Nuclear theory group progress report and renewal proposal, December 1, 1981-November 30, 1984

The work of the Stony Brook Nuclear Theory Group covers a broad range of topics in theoretical nuclear structure. Primary emphasis is placed on understanding the origin of the nucleon-nucleon and meson-nucleon interactions. Phenomenological treatments of QCD, using chiral invariance as a guide, are central to our efforts here; through the chiral bag model they give us also an improved understanding of the structure of hadrons. Starting from the free interaction, many-body techniques have been used to construct the effective interaction between nucleons in nuclei. Analysis of a wide range of nuclear phenomena has been carried out using such effective interactions. Among the most interesting are nuclear giant resonances for which we offer a dynamical theory of nuclear vibrations which emphasizes the energy dependence of the effective interaction. Continuing our earlier description of the collapse of large stars, we have worked out the formation of the shock wave upon bounce, and its progress out through the star. We believe this shock wave to blow off the mantle and envelope of the star, leaving a compact remnant, the pulsar. Computer calculations follow this scenario until the shock is some distance beyond the neutrino sphere, where the shock then runs out of energy. We are extending these calculations to a description of explosive nucleosynthesis. We have also been studying heavy ion reactions. In the low-energy regime, we have concentrated on nuclear quasimolecular states, and on the angular dependence of deep inelastic scattering. In the relativistic regime, we wish to extend our old work on states of dense matter