RT Book, Section T1 Precise determination of the σ pole location from a dispersive analysis A1 Garcia Martin, R. A1 Kamiński, Robert A1 Peláez Sagredo, José Ramón AB We review how the use of recent precise data on kaon decays together with forward dispersion relations (FDR) and Roy’s equations allow us to determine the σ resonance pole position very precisely, by using only experimental input. In addition, we present preliminary results for a modified set of Roy-like equations with only one subtraction, that showaremarkable improvement in the precision around the σ region. For practical applications, these results are shown to be very well approximated by a very simple conformal expansion PB Amer Inst Physics SN 978-0-7354-0554-7 YR 2008 FD 2008 LK https://hdl.handle.net/20.500.14352/53482 UL https://hdl.handle.net/20.500.14352/53482 LA eng NO ISSN: 0094-243X©Amer Inst Physics.Workshop on Scalar Mesons and Related Topics (2008. Lisboa, Portugal).We thank Prof. F. J. Ynduráin for his comments and suggestions, the organizers for creating the nice scientific atmosphere of the workshop and the Spanish research contracts PR27/05-13955-BSCH, FPA2004-02602, UCM-CAM 910309 and BFM2003-00856 for partial financial support. DS Docta Complutense RD 7 abr 2025