THE EFFECTIVE-MASS AND SCREENING MASS OF THE RHO-MESON FOR THE VECTORDOMINANCE MODEL AND THE VECTOR COUPLING MODEL AT FINITE-TEMPERATURE AND DENSITY

In the framework of thermo-field dynamics, the temperature and/or dens ity dependences of the effective mass and the screening mass of the rh o-meson for the vector dominance model and the nucleon-nucleon-rho-mes on (NN rho) vector coupling model have been calculated. We have found that for the vector dominance model, the effective mass and the screen ing mass of the rho-meson increase with temperature, and for the NN rh o vector coupling model, they remain almost unchanged with temperature , but increase with density.