Prof John Cardy FRS

Abstract:

A reggeon calculus is derived from a hybrid perturbation-theory model using eikonal techniques. The resulting reggeon coupling functions have a simple form which enables many diagrams of interest to be evaluated explicitly. As an example, the properties of iterated Regge cuts are discussed and evaluated. Another important result is that the physical pomeron is not expected to have factorisable residues. © 1969.

Abstract:

The eikonal approximation is extended to arbitrary Feynman diagrams, in a renormalised spinless theory. A set of rules is formulated, which gives the eikonal expression for any given set of diagrams. Features reminiscent of a parton model emerge. © 1969.

Abstract:

A study is made of the high-energy behaviour of the elastic two-particle amplitude at fixed scattering angle, in both a simple س model, and in quantum electrodynamics. In the first case, diagrams associated with the Born terms are shown to dominate. In the second, electron-electron scattering is shown to exhibit a power-law dependence on the energy, more rapidly decreasing than that of the Born terms alone. © 1969.