Chiral symmetry and light resonances in hot and dense matter

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 whe...

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Bibliographic Details
Authors: Cabrera, Daniel, Fernández Fraile, Daniel, Gómez Nicola, Ángel
Format: article
Publication Date:2009
Country:España
Institution:Universidad Complutense de Madrid (UCM)
Repository:Docta Complutense
Language:English
OAI Identifier:oai:docta.ucm.es:20.500.14352/44578
Online Access:https://hdl.handle.net/20.500.14352/44578
Access Level:Open access
Keyword:51-73
Pi-pi interaction
Qcd sum-rules
Perturbation-theory
Nuclear-matter
Rho-meson
Finite-temperature
Nonperturbative approach
Effective lagrangians
Vector-mesons
One-loop
Física-Modelos matemáticos
Física matemática
Description
Summary: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.