Off-Shell Effects in Nuclear Matter

We examine the binding energy of nuclear matter for exactly phase-shift-equivalent potentials. We generate these potentials by applying a short-range unitary transformation to the Reid soft-core potential. All potentials have a one-pion-exchange tail. We find that, for the potentials studied, variations of up to 9.5 MeV in the binding energy and 0.33 F^-1 in the saturation density occur. The variations in binding energy are linearly correlated with the wound integral κ for those potentials that give nearly the same deuteron electric form factor. An increase in κ leads to less binding in nuclear matter. The sensitivity of the binding energy is somewhat greater to the ³S₁+³D₁ contribution to κ than to the ¹S₀ contribution to κ. We give a theoretical explanation, based on the modified Moszkowski-Scott separation approximation, to account for the sensitivity of the binding energy to the ¹S₀ and ³S₁+³D₁ contributions to κ. We also discuss the relation of κ and the binding energy of nuclear matter to the off-shell elements of the T matrix. We discover that far-off-shell elements (q6 F^-1) play a significant role in nuclear matter.