Modifications of the rho-meson from the virtual pion cloud in hot and dense matter

Citation
M. Urban et al., Modifications of the rho-meson from the virtual pion cloud in hot and dense matter, NUCL PHYS A, 673(1-4), 2000, pp. 357-374
Citations number
27
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
NUCLEAR PHYSICS A
ISSN journal
0375-9474 → ACNP
Volume
673
Issue
1-4
Year of publication
2000
Pages
357 - 374
Database
ISI
SICI code
0375-9474(20000619)673:1-4<357:MOTRFT>2.0.ZU;2-I
Abstract
The modification of the rho-meson self-energy due to the coupling to in-med ium pions is calculated consistently at finite baryon density and temperatu re, keeping the full 3-momentum dependence in a gauge invariant way. As a f unction of nucleon density, the rho-meson spectral function is strongly enh anced in the invariant mass region M less than or similar to 650 MeV, while the maximum, i.e., the pole mass, is slightly shifted upwards. As a functi on of temperature, for fixed nucleon density, the imaginary part of the sel f-energy increases further due to Bose-enhancement. At the same time the ma ss shift from the real part becomes very large. As a consequence of these m edium effects, the dilepton rate in the low-mass region M less than or simi lar to 650 MeV increases strongly, while the peak at M approximate to 770 M eV disappears. (C) 2000 Elsevier Science B.V. All rights reserved.