The importance of the measurement of ϱ for the understanding of high energy hadron-hadron scattering

Abstract

We first show, both on general and phenomenological grounds, why the most suitable parameter for exploring odderon effects in the present energy range is the ϱ-parameter (the ratio of the real over the imaginary part of the forward hadron amplitude). We perform an almost model-independent analysis of the experimental data by taking into account the analyticity constraints and the assumption og maximality. Using the maximal odderon approach as a guide, we establish the following very constrained bound at √s=546 GeV: ϱ pp ≲0.23 . Our bound leads to the conclusion that an experimental UA4/2 value centred around 0.20, say 0.20±0.02, will constitute a strong and unambiguous signal of odderon effects and will indicate that at high energy σ T pp > σ T p p .