Photonuclear sum rules and interaction effects in the deuteron

Abstract

The photonuclear sum rules σ o , σ −1, and σ −2 are evaluated for the deuteron by direct integration of the theoretical cross section up to the π-threshold. Effects of isobar configurations and mesonexchange currents are included. The integrated cross section is also determined from the double commutator of the dipole operator with the Hamiltonian. The usual potentials increase the classical sum rule σ 0 by about 50 % while isobar configurations contribute an additional 20 % which is in reasonable agreement with the experimental integrated cross section above the Δ-resonance up to 540 MeV. The energy weighted sum rules σ −1 and σ −2 are little affected by interaction effects. Electric polarizability and paramagnetic susceptibility are also calculated.