The deuteron asymptotic D-state as a probe of the nucleon-nucleon force

A critical discussion is given of the various contributions to the asymptotic D/S ratio from the πNN interaction. Particular emphasis is laid on the analysis of contributions from 2π exchange, the dependence on the πNN form factor, and on the πN coupling constant, so as to assess quantitatively the model dependence of the result. From this analysis, significant restrictions are deduced on the shape of the πNN form factor and, in quark bag models, the value of the quark bag radius. The results of previous theoretical approaches for the D/S ratio and quadrupole moment are shown to obey a universal and linear relation, when expressed in reduced units so as to compensate for small differences in effective range and πN coupling constant. The quadrupole moment is also quantitatively analyzed in detail. Its value is proved to be an accurate and almost model-independent consequence of the experimental D/S ratio (apart from relativistic and meson-exchange corrections) in agreement with observations. In the comparison with experiments, a critical survey of the relevant experimental data is given. In particular, a considerably improved value for the quadrupole moment is deduced.