Smooth nucleon–nucleon interactions and meson theory

Tabakin and Davies have shown that it is possible to fit the singlet-state nucleon–nucleon data with a potential that is smooth enough to give very small second-order terms in an ordinary perturbation–theoretic treatment of nuclear matter. However, their potential is unrealistic in that the requirements of meson theory are in no way satisfied in the long-range region. It is shown here that a potential whose long-range part conforms to the OBEP of Bryan and Scott can still be made to fit the phase shifts without increasing significantly the second-order terms. Thus, with meson theory being incapable of making an unequivocal statement about the short-range region, it will only be by resorting to the experimental evidence for short-range correlations in nuclei that one will be able to resolve the question as to whether or not an interaction as smooth as the one considered here can be regarded as "real" rather than merely "effective". In any event, the existence of such correlations cannot be inferred from the singlet nucleon–nucleon data.