An expression for the differential cross-section of pion production by protons on nuclei is built up using the impulse approximation. It assumes the knowledge of free nucleon-nucleon pion production and takes account of the internal nucleon momentum distribution, the Coulomb potential, and the absorption effects of the incoming protons and outgoing pions. Calculation for the special case of 450 MeV incident protons is carried out to demonstrate the success of our model and the A-dependence of the cross-section is found to agree rather well with experiment. It turns out that the pion production process is dominated by the pion absorption and the relative proportion of protons and neutrons inside the nucleus is a significant factor. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

We construct a model to explain the production of pions in the bombardment by protons of various nuclei and we use the model to calculate relative cross-sections for the process. The model assumes that the incident proton interacts with the target nucleons individually and that the proton-nucleon cross-section can be used as a free parameter. The model accounts for many important nuclear effects, some for the first time in explaining the A-dependence of the pion yield. The effects included are those due to proton and pion absorption, to the background nuclear potentials and to the struck-nucleon momentum and density distributions. We compute differential cross-sections in several special cases and compare them with experimental data at 450 MeV. Agreement is only moderate, but it is as good as any previously obtained and, unlike the earlier results, it does not depend on the assumption of an absorbing neutron blanket. Our agreement depends instead on the use of a modern nuclear radius and a reasonable treatment of pion absorption. In this respect our results confirm what earlier workers had assumed, that absorption is the dominant factor controlling the proton-nucleus production of pions. Also important is the proton-nucleon production rate, a reasonable value of which we assume. Potential effects are important because the basic production rate and pion absorption are both very energy dependent. The effects of struck-nucleon momentum and density distribution, as we calculate them, are small at the energy considered. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

In this thesis, a detailed study is made of the phenomenon of Octet Enhancement in hadronic interactions. After a survey of the experimental consequences of Octet Enhancement is made in Chapter II, a review and discussion of the various theories of Octet Enhancement is given in Chapter III. In Chapter IV, a general group theorectical discussion, based on an extension of Glashow's Method (S. L. Glashovr, 1963) of spontaneous symmetry breaking is presented. A general theorem in connection with spontaneous symmetry breaking is stated and proved. The theorem lends itself to a number of interesting applications. Among these is a demonstration that if a unitary triplet exists in nature which is non-trivially coupled to the rest of the hadrons, then Octet Enhancement follows without recourse to any detailed dynamical assumption. In particular, the triplet need not be quarks in the sense of fundamental building blocks of all matter. It is also demonstrated group theoretically that ϕ-ω mixing can in principle occur as a particular form of spontaneous symmetry breaking, in exactly the same way that a spontaneous mass splitting can occur. Assuming Octet Dominance in the symmetry breaking of a degenerate nonet of vector mesons, it follows quite generally that the formulae [formulae omitted] must hold. Here again, no dynamical detail is required. In Chapter V, a bootstrap model consisting of an octet of vector mesons is constructed with which it is demonstrated step by step how Octet Enhancement follows from the intricate working of two dynamical principles — (a) the bootstrap hypothesis and (b) that the mesons participating in the bootstrap must be physical particles and not ghost states. In Chapter VI, the model is extended to study ϕ-ω mixing. A phenomenon which can be interpreted as a "sponteneous" ϕ-ω mixing is found to in fact occur. Furthermore, formulae (i) and (ii) also emerge from this model. The only extra assumption besides (a) and (b) that we have to make here is the mere "existence" of a unitary singlet vector meson whose "bare" mass (the mass of the particle before it is embroiled in the bootstrap) is equal to average mass of the octet. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Approximate forms for the symmetric S- and D- state components of the triton wave functions are found using the equivalent two - body approximation of Feshbach and Rubinow. Two coupled, ordinary differential equations for the components are obtained and, for comparison with previous work, are solved numerically with the Feshbach - Pease two nucleon potentials. A further approximation involving one variational parameter is shown to yield good results. Detailed expressions for the symmetric S- and D-state contributions to the charge form factor of the triton are found and the symmetric S-state contribution is compared to the results of Schiff. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

In this thesis we calculate the symmetric S-state contribution to the binding energy of the triton (H³) using the nucleon-nucleon potentials recently developed by Wong (1965). Towards this end we employ a modification of the equivalent two-body method used by Peshbach-Rubinow (1955). / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A brief summary of observational data is presented, covering the disturbances recorded within seconds of high-altitude nuclear detonations, with particular emphasis on the "phase B" signal recorded at H+2 seconds following the "Starfish" test of July 9, 1962. The salient characteristics of this signal are specified, and a number of suggested models are analysed in detail. Although no conclusive decision can be reached on the basis of presently available data, the most likely mechanism appears to be hydromagnetic waves along the field line through the detonation point, with energy conversion into electromagnetic modes at the mirror points. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The differential cross sections for the production of definite lambda hypernuclear states, within the single scattering, impulse approximation, are calculated from the reaction n(K⁻,π⁻)Λ° on nuclear targets of helium, carbon and oxygen at various K-meson incident momentum. It is shown that these predictions are very sensitive to the three momentum transfer and to the wave function of the bound lambda in the hypernucleus. From the calculations, it is shown that it is possible to observe their production by studying the missing mass spectrum of the emitted pion. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A proton polarimeter employing multi-wire delay-line drift chambers (MWDDCs) has been built for ongoing pion absorption studies in the meson area at TRIUMF. A brief introduction of the theoretical basis of polarimeter and MWDCC operation is offered. An in-depth study of our own system is presented including an account of the data acquisition readout electronics and the procedures used for wire chamber position calibration. Detailed performance specifications of all aspects of our chamber are given, notably for the method used to solve the drift chamber left/right ambiguity. The chambers are found to operate reliably and efficiently with very good spatial resolution, σ = ~200µm. The systematic artificial asymmetry in the polarimeter is also studied. Finally, scattering-efficiency and figure-of-merit ([formula omitted]) results are presented for 230 MeV protons scattering off a 7cm carbon analyzer in the three cases of ø + π and 2π azimuthal scattering acceptance symmetry, and full polarimeter acceptance. In particular, it is found that when employing the Besset weighted-sums polarization extraction technique, imposition of ø + π azimuthal scattering symmetry results in only a small increase in measured statistical error compared to results obtainable from a full Fourier spectrum analysis with no applied acceptance symmetry. Suggestions for improvements to established practices are offered throughout. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The free neutron-proton elastic differential cross section has been measured at neutron beam energies of 212 and 418 MeV. . The experiment determined the angular distribution over the range 15°-180° (CM) in two segments, having the same overall normalization. The 15°-90° range was measured by detecting scattered neutrons in a scintillator and HWPC array. Normalization was obtained by moving the array into the direct neutron beam. Energy selection was made via a time of flight (TOF) measurement relative to the TRIUMF cyclotron RF. The neutron detector was calibrated absolutely using an associated particle technique, in which the recoil proton was detected. The ratio of coincidentally observed neutron-proton pairs to protons alone yielded the efficiency, which was used to calibrate neutron beam monitors. The remainder of the angular distribution was obtained by detecting the scattered protons in a magnetic spectrometer. Proton selection was made using the TOP through the spectrometer and the momentum. Energy selection was made via the BF TOF. Normalization was provided by the same monitors as used in the measurement of the forward half of the angular distribution. The normalization of d?/dΩ has been determined to about 3%, with statistical accuracies of about 1-3% on the individual data points. These data have been included in a phase shift analysis together with all world data, showing an improvement in the energy dependence of the differential cross section near 0° CM and in the phase shifts, notably, E₃. Together with the previously measured Wolfenstein parameters, unambiguous phase shifts in the I=0 system are obtained for the first time in the TRIUMF energy range. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A separable potential model is constructed to describe the coupled ΣN-AN systems. From this the Σ single particle potential is developed including Pauli effects. The momentum space Schroedinger equation is then solved self-consistently for the complex eigenvalues of 1s and lp state Σ° hypernuclei. Arising from two quite distinct mechanisms these states are all found to be long lived. In s-states, Pauli suppression of the ΣN->AN conversion reduces the widths by as much as 50% from classical estimates in heavy nuclei, and in light nuclei produces widths as small as 1.8 MeV inΣ[sub=o;sup=5]He. In p-states, Pauli effects are relatively unimportant and the strong absorption of the potential creates extremely narrow quasi-bound states in the Σ continuum. / Science, Faculty of / Physics and Astronomy, Department of / Graduate