Nuclear Incompressibility and the Asymmetry Term: Implications for Astrophysics and Physics with Exotic Nuclei

Abstract

The compressional‐mode giant resonances, the isoscalar giant monopole resonance (GMR) and the isoscalar giant dipole resonance (ISGDR), in various isotopes have been investigated using inelastic scattering of 400‐MeV α‐particles at extremely forward angles, including 0°. Recently, the centroid energies of the giant monopole resonance (GMR) in the Sn isotope region are found to be significantly lower than the theoretical predictions. In addition, based on the GMR results, the asymmetry‐term in the nuclear incompressibility has been determined as Kτ = −550±100 MeV. Constraints on interactions employed in nuclear structure calculations are discussed on the basis of the experimentally values for K∞ and Kτ. The combination of these two values gives stringent constraints on the interactions used for nuclear structure calculations and for formations of equation of state (EOS) of nuclear matter. A short review of the current status of the experimental studies on the compressional‐mode giant resonances is given, and a possible new experiment for astrophysics and physics with exotic nuclei is suggested.