Table of contents

Calculations of the various charge modes in weak pion production by neutral currents in the Delta region are made using a PCAC approach and compared with results from Argonne and CERN.

The authors show that correlation effects as observed in large p_T pion events can increase the rates for psi psi , psi psi ', psi ' psi ' production by two orders of magnitude. The same effects should reveal themselves in a comparison of high p_T pion distributions for events with and without a heavy particle.

The thresholds for pion condensation in terms of the nucleon-nucleon interaction amplitude are calculated for both neutral and charged channels in the spherical nuclei from ¹⁶O to ²⁹⁸114. In light nuclei, where the repulsive constant g^- decreases (i.e. when the density increases), the mode J^pi =0^- is the first to become unstable. In heavy nuclei, the transition into a pion-condensed state is similar to that in infinite systems, but there are differences due to shell effects.

The total potential energy surfaces of several thallium, gold, iridium and rhenium odd-mass isotones are calculated microscopically as functions of the quadrupole deformation epsilon ₂, when the odd protons occupy definite orbitals. The nuclear shapes and the static equilibrium deformations of these nuclei are deduced from the results of these calculations for the proton orbitals nearest to the Fermi level.

With the aid of simple vector meson dominance the authors extract from experiment the couplings of the psi ' psi eta complex. The predictions for these couplings of the Han-Nambu colour theory are derived and shown to be in conflict with the phenomenological values. Possible resolutions of this discrepancy in terms of more sophisticated versions of vector dominance are discussed.

The authors present a realistic eikonal model for spin-dependent proton-proton elastic scattering which yields a fairly good description of the cross section data from p_lab=5.5 GeV/c up to ISR energies at both small and large angles. Single polarization and spin correlation tensors have been calculated and compared with low-energy data; they also give some interesting predictions at high energy. They present s-channel helicity amplitudes at p_lab=6 GeV/c. The model also describes antiproton-proton elastic scattering and, for example, predicts a dip in the differential cross section at -t=0.9 (GeV)² for p_lab=25 GeV/c.

A lower bound is calculated for the pionic contribution to the muon magnetic moment. The bound uses data on the form factor in the space-like region and the 'charge radius' of the pion. The lower bound is 22.8*10^-9 which is within a factor of two of the 'experimental' value.

The author reviews recent developments in, and the present status of, the unified gauge theories of weak and electromagnetic interactions. Specifically, he discusses the accommodation of the newly discovered heavy lepton within these theories and the implications for new quarks and/or right-handed currents. This sheds new light on the old problem of incorporating CP-violation in a natural way. In addition, reviews new work on the detection of the Higgs scalars, manifestations of the neutral currents and the origin of the mod Delta I mod =¹/₂ rule.

Results from the Gargamelle experiment on neutrino production of events with muon, electron and V⁰ in the final state are presented together with a complete study of the background. Also given are results of a search for charm decays via hadronic modes.

The nuclear matrix elements involved in the neutrinoless double beta decay of ⁴⁸Ca were calculated using a finite Fermi system theory. A lepton non-conservation parameter eta <or approximately=6*10^-5 and a neutrino mass m_v<or approximately=50 eV were deduced.

The _Lambda ³H binding energy is investigated with rank-2, two-body potentials for all three pairs of particles. The Lambda -d doublet s-wave scattering amplitude is obtained for a Faddeev-type multiple scattering formalism. Some Lambda N potentials which have repulsive cores are investigated. The repulsive potential range (0.2 fm) has been kept fixed in all three channels. The authors observe that the potential derived from the experimental findings of Alexander et al. gives consistently good results and thus Alexander et al. (1968) gives consistently good results and thus proves to be a good approximation for the Lambda N charge symmetric (CS) potential.

The charge symmetry breaking (CSB) component of the nuclear forces yields the charge asymmetric term E_a(N-Z)/A in the nuclear binding energy of nuclear matter. Calculations performed with several models of CSB nuclear forces, and accounting for the strong short-range two-body correlations, give E_a approximately=-0.2 MeV at the normal nuclear density. The charge asymmetry of the effective nucleon-nucleon interaction is determined primarily by the CSB nuclear forces at the neutron excess, observed in finite nuclei. The exclusion principle and dispersion (self-consistency) effects of the nuclear medium decrease this charge asymmetry.

An analytic continuation of the S-matrix into the complex l plane is performed. A smooth cut-off representation for the S-matrix is parametrized so that its pole nearest to the real axis dominates the elastic scattering of strongly absorbed particles. An application to alpha particle elastic scattering data gives information about the nature of the pole trajectory. A description of the back-angle anomalies, their energy dependence and the isotope effect is presented.

Two states in ⁵⁹Cu populated by the reaction ⁵⁸Ni(p, gamma ) at proton energies of 3547 and 1833 keV have been studied. An investigation of the gamma ray transition between the resonance states and the gamma ray decay of the lower energy resonance has yielded Gamma _gamma / Gamma =0.86+or-0.04 and (2J+1) Gamma _gamma Gamma _p/ Gamma =0.046+or-0.005 eV for the lower resonance. The spin of the lower resonance (E_x=5219 keV) has been deduced to be ⁹/₂ and therefore the total width of the state is 0.038+or-0.009 eV, corresponding to a lifetime tau =17.5+or-4.1 fs. The Doppler shift attenuation method used to determine the lifetime of this state yields the values 13.5+or-2 fs and 16+or-2 fs. It is concluded that, within experimental error, there is agreement between observation and standard ion energy loss theory for the case of Cu recoiling in Ni.

The low-lying negative parity levels in ⁶¹Ni up to 1610 keV were studied by means of Coulomb excitation of ⁶¹Ni with 3-4.5 MeV protons and 4.5-5.5 MeV ⁴He ions. The yields of the gamma rays were measured with a Ge(Li) detector. Gamma ray angular distribution measurements established a spin value of ⁵/₂ for the 1014 keV state and from these measurements multipole mixing ratios for seven gamma transitions were found for the first time. The reduced E2 and M1 transition probabilities were determined for the 283, 656, 909, 1014, 1100, 1132 and 1185 keV states.

The differential cross sections for inelastic scattering of 12 MeV deuterons from ¹⁰²Ru and ¹⁰⁴Ru have been measured. Several new levels were located in both nuclei. For the one-phonon 2⁺ and 3^- states the observed angular distributions have been compared with predictions from DWBA theory.

The decay of ²³³U was examined using Ge(Li) and Si(Li) gamma ray spectrometers in singles and coincidence configurations. Chemical separation of the contaminating daughter products was effected through anion exchange. Of the 117 gamma rays observed here, 26 are reported for the first time. Four new levels, having excitation energy 235, 340, 436.7 and 478.7 keV, are proposed for ²²⁹Th. The lowest-lying levels are discussed within the context of the Nilsson model including Coriolis mixing effects.