Precise analysis of π π scattering data from Roy equations and forward dispersion relations

Abstract

We review our recent analysis of ππ scattering data in terms of Roy equations and Forward Dispersion Relations, and present some preliminary results in terms of a new set of oncesubtracted coupled equations for partial waves. The first analysis consists of independent fits to the different ππ channels that satisfies rather well the dispersive representation. In the second analysis we constrain the fit with the dispersion relations. The latter provides a very precise and model independent description of data using just analyticity, causality and crossing.