Table of contents

The large spin-dependence of the proton-proton total cross section data for laboratory momenta less than 3 GeV/c is shown to be consistent with the interference between the pi and rho exchange contributions to Delta production.

A satellite peak resolved on the high-energy side of K_alpha and K_beta X-ray groups excited by 20-50 MeV protons in tantalum is studied, and its production mechanism is determined to be the result of de-excitation by internal conversion of the product nuclei from (p,xn) reactions.

It is necessary to invoke a fast-developing air shower model to interpret the measurements of signal rise-times observed at about 500 m from the axis of extensive air showers (EAS) with primary energy near 3*10¹⁷ eV. Fluctuations in these rise-times indicate that the primary cosmic rays at this energy consist of at least 40% protons.

It is shown, for a certain class of supersymmetric theories, that if supersymmetry is unbroken in the tree approximation then it remains unbroken when the one-loop quantum corrections are included. The authors use a simple model to illustrate the above theorem and also to demonstrate that at least some of the massless scalars which plague supersymmetry theories are pseudo-Goldstone bosons.

A study of 54930 events of type pp to pi ⁺ pi ⁺ pi ^- pi ^- pi ⁰ shows evidence for two nearly mass degenerate enhancements in the omega pi mass plots at a mass near to 1200 MeV/c². This result is in agreement with that reported from annihilations at rest by Frenkiel et al. (see Nucl. Phys., vol.B47, p.61 of 1972).

The validity of the density-matrix expansion (DME) is investigated using two different interactions: the Brink and Boecker (1967) B1 force and the Campi-Sprung (see Nucl. Phys., vol.194A, p.401 of 1972) G-O force. Simple parametrizations of the Hamiltonian density are discussed and the connection between the DME and Skyrme-like force is examined.

The (-1)^A energy states of ⁵⁰Ti, ⁵¹V, ⁵²Cr, ⁵³Mn, ⁵⁴Fe and ⁵⁵Co are calculated within the spherical shell-model framework, assuming a ⁴⁸Ca closed core and the (Z-20) valence protons to occupy orbitals in the complete 0f-1p major shell. Both the schematic surface delta interaction (SDI) and the realistic Kuo-Brown (KB) force are used as effective two-body interactions, the interaction strength in the first case being smoothly decreased with increasing mass number. At least 40 experimental levels are well accounted for and the resultant wavefunctions are used to calculate E2 transition rates. Although the two interactions render very similar results, the KB spectra are generally too expanded and the B(E2) values too small. The failure of the present calculations to account for the low-lying 0⁺ excited states in the even-mass nuclei points to the necessity to allow for 0f_7/2 neutron-shell excitations.

The theory of gamma -L_x directional correlations is reformulated and generalized in order to take into account admixtures of different multipolarities. As an application, the anisotropy in the gamma -L_x angular correlation following the decay of ²⁰⁷Bi is calculated and compared with recent experimental results.

The internal bremsstrahlung spectra emitted in the beta decays of ⁴⁵Ca and ³⁵S were measured using a multichannel NaI(Tl) scintillation spectrometer with a standard geometrical arrangement. After making all the necessary corrections, the experimental results were compared with theory.

The excited states of ²⁵Mg have been studied by inelastic electron scattering in the momentum transfer range 0.3 to 1.15 fm^-1. The reduced transition probabilities and transition radii were measured for seven levels below 4.1 MeV excitation energy and the transition probabilities are shown to be more precise than existing measurements. A search for the hexadecupole strength to the ¹¹/₂⁺ levels in the vicinity of 5-6 MeV excitation energy was also carried out. The applicability of an extended Nilsson-model description for the ground-state band of ²⁵Mg was also investigated by comparison with the known electromagnetic strengths, and, more crucially, by comparison with the measured form factors.