Chiral Symmetry and light resonances in hot and dense matter

Abstract

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 vs broadening from dilepton spectra and chiral restoration signals in the $\sigma$ channel. We also elaborate on the molecular nature of $\pi \pi$ resonances.

14 pages, 14 figures. Contribution to Hard Probes 2008, Illa de A Toxa, Spain, June 8th-14th 2008

References in corpus (4)

• Quark mass dependence of the rho and sigma from dispersion relations and Chiral Perturbation Theory
• The Inverse Amplitude Method and Adler Zeros
• Pion scattering poles and chiral symmetry restoration
• Thermal Dilepton Production from Dropping rho based on the Vector Manifestation

Cited by in corpus (4)

• Scalar susceptibilities and four-quark condensates in the meson gas within Chiral Perturbation Theory
• Nature of the sigma meson as revealed by its softening process
• The pion-kaon scattering amplitude and the $K^0(700)$ and $K^{\ast }(892)$ resonances at finite temperature
• Review on recent progress in the study of the $N^{\ast }(920)$ subthreshold singularity and the $\sigma /f_0(500)$ meson