Table of contents

Calculations for ⁷Li, ⁹Be, ¹¹B, ¹³C, ¹⁴C, ¹⁴N and ¹⁶O show a systematic analogy in the excitation spectra of several low-momentum transfer (q<or approximately=1 fm^-1) reactions. In this way, the magnetic quadrupole resonance (T_>=T_GS+1) was safely traced in the 1p-shell nuclei.

The experimental cross section ratio of ⁷Li (p, p'd) and ⁷Li (p, nd) large-angle quasifree scattering at T_p=670 MeV is compared with theoretical estimates based on the cluster model of ⁷Li.

Central collisions between He, C and O projectiles in the energy range 0.2 GeV/nucleon to 4.2 GeV/nucleon and Ag and Br targets in 4 mu nuclear track detectors (AgCl crystals and nuclear emulsion) have been investigated. The measurements were directed towards effects at the target site where Mach shock phenomena were expected to be seen. Angular and energy spectra of target fragments partitioned into two groups with Z=1 and Z>or=2 have been measured up to energies of 30 MeV/nucleon. The angular distributions of the He group from events with a high number of slow secondaries show characteristic peaks varying with the projectile energy in a way consistent with the Mach shock model. The corresponding energy spectra extend to higher values in the angular region of the peaks, as expected from the model.

A proof is given of the theorem that, in chiral-invariant vector-gluon theories, the spontaneous generation of fermion mass is associated with zero-mass pseudoscalar bosons. The proof relies heavily on the proper determination of Bethe-Salpeter kernels which respect the Ward identities correctly, and is exact to the extent that the propagator is self-consistently truncated. Given this result, we survey the implications of PCAC for the quark-gluon model.

The differential cross section for e⁺e^- to l⁺l^- via one-photon and two (or more) vector boson exchange is evaluated for arbitrary states of electron and positron polarisations. The asymmetry effects and the total cross section in e⁺e^- to l⁺l^- are computed for some unified models of weak and electromagnetic interactions.

It is shown that the Householder method can be considered as a Lanczos method, with the same properties for the convergence of the eigenvalues. An application to a proton two-particle-neutron two-hole shell-model calculation in ¹³²Te is carried out. Moreover, in the specific case of the J^pi =2⁺ level, the convergence properties for both methods are studied in detail.

Analytical expressions for the projected-BCS energies and reaction transition rates among the isovector pairing collective states are obtained by the recognition of symmetry properties in a class of BCS wavefunctions. As a consequence, a simplified generator coordinate treatment is suggested.

A new method of calculating nuclear charge and matter distributions is described. It uses the sum of the squares of single-particle wavefunctions to give a first approximation and then iterates the proton and neutron densities in a formalism that takes into account the interaction between these densities and between the valence and core nucleons. The single-particle potentials are adjusted to give the experimental centroid separation energies and configuration mixing is included using shell-model occupation probabilities. The method is applied to the core nuclei ¹⁶O and ⁴⁰Ca, to their isotopes and to other nuclei in the sd and pf shells. Detailed comparisons are made with all available experimental data on nuclear charge and matter distributions.

A simple energy-dependent optical potential is obtained which describes proton scattering from light nuclei in the energy range 50-160 MeV. The properties of the potential are compared with other available phenomenological potentials and with theoretical predictions. Some distorted-wave calculations for the (p, 2p) reaction are included to show the sensitivity to the choice of optical potential.

The direct nuclear reaction C(p,3p) at 640 MeV has been studied in an exclusive experiment. The measuring conditions were chosen in accordance with the kinematics of the two-nucleon quasifree knock-out. Phenomenological models assuming proton scattering on proton pairs are in qualitative agreement with the data.

The energies and relative intensities of the primary gamma rays from the ⁴⁴Sm(n, gamma )¹⁴⁵Sm reaction have been measured with a Ge(Li) pair-formation gamma -ray spectrometer from 3.0-7.2 MeV. The neutron separation energy of ¹⁴⁵Sm was found to be 6757.1+or-0.3 keV. A comparison of the measured strengths of excitation of levels in ¹⁴⁵Sm in the (n, gamma ) and (d,p) reactions reveals that they are strongly correlated. These results are discussed in terms of a number of simple neutron-capture reaction mechanisms.

Differential cross sections for alpha-particle elastic and inelastic scattering on ⁶Li have been measured in the angular range from 9 degrees to 165 degrees . The elastic differential cross section has been analysed with various models including a phenomenological parametrisation of the nuclear amplitude with its zeros.

Isomer ratios have been measured in Sb and Te isotopes prepared in the ¹¹⁵In( alpha ,n), ¹¹⁵In( alpha ,3n), ^{118,120,122,124}Sn( alpha ,pn), and ¹²⁰Sn( alpha ,3n) reactions, using a range of bombarding energies between 16.6 and 38.4 MeV. In most of the product nuclei the isomer ratios are smaller than the predictions of the sharp cut-off model, showing that the isomer is less than 100% efficient in trapping high-spin products. The variation of isomer ratio with bombarding energy is described by a simple expression for the trapping efficiency.

The first 2⁺ states of the target nuclei ⁴⁶Ti, ⁴⁸Ti and ⁵⁸Ni were populated by inelastic scattering of ⁷Li with beam energies just above the Coulomb barrier. Differential cross sections of elastic and inelastic scattering were measured. Coulomb-nuclear interference in the inelastic channel of each reaction was observed. Analyses were performed in terms of the optical model of elastic scattering and the DWBA. Optical potentials were deduced.

The neutron-deficient isotope ⁶⁶Ge has been studied using gamma-ray spectroscopy techniques. States in ⁶⁶Ge were populated using the ⁵⁸Ni(¹⁰B,pn gamma )⁶⁶Ge reaction at bombarding energies of 28.5, 29 and 30 MeV. A decay scheme has been established from the results of gamma-gamma and neutron-gamma coincidence experiments performed at a beam energy of 28.5 MeV. Angular distributions were measured at beam energies of 28.5, 29 and 30 MeV, and linear polarisations were measured at 28.5 MeV. The analysis of these data yields spin-parity assignments of 1694 keV (2⁺), 2175 keV (4⁺), 3686 keV (4⁺,5^-), 4208 keV (6⁺,7^-) and a probable 6⁺ assignment to the 3657 keV level. Spin restrictions are also placed on several other levels. The lifetimes of the 958, 1694 and 4208 keV levels are deduced from a recoil-distance-method experiment, performed at a beam energy of 29 MeV, to be 5.3+or-1.0 ps, 6.5+or-2.5 ps and 295+or-40 ps respectively. A limit of less than 3 ps has also been placed on the lifetime of the 2175 keV level.