The self-consistent cranking method is tested by comparing the cranking calculations in the interacting boson model with the exact results obtained from the SU(3) and O(6) dynamical symmetries and from numerical diagonalization. The method is used to study the spin dependence of shape variables in the $\mathrm{sd}$ and $\mathrm{sdg}$ boson models. When realistic sets of parameters are used, both models lead to similar results: axial shape is retained with increasing cranking frequency while fluctuations in the shape variable $\gamma$ are slightly reduced.

A phonon approach with subsequent mapping onto bosons is developed for describing transitional nuclei spectra including the first backbending energy region. Quasiparticle random-phase approximation and its modification with minimum ground state correlations are employed to find $B_J$ phonons (spin $J>~4)$ and most collective quadrupole D phonons, respectively. Phonon functions and matrix elements of $B-D$ interaction are calculated with factorized quasiparticle forces. Besides the interaction mechanisms known in the interacting boson fermion model (IBFM) a new one is introduced that leads to three into one boson transformation. After mapping onto s-, d-, and $b_J$-boson space a boson Hamiltonian comprises IBM1 Hamiltonian, whose parameters depend on the presence or absence of $b_J$ bosons and are determined phenomenologically, and $b_J-d$ interaction with constants calculated microscopically inside phonon space. This approach applied to energy spectra and $B\left(E2\mathrm{}\right)\mathrm{}$ values in ${}^{126,128}\mathrm{Ba}$ and ${}^{130}\mathrm{Ce}$ gives reasonable agreement with experiment.

Superdeformed and highly deformed rotational bands in the $A\sim 60$ mass region are studied within cranked relativistic mean field theory and the configuration-dependent cranked Nilsson-Strutinsky approach. Both approaches describe the experimental data well. Low values of the dynamic moments of inertia $J^{\mathrm{}\left(2\right)\mathrm{}}$ compared with the kinematic moments of inertia $J^{\mathrm{}\left(1\right)\mathrm{}}$ seen both in experiment and in calculations at high rotational frequencies indicate the high energy cost to build the states at high spin and reflect the limited angular momentum content in these configurations.

Mass-energy distributions of the ${}^{270}\mathrm{Sg}$ $\mathrm{}(Z=106\mathrm{})\mathrm{}$ compound nucleus fission fragments have been studied in the reaction ${}^{22}\mathrm{Ne}{+}^{248}\mathrm{Cm}$ at two energies of neon projectiles, $E_{\mathrm{lab}}{(}^{22}\mathrm{Ne})=102\mathrm{}$ and 127 MeV, with the use of a two-arm time-of-flight spectrometer. The high-energy fission mode has been found at lower energies due to the manifestation of the spherical neutron shell $N\approx 82$ in the fission fragments.

A complete set of polarization transfer coefficients has been measured for quasielastic $(\overrightarrow{p},\overrightarrow{n})$ reactions on ${}^2\mathrm{H},$ ${}^6\mathrm{Li},$ ${}^{12}\mathrm{C},$ ${}^{40}\mathrm{Ca},$ and ${}^{208}\mathrm{Pb}$ at a bombarding energy of 346 MeV and a laboratory scattering angle of $22°$ ${(q}_{\mathrm{lab}}\approx 1.7\hspace{0.5em}{\mathrm{fm}}^{\mathrm{-}1}).\mathrm{}$ The spin-longitudinal $R_L$ and spin-transverse $R_T$ response functions are extracted within a framework of a plane-wave impulse approximation with eikonal and optimal factorization approximations. The theoretically expected enhancement of $R_L{/R}_T$ is not observed. The observed $R_L$ is consistent with the pionic enhanced $R_L$ expected by random-phase approximation (RPA) calculations. On the contrary, a large excess of the observed $R_T$ is found in comparison with $R_T$ of the quasielastic electron scattering as well as of RPA calculations. This excess masks the effect of pionic correlations in $R_L{/R}_T.$ The theoretical calculations are performed in a distorted-wave impulse approximation with RPA correlations, which indicates that the nuclear absorption effect depends on the spin direction. This spin-direction dependence is responsible in part for the excess of $R_T.$

The giant resonances of spin-isospin flip mode are studied by measuring the energy and angular distributions of ${\pi }^{+}$ electroproduced from ${}^7\mathrm{Li}$ and ${}^9\mathrm{Be}$ nuclei. Several strong ${\pi }^{+}$ groups are found and angular distributions of these groups are analyzed by distorted-wave impulse approximation calculations using the single particle shell model. The experimental cross section of the groups corresponds to an order of the charge exchange single particle transition strength, establishing them as spin-isospin flip giant resonances. The shell model nature of $(\gamma ,{\pi }^{+})$ results for ${1p}_{3/2}$ shell nuclei are summarized and presented together with previously published data. The obtained results are compared to previously published data for $({\pi }^{-},\gamma ),$ (n,p), ${(e,e}^{\prime }p),$ and $\mathrm{}(p,2p)\mathrm{}$ reactions. Strong transitions consistent with the giant resonance excitations from the ${1s}_{1/2}$ shell in the core and from the ${1p}_{3/2}$ valence shell are observed.

Inclusive measurements of the pion differential cross sections and analyzing powers have been carried out for the $p\overrightarrow{p}\mathrm{pn}{\pi }^{+}$ reaction at 420 and 500 MeV using the SASP spectrometer at TRIUMF. Pion energies from the onset of the continuum down to about 25 MeV were covered in the angular range from $23°$ to $100°$ (lab). Total cross sections of $0.750\pm 0.075\hspace{0.5em}\mathrm{mb}\mathrm{}$ and $2.77\pm 0.28\hspace{0.5em}\mathrm{mb}$ were determined for the $p\overrightarrow{p}\mathrm{pn}{\pi }^{+}$ reaction at 420 and 500 MeV, respectively. The experimental results are presented and discussed within the framework of a partial wave analysis. Theoretical predictions from a covariant one-boson-exchange model that includes final state interactions, provide a good description of the data. The pion spectra, in the region corresponding to low relative $\mathrm{np}$ energies, are also well described by a final state interaction model that uses the $p\overrightarrow{p}d{\pi }^{+}$ cross sections as input. Details of the determination of the background corrections and detector efficiencies will be discussed.

Formation cross sections of several fission products have been determined using recoil catcher technique followed by γ-ray spectrometry in ${}^{11}\mathrm{B}$ induced fission of ${}^{232}\mathrm{Th}$ at $E_{\mathrm{lab}}=72,$ 60, and 55 MeV. The data show significant admixture of fission from compound nucleus formed by complete fusion as well as targetlike nuclei formed by transfer reaction. Mass distributions for both the fissioning systems have been obtained using the systematics of charge distribution in low and medium energy fission. The mass distribution for complete fusion fission is broad, Gaussian whereas it is asymmetric for transfer induced fission. The evaporation residue cross sections of targetlike nuclei formed in ${}^{232}{\mathrm{T}\mathrm{h}(}^{11}{\mathrm{B},\mathrm{}}^{10}{\mathrm{B}\mathrm{e})}^{233}\mathrm{Pa}$ reaction were also measured. The measured evaporation residue cross sections and the decay probabilities of targetlike nucleus ${}^{233}\mathrm{Pa},$ calculated by the PACE2 code have been used to estimate the proton transfer fission cross sections which were found to be negligible compared to the total transfer cross section for all the projectile energies used. The transfer fission cross section is dominated by alpha transfer fission as inferred by measured forward to backward ratios for several fission products as well as $Q_{\mathrm{gg}}$ systematics for the probable transfer reactions. The proportion of transfer fission cross section to the total fission cross section was 15, 17, and 22 % at projectile energies of 72, 60, and 55 MeV, respectively.

The time-dependent mesh method is proposed as an efficient tool for a quantitative analysis of the Coulomb breakup of halo nuclei. The approach allows a treatment of breakup reactions in the nonperturbative regime. It avoids any multipole expansion for the Coulomb interaction between the projectile and the target. Moreover, it permits using more general trajectories allowing an estimation of postacceleration effects. This numerical technique is applied to the ${}^{11}\mathrm{Be}{+}^{208}{\overrightarrow{\mathrm{Pb}}}^{10}\mathrm{Be}{+n+}^{208}\mathrm{Pb}$ breakup reaction at 72 MeV per nucleon and is compared with experiment and with a previous calculation. Corrections due to the projectile deflection from a straight-line trajectory and to the neutron spin rotation are found to be weak for the specific collision parameters.

We investigate the validity of approximations that are sometimes made in calculating the nuclear induced breakup of halo nuclei. We find that a truncated coupled-channels calculations, in which the nuclear couplings between continuum states are ignored, gives almost the same result as a first-order calculation. However, the couplings are much too strong to justify these approximations. This is demonstrated in the frozen limit of a semiclassical description, where one can compare to exact results. We find in this limit that the one-neutron removal cross section of ${}^{11}\mathrm{Be}$ obtained in the approximate treatment is much larger than the exact result. This trend is also indicated at low energy by comparing a perturbative calculation of the breakup of ${}^8\mathrm{B}$ to the result of a more realistic treatment, which evolves the wave function of the valence proton essentially to all orders in the target fields.

We study quasielastic neutrino-nucleus scattering on ${}^{12}\mathrm{C}$ $\mathrm{and}{\hspace{0.5em}}^{16}\mathrm{O}$ within a continuum random phase approximation (RPA) model. The RPA equations are solved using a Green’s function approach with an effective Skyrme (SkE2) two-body interaction. Besides a comparison with existing calculations, we carry out a detailed study using various methods (Tamm-Dancoff approximation and RPA) and different forces (SkE2 and Landau-Migdal). We evaluate cross sections that may be relevant for neutrino nucleosynthesis.

The sensitivity of momentum distributions, recoil polarization observables, and response functions for nucleon knockout by polarized electron scattering to channel coupling in final-state interactions is investigated using a model in which both the distorting and the coupling potentials are constructed by folding density-dependent nucleon-nucleon effective interactions with nuclear transition densities. Elastic reorientation, inelastic scattering, and charge exchange are included for all possible couplings within the model space. Calculations for ${}^{16}\mathrm{O}$ are presented for 200 and 433 MeV ejectile energies, corresponding to proposed experiments at MAMI and TJNAF, and for ${}^{12}\mathrm{C}$ at 70 and 270 MeV, corresponding to experiments at NIKHEF and MIT-Bates. The relative importance of charge exchange decreases as the ejectile energy increases, but remains significant for 200 MeV. Both proton and neutron knockout cross sections for large recoil momenta, $p_m>300\mathrm{}\hspace{0.5em}\mathrm{MeV}/c$, are substantially affected by inelastic couplings even at 433 MeV. Significant effects on the cross section for neutron knockout are also predicted at smaller recoil momenta, especially for low energies. Many of the response functions and polarization observables for nucleon knockout are quite sensitive to the coupling scheme, especially those which vanish in the absence of final-state interactions. Polarization transfer for proton knockout is insensitive to channel coupling, even for fairly low ejectile energies, but polarization transfer for neutron knockout retains non-negligible sensitivity to channel coupling for energies up to about 200 MeV. The present results suggest that possible medium modifications of neutron and proton electromagnetic form factors for $Q^2\gtrsim 0.5\hspace{0.5em}(\mathrm{GeV}{/c)}^2$ can be studied using recoil polarization with relatively little uncertainty due to final-state interactions.

The fragmentation of ${}^{14}\mathrm{B}$ and ${}^{15,17,19}\mathrm{C}$ have been obtained through the interaction of these nuclei with a tantalum target nucleus at various energies. The Coulomb dissociation cross section has been analyzed within a direct fragmentation model. The theory of diffraction dissociation and diffraction stripping has been incorporated within the framework of the present model to show the nuclear effect in the process of breakup. The theoretical results have been compared with recent experimental works on these neutron-rich drip line nuclei.

The role of the three-body wave function in the scattering of pions from polarized ${}^3\mathrm{He}$ is studied. It is found that for the case of the asymmetry from ${\pi }^{+}$ scattering, the inclusion of the D state can be very important, changing the asymmetry calculated by as much as a factor 2–3. The ${\pi }^{-}$ scattering asymmetry is altered very little.

A chiral symmetry model for nuclear matter is extended to finite temperature and then used to study the Coulomb instability of hot nuclei. The role of the $\rho$ meson degree of freedom is discussed. The calculated limiting temperature is compared with the results obtained from other theories and experiments.

The variation of two-nucleon photoemission cross sections and photon asymmetries over kinematic ranges defined by typical detector acceptances is investigated. A Monte Carlo sampling technique, applied to theoretical calculations based on an unfactorized, distorted-wave approach, is used to obtain average cross sections and photon asymmetries. Comparisons are made with calculations evaluated at one central point per bin. Significant differences between the averaged calculations and the central values are observed for ${}^{12}\mathrm{C}(\gamma ,np)$ cross sections, while for $(\gamma ,pp)$ the differences are much smaller. The averaged photon asymmetries for both reactions are consistent with central values.

The effect of altered hadron masses is studied for its effect with regard to final-state hadronic observables. It is shown that the final phase space densities of pions and kaons, which can be inferred experimentally, are sensitive to in-medium properties of the excited matter at earlier stages of the collision, but that the sensitivity is significantly moderated by interactions that change the effective numbers of pions and kaons during the latter part of the collision.

We study the effects of strict conservation laws and the problem of negative contributions to final momentum distribution during the freeze-out through 3-dimensional hypersurfaces with spacelike normal. We study some suggested solutions for this problem, and demonstrate it in one example.

The bremsstrahlung produced when heavy nuclei collide is estimated for central collisions at the Relativistic Heavy Ion Collider. Bremsstrahlung photons with energies below 100–200 MeV are sufficient to discern the gross features of the space-time evolution of electric charge, if they can be separated from other sources of photons experimentally. This is illustrated explicitly by considering two very different models, one Bjorken-like, the other Landau-like, both of which are constructed to give the same final charge rapidity distribution.

We compute the Coulomb effects produced by an expanding highly charged fireball on the momentum distribution of pions. We compare our results to data on $\mathrm{Au}+\mathrm{Au}$ at $11.6A\hspace{0.5em}\mathrm{GeV}$ from E866 at the BNL AGS and to data on $\mathrm{Pb}+\mathrm{Pb}$ at $158A\hspace{0.5em}\mathrm{GeV}$ from NA44 at the CERN SPS. We conclude that the distortion of the spectra at low transverse momentum and midrapidity can be explained in both experiments by the effect of the large amount of participating charge in the central rapidity region. By adjusting the fireball expansion velocity to match the average transverse momentum of protons, we find a best fit when the fireball radius is about 10 fm, as determined by the moment when the pions undergo their last scattering. This value is common to both the AGS and CERN experiments.