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UBC Theses and Dissertations

Octet enchancement in hadronic interactions Chan, Choi-Lai


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.

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