Modifications of the rho-meson from the virtual pion cloud in hot and dense matter
✍ Scribed by M. Urban; M. Buballa; R. Rapp; J. Wambach
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 229 KB
- Volume
- 673
- Category
- Article
- ISSN
- 0375-9474
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✦ Synopsis
The modification of the ρ-meson self-energy due to the coupling to in-medium pions is calculated consistently at finite baryon density and temperature, keeping the full 3-momentum dependence in a gauge invariant way. As a function of nucleon density, the ρ-meson spectral function is strongly enhanced in the invariant mass region M 650 MeV, while the maximum, i.e., the pole mass, is slightly shifted upwards. As a function of temperature, for fixed nucleon density, the imaginary part of the self-energy increases further due to Bose-enhancement. At the same time the mass shift from the real part becomes very large. As a consequence of these medium effects, the dilepton rate in the low-mass region M 650 MeV increases strongly, while the peak at M ≈ 770 MeV disappears.