RT Book, Section T1 Recent progress on the light meson resonance description from unitarized chiral perturbation theory and large N_c A1 Peláez Sagredo, José Ramón AB We present a brief account of the developments in the description of light meson resonances using unitarized extensions of the Chiral Perturbation Theory series, both in energy and temperature. In particular, we describe how these methods have been recently shown to describe simultaneously the low energy and resonance regions of meson-meson scattering. This approach could be of relevance to understand the light scalar mesons since it provides a formalism that respects chiral symmetry and unitarity and is able to generate resonant states without any a priori theoretical bias toward their existence, classification or spectroscopic nature. We will also review how this approach is also able to describe the thermal evolution of the p and a mesons. In addition we review their extensions to higher orders, the most recent determination of the resonance pole properties, as well as their behavior in the large N_c limit, which could be of relevance to understand their spectroscopic nature. PB Amer Inst Physics SN 0-7354-0159-4 YR 2003 FD 2003 LK https://hdl.handle.net/20.500.14352/60962 UL https://hdl.handle.net/20.500.14352/60962 LA eng NO ©Amer Inst Physics.High Energy Physics Workshop on Scalar Mesons - An Interesting Puzzle for QCD. (2003. Utica, Nueva York)First of all, I wish to thank the workshop organizers, specially A. Fariborz, for their kind invitation and for their efforts to offer us such a nice atmosphere in Utica. I also wish to thank my collaborators A. Dobado, F. J. Llanes-Estrada and specially A. Gómez Nicola for his comments and his careful reading of the manuscript. I also thank A. Andrianov, D. Espriu, R. Jaffe, F. Kleefeld, M. Uehara and E. van Beveren for their encouragement and interesting discussions . Work supported by a Marie Curie fellowship, contract MCFI- 2001-01155, the Spanish CICYT projects, FPA2000-0956, PB98-0782 and BFM2000-1326, the CICYT-INFN collaboration grant 003P 640.15, and the E.U. EURIDICE network contract no. HPRN-CT-2002-00311. NO Marie Curie fellowship NO Spanish CICYT NO CICYT-INFN NO E.U. EURIDICE network DS Docta Complutense RD 6 abr 2025