RHO-MESON SELF-ENERGY AND DIELECTRON EMISSIVITY IN AN ISOSPIN-ASYMMETRIC PION MEDIUM

The rho-meson self-energy in an isospin-asymmetric pion gas at finite temperature and charged-pion chemical potential is evaluated. We utili ze a conventional effective pi-rho Lagrangian and the functional integ ral representation of the partition function in the second order in th e rho pi pi coupling constant. We analyze the rho-meson polarization o perator and its dependence on the invariant mass M and spatial momentu m \p\ of the rho meson. The pole positions and the values of the imagi nary parts of the self-energy for different polarization states have d ifferent functional dependences on M and \p\. The corresponding dielec tron rate (calculated from the imaginary part of the in-medium rho-mes on propagator) shows a distinctive asymmetry when the momentum = p(+) -p(-) is perpendicular or parallel to p, where p(+) are the e(+/-) mom enta of the electron pair.