Table of contents

It is shown that the experimental accuracy with which e- mu universality is verified allows much bigger 'leakage' of the proton quark weak-coupling constant to the quark b than it is admissible by the uncertainties in the Cabibbo universality (G_mu ²=G_beta ²+G_{Delta S=1}²) itself. Some theoretical possibilities created by deviations from these universalities are indicated.

Particle- gamma angular correlations following Coulomb excitation of ¹⁴⁹Sm and angular distributions following the ¹⁴⁸Nd( alpha ,3n)¹⁴⁹Sm reaction have been measured. The spin of the 591 keV level has been uniquely assigned as ⁹/₂^-, in agreement with predictions of a particle-vibration intermediate coupling model. The usefulness of the technique in resolving spin ambiguities is discussed.

The hydrodynamic two-fluid model of Steinwedel and Jensen (1950) for the explanation of the isovector giant dipole resonance energies is extended to include viscosity and is generalized to isoscalar and isovector resonances of arbitrary multipolarity. It is thus possible to calculate the energies as well as the widths of various giant resonances and to compare them with experimental data. Viscosity enters solely by the Navier-Stokes viscous forces and not by a phenomenological linear frictional force as has been previously employed.

A new multispinor superfield of second rank is constructed which satisfies the Bargmann-Wigner (1946) equation and describes particles of spin ranging from ¹/₂ to ³/₂. A supersymmetric Lagrangian is written with the help of an auxiliary superfield which vanishes in the absence of interaction. The resulting Green function for the spin ³/₂ multispinor is the same as that obtained by Guralnik and Kibble (1965) and Chang (1967). Finally an interaction with a scalar superfield is studied in perturbation theory and shown to be non-renormalizable.

The pattern of spontaneous symmetry breaking is investigated in supersymmetric SU(N) gauge theories for the quark and adjoint representations of SU(N).

For the infra-red cancellation mechanism to work in the context of analytic regularization it is necessary to replace the virtual photon propagator (k²)^-1 by - Gamma (z)(-k²)^-z and the photon phase-space by the continuous mass distribution 2 pi integral d⁴k theta (k_o) theta (k²)/ Gamma (1-z)(k²)^z. The cancellation for charged-particle scattering in a weak external field is shown.

A finite value for the neutrino electromagnetic form factor is obtained using 't Hooft's regularization procedure. This is then used in calculating the decay width Gamma ( psi to nu nu ). The value of the decay width is found to be quite important from the experimental view point.

Using a recoil-distance technique, the g-factor of the short-lived 1.98 MeV 2⁺ level in ¹⁸O has been deduced from the time-differential hyperfine perturbation of the nuclear alignment following the reaction H(¹⁸O,p)¹⁸O* on recoil into vacuum at high velocity. From the observed hyperfine frequency, due to the 1²S_1/2 field in one-electron ions, the value deduced was mod g mod =0.287+or-0.015. A simultaneous time-of-flight determination of the lifetime of the state gave a value for tau _m of 2.99+or-0.12 ps. Interpretation of the present data, combined with the results of earlier experiments of a similar kind, leads to the conclusion that hydrogen-like oxygen ions are formed predominantly in low-lying states, at velocities close to the maximum in the yield of one-electron ions.

The energy dependence and radial behaviour of the real and imaginary part of the nucleon optical potential is obtained by generalizing a model so far applied to infinite nuclear matter. The method is based on the determination of the imaginary part by its relationship to the total reaction cross section. For the calculation of this quantity the irreducible vertex and the target autocorrelation function of the density fluctuations are needed. The real part emerges from a dispersion relation which contains an energy-dependent contribution and the Hartree-Fock potential. The dispersion relation has been applied in two versions. In the so-called subtracted form-where the extreme energies play a minor role-a phenomenological homogeneous term is used. The calculations were performed using a non-singular force. The agreement with the phenomenological potentials is satisfactory using the subtracted dispersion relation; in the non-subtracted version too strong real potentials ( approximately 10-15 MeV) are obtained.

For pt.VI see ibid., vol.1, p.935 (1975). Spectroscopic factors have been calculated for nuclei in the sd shell. The shell-model wavefunctions were calculated using the fitted interaction of Preedom and Wildenthal (1972). The agreement with existing experimental data was in general good both for stripping and pick-up reactions.

The decay of ¹²⁶I was studied with a large Ge(Li) detector. Several transitions previously assigned to the ¹²⁶I decay were not confirmed.

A study of the electromagnetic interactions of muons of energy 7-700 GeV in a thick iron absorber has been made with the Durham spectrograph, MARS. Whilst it is never possible in such an interaction experiment to study one of the interaction processes alone, by classifying the experimental data into various ranges of muon energy and energy transfer it is shown that one of the interaction processes can be made to dominate. The measured interaction probabilities agree within the limits of experimental error with those calculated theoretically for energy transfers of 1-100 GeV from muons of energy 7-700 GeV.