Peláez Sagredo, José RamónGarcia Martin, R.Kamiński, RobertYnduráin, F. J.2023-06-202023-06-202008978-0-7354-0899-910.1063/1.2973509https://hdl.handle.net/20.500.14352/53481ISSN: 0094-243X ©2008 American Institute of Physics. Workshop on Scalar Mesons and Related Topics (2008. Lisboa, Portugal). J.R.P. thanks the organizers for creating such a stimulating conference.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.engbook parthttp://dx.doi.org/10.1063/1.2973509http://scitation.aip.orgopen access538.9Phase-shiftsFísica del estado sólidoFísica matemática2211 Física del Estado Sólido