Cabrera, DanielFernández Fraile, DanielGómez Nicola, Ángel2023-06-202023-06-202009-061434-604410.1140/epjc/s10052-008-0831-zhttps://hdl.handle.net/20.500.14352/44578© Springer-Verlag / Società Italiana di Fisica 2008. International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions (3. 2008. Isla de La Toja, España). We acknowledge financial support from Spanish research projects FPA2004-02602, FPA2005-02327, PR34/07-1856-BSCH, UCM-CAM 910309/08, FPA2007-29115-E and from the F.P.I. Programme (BES-2005-6726). D.C. wishes to thank support from the “Juan de la Cierva” Programme (Ministerio de Educación y Ciencia, Spain)We present a study of the pi pi scattering amplitude in the sigma and rho channels at finite temperature and nuclear density within a chiral unitary framework. Meson resonances are dynamically generated in our approach, which allows us to analyze the behavior of their associated scattering poles when the system is driven towards chiral-symmetry restoration. Medium effects are incorporated in three ways: (a) by thermal corrections of the unitarized scattering amplitudes, (b) by finite nuclear-density effects associated to a renormalization of the pion decay constant, and complementarily (c) by extending our calculation of the scalar-isoscalar channel to account for finite nuclear-density and temperature effects in a microscopic many-body implementation of pion dynamics. Our results are discussed in connection with several phenomenological aspects relevant for nuclear-matter and heavy-ion collision experiments, such as rho mass scaling versus broadening from dilepton spectra and chiral restoration signals in the sigma channel. We also elaborate on the molecular nature of pi pi resonances.engjournal articlehttp://dx.doi.org/10.1140/epjc/s10052-008-0831-zhttp://link.springer.comopen access51-73Pi-pi interactionQcd sum-rulesPerturbation-theoryNuclear-matterRho-mesonFinite-temperatureNonperturbative approachEffective lagrangiansVector-mesonsOne-loopFísica-Modelos matemáticosFísica matemática