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

Abstract

We review our recent analysis of pion-pion scattering data in terms of Roy equations and Forward Dispersion Relations, and present some preliminary results in terms of a new set of once-subtracted coupled equations for partial waves. The first analysis consists of independent fits to the different pion-pion 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.

Comments: 6 pages, two figures. To appear in the proceedings of the Workshop on Scalar Mesons and Related Topics, Lisbon, Portugal, 11-16 Feb 2008