Quark substructure and isobar effects on deuteron form-factors

Abstract

The R-matrix boundary condition method provides a hybrid quark/gluon and hadron model. Elastic ed scattering, with deuteron polarization, up to high momentum transfer provides detailed information on the deuteron wave function. This determines the rangedependence of the orbital and spin components of the one- and two-body currents, restricting contributions of isobar and meson-exchange currents and of quark/gluon degrees of freedom, as well as the nucleon component. The R-matrix boundary condition model combines all these effects, predicting nucleon-nucleon (NN) reactions and the deuteron form factors simultaneously. A few of the parameters are not predetermined by data independent of the NN interaction and symmetry requirements. The remaining few are almost all determined by NN scattering data. Following a review of the R-matrix method and its application to the NN system, three specific models of different levels of completeness are compared with the NN scattering and electron-deuteron form-factors data. From these one can extrapolate to a model that represents all the data.