Nucleon-nucleon correlations and the Coulomb Displacement Energy

Abstract

Coulomb Displacement Energies (CDE) are accurately known for a wide range of nuclear masses. Assuming isospin independence in the nuclear Hamiltonian, the CDE can in first instance be interpreted as the Coulomb interaction energy between the density of the excess neutrons and the proton charge density in the parent nucleus. However, when using reasonable meanfield models for the proton and neutron density one underestimates the CDE by about 8% on average. This discrepancy is known as the Nolen-Shiffer anomaly, and various explanations have been put forward in the past. In this work we reexamine the role of nucleon-nucleon correlations. We present calculations for the pair density functions in various nuclei. Preliminary results suggest that the modifications to the mean-field pair density functions cause an enhancement of the CDE in the order of 4%, which is ratherA-independent.