CONSTRAINTS ON THE RELATIVISTIC MEAN-FIELD OF DELTA-ISOBAR IN NUCLEAR-MATTER

The effects of the presence of Delta-isobars in nuclear matter are stu died in the framework of relativistic mean-field theory. The existence of stable nuclei at saturation density imposes constraints on the Del ta-isobar self-energy and thereby on the mean-field coupling constants of the scalar and vector mesons with Delta-isobars. The range of poss ible values for the scalar and vector coupling constants of Delta-isob ars with respect to the nucleon coupling is investigated and compared to recent predictions of QCD sum-rule calculations. (C) 1998 Elsevier Science B.V.