Prof John Cardy FRS

Abstract:

We show that, contrary to previous assertions, multi-pomeron couplings to the external particles are equally as important as single couplings in the asymptotic behaviour of the amplitude in the reggeon calculus. Our arguments require a careful discussion of the relation of the reggeon calculus to a renormalizable field theory and of the renormalization of composite operators in reggeon field theory. © 1978.

Abstract:

We estimate the behaviour of the perturbation expansion and the ε{lunate} expansion at large orders in reggeon field theory. The perturbation expansion is divergent but Borel summable for α0 < 1. At fixed total rapidity, the Borel summability extends into α0 > 1. © 1977.

Abstract:

By using the method of Lipatov to determine the behavior of perturbation theory at large order, we derive a convergent numerical procedure for the calculation of the critical exponents of Reggeon field theory, based on the loop expansion and the ε{lunate} expansion. We find the results γ = -0.26 ± 0.02, z = 1.13 ± 0.01 and λ = 0.49 ±0.01. © 1977.