Ruiz De Elvira Carrascal, JacoboGarcia Martin, R.Kamiński, RobertPeláez Sagredo, José Ramón2023-06-202023-06-202011978-0-7354-0899-910.1063/1.3575010https://hdl.handle.net/20.500.14352/45619ISSN: 0094-243X ©2011 American Institute of Physics 978-0-7354-0899-9. International Conference on Quark Confinement and the Hadron spectrum (QCHS IX) (9. 2010. Madrid). Work supported by Spanish Ministerio de Educación y Ciencia contracts: FPA2008-00592, FIS2008-01323 and U.Complutense/Banco Santander grant GR58/08 910309. We acknowledge support from the European Community-Research Infrastructure Integrating Activity Study of Strongly InteractingMatter (HadronPhysics2, Grant n. 227431) under the EU 7th Framework Programme. JRE acknowledges an Early Stage Researcher position supported by the EU-RTN Programme, Contract No. MRTN–CT-2006-035482, “Flavianet”.We show how the new precise data on kaon decays together with forward dispersion relations, sum rules and once- and twice-subtracted Roy equations allow for a precise analysis of π π scattering. The once subtracted Roy equations provide a more stringent consistency check for the parametrizations of the S0- wave data in the region from 450 to 1100 MeV that allows us to present a preliminary determination of the f_0(600) and f_0(980) poles from the constrained dispersive data analysis.engbook parthttp://dx.doi.org/10.1063/1.3575010http://scitation.aip.orgopen access51-73EquatiionFísica-Modelos matemáticosFísica matemática