Spin structure of high-energy multiple scattering

Abstract

A multichannel K-matrix formalism is used to unitarize the amplitudes for elastic scattering and diffraction dissociation written down in the impact-parameter representation. The inelastic intermediate states in the unitarity relations are effectively represented by a set of quasi-two-particle states. The complications due to nonvanishing spins are considered and the constraints resulting from definite (natural or unnatural) parity in the s- and t-channel are investigated. It is found that the Pomeranchuk contribution can be built up from multiple exchanges of lower lying trajectories. The Pomeranchuk coupling in helicity flip transitions turns out in this model to be logarithmically suppressed with increasing energy compared to the corresponding helicity nonflip couplings of the “vacuum trajectory”. The coupling determining the imaginary parts of the helicity nonflip elastic scattering and diffraction dissociation amplitudes is found to correspond to natural parity exchanged in the t-channel only. Contrary to this the real parts of the amplitudes for helicity nonflip elastic scattering and diffraction dissociation receive in this model at large energies contributions from both natural and unnatural parity exchange in the t-channel. The same is true for the Pomeranchuk contributions to helicity flip elastic scattering and diffraction dissociation processes which are, already in lowest order rescattering, determined by a mixture of natural and unnatural parity exchanged in the t-channel.