Spectral Function Of Rho Meson In Hot And Dense Pion Medium

The study of the hadronic property under extreme environment is paid much attention in theoretical nuclear physics. It plays an important role in high energy heavy ion collision experiments and astrophysics. Medium effect is an important respect in the study of hot dense hadronic property. The hadronic property, say mass and width, could be changed by the medium effect, and such influence can be reflected from the spectral function. This thesis focuses on the spectral function of rho meson in hot and dense pion medium.Finite temperature field theory is a fundamental theory established to study physical system in hot/dense environment. It contains two totally different theoretical frames as we called imaginary-time formalism and real-time formalism both of which have been illustrated in this thesis. Our discussion is based on imaginary-time formalism. The deduction of the spectral function is also performed in this thesis.Rho meson gets quite much attention and is expected to carry information about the central fireball formed in the heavy ion collision, because its lifetime is shorter than that of the fireball. Meanwhile, pion also achieved highly concentrations for it has been largely produced in high energy heavy collisions recently. Based on imaginary-time finite temperature field theory, the effects of hot and dense pion environment on the spectral function of rho meson is analyzed within an effective model that describes the p — π coupling. The results from numerical calculation show that the spectral function becomes wider and the peak moves towards the high invariant mass region when the temperature and the pion chemical potential increase.