Summary: | The work contained in Part I of this thesis is clearly divided into three distinct sections, each of which deals with a separate aspect of the subject. In Chapter 1, the elastic electromagnetic scattering of two spin 1/2 particles is discussed in the one—photon—exchange approximation, allowing for the possibility of structure of both fermions by means of form factors. Covariant notation is employed throughout, and the algebraic form of the resulting formulae leads naturaly to the use of certain combinations of the Dirac and Pauli form factors rather than these functions themselves. These new 'electric' and 'magnetic' form factors are discussed in detail, and adapted for use in all subsequent work. The formalism is then applied to a discussion of the scattering of muons by protons, and the annihilation of proton—antiproton pairs into lepton pairs; with particular reference to the possibility of detecting a structure of the muon. In Chapter 2, the second order electromagnetic corrections to the above processes are discussed in the framework of an effective perturbation theoretic treatment of the exchange of resonances in the two—photon channel. The possibility of detecting such effects in the process of electron—proton scattering is then considered in this formalism. Chapter 3 contains a calculation of the isovector nucleon form factors by means of unsubtracted dispersion relations. The method of Singh and Udgaonkar is applied to the new form factors with the pleasing result that reasonable figures are obtained for the static values of both the electric and magnetic form factors simultaneously. Part II of the thesis is an investigation of the possibility of using a second rank tensor field to describe a relativistic local spin-2 field. The difficulties involved are discussed in detail, and, in the absence of a complete solution of the problem, a non-local theory is developed for use in Chapter 2 of part I of this thesis.
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