The complete O(ɛ 2) reggeon field theory scaling law dσ el/d t and its applications at collider energies

Abstract

We give the complete asymptotic reggeon field theory (RFT) scaling law for the elastic cross section in O(ɛ 2), extending previous results to include the 3-pomeron cut. This provides the most detailed realistic test of this theory. Numerically we find the encouraging result that the small- t SPS collider data for dσ el/d t are in agreement with these new asymptotic RFT predictions. However, ISR data are not compatible with this theory, either in s or t dependence. Previous positive ISR results were largely due to the existence of a j = 1 fixed cut which is not present here. Our results, coupled with the observation that critical RFT fits to σ tot require large non-leading terms, imply that a lower bound for the RFT asymptotic scale in single renormalized propagator processes (σ tot,dσ el/d t) lies around SPS-collider energies. The asymptotic scale for multi-propagator processes (the rapidity plateau, ab→aX reactions, multiplicity distributions etc.) is expected to be well beyond the SPS collider. A possible global RFT picture is them that perturbation theory (including finite rapidity scale effects due to the excitation of new quantum numbers) is applicable through ISR and up to the SPS collider, consistent with recent observations. The critical RFT can become the relevant diffractive theory for σ tot and dσ el/d t at larger t at and above the SPS collider. Predictions for dσ el/d t at larger t at the SPS collider are given in this paper and we urge experimentalists to test them.