{-}-\mathrm{AgBr}$ interactions at 200 and 350 GeV/c in terms of multifractals. We calculate the values of generalized dimension $D_q$ for $q=2,$ 3, 4, and 5 with the help of the method proposed by Takagi. Also from the knowledge of $D_q,$ the multifractal specific heat is calculated for different sets of interactions. It has been observed that the value of specific heat is more or less constant over the entire range of energies. This observation supports the constant specific heat approximation model and suggests that this parameter may come out as an essential characteristic of the hadron-hadron and hadron-nucleus interactions.

Cross sections and polarization transfer observables in the ${}^{16}\mathrm{O}{(p,p}^{\prime })$ reactions at 392 MeV were measured at several angles between ${\theta }_{\mathrm{lab}}=0\mathrm{}°$ and 14°. The non-spin-flip $(\Delta S=0)$ and spin-flip $(\Delta S=1)$ strengths in transitions to several discrete states and broad resonances in ${}^{16}\mathrm{O}$ were extracted using a model-independent method. The giant resonances in the energy region of $E_x=19\mathrm{}–27\hspace{0.5em}\mathrm{MeV}$ were found to be predominantly excited by $\Delta L=1\mathrm{}$ transitions. The strength distribution of spin-dipole transitions with $\Delta S=1\mathrm{}$ and $\Delta L=1\mathrm{}$ were deduced. The obtained distribution was compared with a recent shell model calculation. Experimental results are reasonably explained by distorted-wave impulse-approximation calculations with the shell model wave functions.

We present a comprehensive analysis of the nuclear effects important in deep inelastic scattering on polarized ${}^3\mathrm{He}$ over a wide range of Bjorken x, ${10}^{-4}<~x<~\mathrm{0.8.}$ Effects relevant for the extraction of the neutron spin structure function $g_1^n$ from the ${}^3\mathrm{He}$ data are emphasized.

Effects of spin polarization on the structure of symmetric nuclear matter and pure neutron matter are investigated. We show that spin polarization induces a deformation of the Fermi spheres for nucleons with spins parallel and opposite to the polarization axes. This feature can be related to the structure of the one-pion exchange contribution to a realistic nucleon-nucleon interaction. While the anisotropies in the momentum distribution lower the energy of the system by a small amount, the associated variations of the single-particle energies with the angle between the polarization axis and the particle momentum are significant.

High-spin states in ${}^{227}\mathrm{Th}$ have been populated using the reaction ${}^{226}\mathrm{Ra}(\alpha {,3n)}^{227}\mathrm{Th}$ at a bombarding energy of 33 MeV. The high-spin rotational structures of this nucleus have been refined and extended. In addition, the linking of these structures with the low-spin states known from ${}^{231}\mathrm{U}$ $\alpha$ decay has allowed a comprehensive decay scheme of this nucleus to be assembled for the first time. Four previously known rotational bands are interpreted as Coriolis coupled $K^{\pi }{=1/2\mathrm{}}^{+}$ and $K^{\pi }{=1/2\mathrm{}}^{-}$ bands, in agreement with predictions using a reflection-asymmetric mean field approach. The determination of decoupling parameters for these bands is consistent with the ${a(K}^{\pi }{=1/2\mathrm{}}^{+})=-{a(K}^{\pi }{=1/2\mathrm{}}^{-})$ rigid octupole rotor expectation. A further rotational band is interpreted as having $K^{\pi }{=3/2\mathrm{}}^{-}.$ Measured $D_0{/Q}_0$ ratios are consistent with an interpolation of the values given for neighboring even-even nuclei, providing further evidence for the significance of strong octupole correlations in this nucleus.

We present the results of a calculation of differential cross sections and polarization observables for proton-deuteron elastic scattering, for proton laboratory energies from 2.5 to 22.7 MeV. The Paris potential parametrization of the nuclear force is used. As solution method for the charged-composite particle equations the “screening and renormalization approach” is adopted which allows one to correctly take into account the Coulomb repulsion between the two protons. Comparison is made with the precise experimental data of Sagara et al. [Phys. Rev. C 50, 576 (1994)] and of Sperison et al. [Nucl. Phys. A422, 81 (1984)].

The defining characteristics of fragment emission resulting from the noncentral collision of ${}^{114}\mathrm{Cd}$ ions with ${}^{92}\mathrm{Mo}$ target nuclei at $E/A=50\mathrm{}\hspace{0.5em}\mathrm{MeV}$ are presented. Charge correlations and average relative velocities for midvelocity fragment emission exhibit significant differences when compared to standard statistical decay. These differences associated with similar velocity dissipation are indicative of the influence of the entrance channel dynamics on the fragment production process.

The space-time dynamics and pion–Hanbury Brown–Twiss (HBT) radii in central heavy ion collisions at CERN-SPS and BNL-RHIC are investigated within a hydrodynamic simulation. The dependence of the dynamics and the HBT parameters on the equation of state (EOS) is studied with different parametrizations of a chiral SU(3) $\sigma -\omega$ model. The self-consistent collective expansion includes the effects of effective hadron masses, generated by the nonstrange and strange scalar condensates. Different chiral EOS show different types of phase transitions and even a crossover. The influence of the order of the phase transition and of the latent heat on the space-time dynamics and pion-HBT radii is studied. A small latent heat, i.e., a weak first-order chiral phase transition, or a smooth crossover lead to distinctly different HBT predictions than a strong first order phase transition. A quantitative description of the data, both at SPS energies as well as at RHIC energies, appears difficult to achieve within the ideal hydrodynamic approach using the SU(3) chiral EOS. A strong first-order quasiadiabatic chiral phase transition seems to be disfavored by the pion-HBT data from CERN-SPS and BNL-RHIC.

The $\alpha$-cluster model is used to construct the double folding cluster optical model potential of heavy ions interaction. The derived potential is employed to analyze elastic scattering data of ${}^{32}\mathrm{S}{+}^{24}\mathrm{Mg}$ at 65, 75, 86, 95, and 110 MeV laboratory energies. An energy-dependent renormalization coefficient is necessary in order to obtain successful reproductions of the data.

The formation and deexcitation of fusionlike events selected in events with a total charge equal or greater than 16 in ${}^{24}\mathrm{Mg}{+}^{12}\mathrm{C}$ system has been investigated at 25, 35, and 45 MeV/nucleon with a large multidetector array. Central single-source events are selected by use of the statistical discriminant analysis method applied to a set of 26 global variables. The fusion cross section has been extracted for the three bombarding energies and compared to other experimental data and to theoretical predictions. The total multiplicity is found to first increase to a maximum value and then decrease with increasing beam energy. It is shown that this behavior is connected to the opening of multifragmentation channels at 45 MeV/nucleon and the disappearance of channels with only light charged particles.

Investigation of intermediate-velocity particle production is performed on entrance channel mass asymmetric collisions of ${}^{58}\mathrm{Ni}+\mathrm{C}$ and ${}^{58}\mathrm{Ni}+\mathrm{Au}$ at 34.5 MeV/nucleon. Distinctions between prompt preequilibrium ejections, multiple neck ruptures, and an alternative phenomenon of delayed aligned asymmetric breakup are achieved using source reconstructed correlation observables and time-based cluster recognition in molecular dynamics simulations.