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S. T. Tsou

Publications and source records attributed to S. T. Tsou.

26 records · Page 2Linked to original sources

Fermion transmutation - a renormalization effect in gauge theory

A new category of phenomena is predicted in which fermions of different flavours can transmute into one another, for example $e \to μ$ or $e \to τ$, as a consequence of the `rotating' mass matrix due to renormalization. As examples, calculations will be presented for various such processes. Some of these could be accessible to experiments in the near future.

hep-ph↗

Concepts in Gauge Theory Leading to Electric--Magnetic Duality

Gauge theory, which is the basis of all particle physics, is itself based on a few fundamental concepts, the consequences of which are often as beautiful as they are deep. In this short lecture course I shall try to give an introduction to these concepts, both from the physical and mathematical points of view. Then I shall show how these considerations lead to a nonabelian generalization of the well-known electric--magnetic duality in electromagnetism. I shall end by sketching some of the many consequences in quantum field theory that this duality engenders in particle physics. These are notes from a lecture course given in the Summer School on {\em Geometric Methods in Quantum Field Theory}, Villa de Leyva, Colombia, July 1999, as well as a series of graduate lectures given in Oxford in Trinity Term of 1999 and 2000.

hep-th↗

Geometry of the non-Abelian 2-index potential and twisted de Rham cohomology

It is found that the 2-index potential in nonabelian theories does not behave geometrically as a connection but that, considered as an element of the second de Rham cohomology group twisted by a flat connection, it fits well with all the properties assigned to it in various physical contexts. We also prove some results on the Euler characteristic of the twisted de Rham complex. Finally, provided that some conditions are satisfied, we propose a non-Abelian generalisation of S-duality.

hep-th↗

Flavour-Changing Neutral Currents in the Dualized Standard Model

The Dualized Standard Model which gives explanations for both fermion generations and Higgs fields has already been used to calculate fermion mass and mixing parameters with success. In this paper, we extend its application to low energy FCNC effects deriving bounds for various processes in terms of one single mass scale. Using then experimental information from K_L - K_S mass difference and air showers beyond the GZK cut-off, these bounds are converted into rough, order-of-magnitude predictions. In particular, the estimates for the decay K_L \to e^\pm μ^\mp and for the mass difference between the neutral D-mesons seem accessible to experiment in the near future.

hep-ph↗

Possible Explanation for $E > 10^{20}$ eV Air Showers with Flavour-Changing Neutral Currents

Air showers observed with $E > 10^{20}$ eV pose a problem since protons at such energies cannot survive a long journey through the 2.7 K microwave background. It is suggested that they are initiated instead by neutrinos which become strongly interacting through exchanges of gauge bosons associated with generation-changing neutral currents, a suggestion which is supported by calculations in a dualized standard model recently proposed. In turn, the suggestion bounds the mass of the gauge bosons and gives estimates for the branching ratios of FCNC s, c, b, and t meson decays which are accessible to experiments now being planned.

hep-ph↗

Geometric interpretation of the 2-index potential as twisted de Rham cohomology

It is found that the 2-index potential in nonabelian theories does not behave geometrically as a connection but that, considered as an element of the second de Rham cohomology group twisted by a flat connection, it fits well with all the properties assigned to it in various physical contexts. We also prove some results on the Euler characteristic of the twisted de Rham complex.

hep-th↗

't Hooft's Order-Disorder Parameters and the Dual Potential

It is shown that the operator $B(C) = Tr [P \exp i \tilde{g} \oint \tilde{A}_i(x) dx^i]$ constructed with the recently derived dual potential $\tilde{A}(x)$ and a coupling $\tilde{g}$ related to $g$ by the Dirac quantization condition satisfies the correct commutation relation with the Wilson operator $Tr [P \exp ig \oint A_i(x) dx^i]$ as required by 't Hooft for his order-disorder parameters.

hep-th↗

Physical Consequences of Nonabelian Duality in the Standard Model

Possible physical consequences of a recently discovered nonabelian dual symmetry are explored in the standard model. It is found that both Higgs fields and fermion generations can be assigned a natural place in the dual framework, with Higgs fields appearing as frames (or `N-beins') in internal symmetry space, and generations appearing as spontaneously broken dual colour. Fermions then occur in exactly 3 generations and have a factorizable mass matrix which gives automatically one generation much heavier than the other two. The CKM matrix is the identity at zeroth order, but acquires mixing through higher loop corrections. Preliminary considerations are given to calculating the CKM matrix and lower generation masses. New vector and Higgs bosons are predicted.

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