High-spin states of ${}_{}{}^{143}{}_{}{}^{}\mathrm{Nd}$ have been studied using the ${}_{}{}^{130}{}_{}{}^{}\mathrm{Te}$${(}^{18}$O,5n) reaction at 85 MeV. The yrast states observed up to a tentatively assigned spin of 45/2 can be described in a remarkably simple way by the weak coupling of an ${\mathit{f}}_{7/2}$ neutron to the ${}_{}{}^{142}{}_{}{}^{}\mathrm{Nd}$ core nucleus. Our results demonstrate that ${}_{}{}^{143}{}_{}{}^{}\mathrm{Nd}$ is one of the best known examples of weak coupling at high angular momentum.

We present a microscopic calculation of the transverse response function for the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(e,${\mathit{e}}^{\mathcal{’}}$) reaction in the quasielastic domain. Our results clearly demonstrate the necessity of including RPA correlations if one wants to describe correctly both position and shape of the quasielastic peak. Building upon the RPA results, we then discuss the importance of the 2p-2h background, which confirms itself to be the dominant mechanism responsible for achieving agreement between theory and experiment at the peak and in the higher energy region. Finally, the results are discussed in the context of the latest relativistic calculations and experimental work.

The multiphonon structure is shown for the O(6) limit of the interacting boson model. The phonon states are created by the O(6) quadrupole operator with proper symmetrization. All the σ=N states can be described in this scheme in terms of phonon quanta and two-phonon anharmonicity, while the ground state is γ unstable. This structure is carried over into higher-lying σ<N states.

The reaction pp→πd is studied in a relativistic meson rescattering model. For 1.3<${\mathit{T}}_{\mathit{p}}$<2.4 GeV the differential cross section and the asymmetry are calculated and compared to experiment. The model introduces simple form factors for the leading πN partial waves which depend on the virtuality of the exchanged mesons, π and ρ. All remaining input is derived from experimental constraints. The data can be described by energy-independent form factors. The asymmetries are sensitive to pp distortion factors and further details of the model.

Phase shifts for α+nucleon scattering generated by a multichannel resonating-group method (RGM) model of the five-nucleon system are subjected to iterative-perturbative ‘‘mixed-case’’ inversion for energies below the reaction threshold. The resulting phase-equivalent potentials are compared with local potentials calculated from the inversion of empirical phase shifts. A strong similarity is revealed between the two sets of potentials, most notably in the description by a parity- and energy-dependent local potential. In particular, the RGM-derived and empirical potentials share a distinctive form of parity dependence in which the odd-parity component is of greater radial extent. Comparison with potentials representing single-channel RGM phase shifts exhibits the importance of the coupled channels in terms of local potentials. The relative wave functions derived from RGM are very different from those for the phase-equivalent local potentials. Connections are made with general nucleon-nucleus scattering.

The inverse β decay ${}_{}{}^{205}{}_{}{}^{}\mathrm{Tl}$(ν,e${)}^{205}$Pb can be used to investigate the solar neutrino flux averaged over the last several million years. The inverse β decay proceeds dominantly via the 2.3 keV level of the ${}_{}{}^{205}{}_{}{}^{}\mathrm{Pb}$ and an accurate estimate of the cross section depends on our knowledge of the structure of the 2.3 keV level. We have made the first measurement of the half-life for the decay of the 2.3 keV level to the ${}_{}{}^{205}{}_{}{}^{}\mathrm{Pb}$ ground state. Our result is ${\mathit{T}}_{1/2}$=24.2±0.4 μs and can be used to improve our knowledge of the structure of the two ${}_{}{}^{205}{}_{}{}^{}\mathrm{Pb}$ states.

The nucleus ${}_{}{}^{64}{}_{}{}^{}\mathrm{Zn}$ is predicted to be γ unstable at low spin, but γ stable at spins of 8ħ and above. In order to see if this structural change is manifested in the decay scheme, this nucleus has been studied via γγ, recoil-γ, and recoil-γγ coincidence techniques using the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{54}$Fe,2p) at 155 MeV. Twenty new levels have been observed with spins of up to 12ħ, but no evidence is observed for the predicted onset of gamma stability.

The projectile-target system ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$${+}^{58}$Ni has been used to produce the neutron deficient N=50 isotones ${}_{}{}^{93}{}_{}{}^{}\mathrm{Tc}$, ${}_{}{}^{94}{}_{}{}^{}\mathrm{Ru}$, and ${}_{}{}^{95}{}_{}{}^{}\mathrm{Rh}$ at high angular momentum. The multidetector array NORDBALL including particle selection was used. A large number of new levels were found in all three nuclei. Most of them can be interpreted as states with a neutron particle-hole excitation across the N=50 shell gap, coupled to lower valence-proton configurations. Some of the observed levels above 11 MeV probably correspond to states with two neutrons excited across the shell gap.

High spin states in the N=51 nucleus ${}_{}{}^{95}{}_{}{}^{}\mathrm{Ru}$ were populated and studied using the reaction ${}_{}{}^{64}{}_{}{}^{}\mathrm{Zn}$${(}^{35}$Cl,3pn${)}^{95}$Ru at a beam energy of 140 MeV. Gamma-ray intensities and gamma-gamma coincidences were measured. Multipolarities of the transitions were extracted assuming stretched transitions. Forty new transitions have been found. The positive and the negative parity bands have been extended up to spins of 43/$2^{+}$ and 39/$2^{\mathrm{-}}$, respectively. The level scheme can be well understood up to moderate spins in terms of spherical shell model calculations within a limited configuration space. A weak coupling scheme in which a 2${\mathit{d}}_{5/2}$ neutron is coupled to the excited ${}_{}{}^{94}{}_{}{}^{}\mathrm{Ru}$ core was found to work reasonably well and reproduced the main features of the observed ${}_{}{}^{95}{}_{}{}^{}\mathrm{Ru}$ yrast spectrum. A more rigorous approach to understanding the structure of these high spin states is the breaking of the N=50 neutron core. The top three transitions in the positive parity band (492, 599, and 744 keV) appear to be an indication of collective behavior.

The ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$(t,p${)}^{12}$Be reaction has been studied with 15- and 17-MeV triton beams. At 17 MeV, angular distributions were measured for five low-lying states, and disorted-wave Born-approximation calculations were used to analyze the data. Contributions from ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$(g.s.)⊗(sd${)}^2$ and complete 1p-shell wave functions were investigated. Comparsion is made with (sd${)}^2$ states in ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{16}{}_{}{}^{}\mathrm{C}$.

High-K bands have been observed in the ${}_{}{}^{166,167,168}{}_{}{}^{}\mathrm{Yb}$ isotopes following the ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sn}$${(}^{48}$Ca,xnγ) reaction. The ν${\mathit{h}}_{11/2}$ band in ${}_{}{}^{167}{}_{}{}^{}\mathrm{Yb}$ has been extended to higher spins. The high-K bands in the even-even isotopes were observed for the first time and show very high B(M1)/B(E2) ratios. Configuration assignments for the new bands are proposed. The results are interpreted within the Tilted Cranking model.

Mean lifetimes of levels in ${}_{}{}^{28}{}_{}{}^{}\mathrm{Al}$ have been measured using the Doppler-shift-attenuation (DSA) method in conjunction with the reaction ${}_{}{}^2{}_{}{}^{}\mathrm{H}$${(}^{27}$Al,p${)}^{28}$Al. The lifetime values were determined for 26 bound levels below the excitation energy of 6.32 MeV. The lifetimes of eight levels are reported for the first time. The targets were prepared by implanting ${}_{}{}^2{}_{}{}^{}\mathrm{H}$ into Si and ${}_{}{}^{20}{}_{}{}^{}\mathrm{implanted}$ Au substrates. Computer simulations with the Monte Carlo method and experimental stopping power were used in the DSA analysis. Measured mean lifetime values are compared with predictions of the universal sd-shell model.

The structure of low-lying levels in odd-mass Te isotopes (115≤A≤131) is discussed in the framework of the quasiparticle-phonon model. In addition, the properties of ${}_{}{}^{131}{}_{}{}^{}\mathrm{Te}$ are also investigated by means of three-particle cluster-phonon coupling, where the pairing force is taken as the residual particle-particle interaction. Excitation energies and spectroscopic factors are calculated and compared with the experimental data.

We have described a seniority conserving mapping procedure from the shell model space to the boson-quasifermion space for odd nuclei within the framework of the Otsuka-Arima-Iachello mapping which is suitable in regions where seniority is a good quantum number. We show that, when a number of levels are allowed to the odd fermion in the interacting boson-fermion model (IBFM), one can use the dynamic symmetry, if present, to unambiguously find out the parameters in the IBFM Hamiltonian. As a simple example of the technique, we have discussed the case of ${}_{}{}^{59}{}_{}{}^{}\mathrm{Ni}$ where an approximate ${\mathrm{U}}_{\mathit{B}+\mathit{F}}$(5)×${\mathrm{SU}}_{\mathit{F}}$(2) is known to exist.

The BCS theoretical values of the moments of inertia of even-even nuclei are systematically smaller than the experimental ones by a factor of 10–40%. This long-standing discrepancy disappears in the particle-number-conserving treatment for the cranked shell model, in which the blocking effects are taken into account exactly. The calculated moments of inertia satisfactorily reproduce the experimental data covering a large number of rare-earth even-even nuclei, whose deformations and single-particle states are well characterized (Lund systematics). The pairing interaction strength G is unambiguously determined by the even-odd mass difference. The reduction of the moment of inertia due to the antialignment effect of pairing interaction is discussed and no systematic excessive reduction is found.

We study the shell closure properties of the even-even neutron-deficient Pt, Hg, and Pb isotopes using a deformed relativistic mean field formalism. The ground state structures are investigated by comparing the prolate, oblate, and spherical solutions. Many of the nuclei are considerably deformed in their ground state configurations. Studies of the quadrupole and the hexadecapole moments, density distributions, and the single-particle level structure clearly indicate that some of the neutron-deficient isotopes having proton number Z=82 do not behave as good magic nuclei.

The total microscopic correction to the deformation energy of the rare-earth even-even nuclei is evaluated by a method that takes simultaneously into account the shell and pairing effects. The single-particle basis used is the Woods-Saxon potential. The results are in good agreement with experiments and represent an improvement as compared to the usual Strutinsky and BCS methods.

The properties of cold nuclear matter are investigated in a class of nonlinear mean field σ-ω theories which includes a density dependence of the meson parameters. This dependence can be both explicit and implicit through the effective nucleon mass. We apply the theory to the case of an interaction between the scalar and the vector mesons and investigate the properties of neutron stars using the resulting equation of state.

We simplify a treatment of pion distortions using a separable expansion of optical potential in momentum space. We use this method to gain insight into the role of distortions in isoelastic pion charge-exchange scattering within the framework of the isospin-invariant optical model. The method provides an analytic procedure for calculating external distortions for single- and double-charge-exchange scattering. This allows us to analyze separately the role of on- and off-shell pions in distortions for each partial wave. Results for sequential scattering at 50 MeV for the reaction ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$(${\mathrm{\pi }}^{+}$,${\mathrm{\pi }}^{\mathrm{-}}$${)}^{14}$ O are presented. It is shown that the external distortions give a small enhancement in forward directions and reduce the differential cross sections at large angles.

Calculations for semi-infinite nuclear matter within the relativistic Hartree approximation have been performed utilizing the nonlinear σ-ω model. We investigate the structure of the nuclear surface, i.e., the surface energy and the surface thickness, in its dependence on the properties of uniform nuclear matter in a systematic manner. We establish criterions for the selection of a relativistic mean-field parametrization following from the experimentally well determined, nuclear surface properties. In this respect, we discuss some currently used parameter sets. In addition, the accuracy of the semiclassical Thomas-Fermi approximation compared with the fully quantal approach is investigated. We close with some studies on density distributions (skewness parameter, Friedel oscillations, and the influence of the spin-orbit potential) and the nuclear curvature energy.