Off-Shell NN Potential and Nuclear Binding

Abstract

A new, high-precision, charge-dependent Bonn nucleon-nucleon potential (‘CD-Bonn’) has been constructed that is exactly phase-equivalent to the Nijmegen phase shift analysis and the new high-quality Nijmegen potentials. This non-local CD-Bonn potential predicts 8.0 MeV binding energy for the triton (in a charge-dependent 34-channel Faddeev calculation) which is about 0.4 MeV more than the predictions by the local (phase-equivalent) Nijmegen potential. We pin down origin and size of the nonlocality in the Bonn potential, in analytic and numeric form. The nonlocality is due to the use of the correct relativistic off-shell Feynman amplitude of one-boson-exchange avoiding the commonly used on-shell approximations which yield the local potentials. Adding the relativistic effects from the relativistic nucleon propagators in the Faddeev equations, brings the CD-Bonn result up to 8.2 MeV triton binding. This leaves a difference of only about 0.3 MeV to experiment, which may possibly be explained by refinements in the treatment of relativity and the inclusion of other nonlocalities (e. g., those due to the composite nature of hadrons). Nuclear matter calculations further illustrate our points.