DENSITY ISOMERS OR DELTA-MATTER

We demonstrate that the appearance of the density isomers depends on t he meson-nucleon coupling strengths in addition to the meson-delta cou pling strengths within the mean field theory. Furthermore, the in-medi um NN --> N Delta cross section is studied with different values of th e coupling strengths for deltas. We have found that the in-medium NN - -> N Delta cross section substantially increases with the increasing o f scalar meson-delta coupling strength even for the case when the dens ity isomers do not appear within the mean field theory, which shows th e possibility of creating Delta-matter in energetic heavy-ion collisio ns.