NNcore interactions and differential cross sections from one gluon exchange

We derive nonstrange baryon-baryon scattering amplitudes in the nonrelativistic quark model using the ``quark Born diagram'' formalism. This approach describes the scattering as a single interaction, here the one-gluon-exchange (OGE) spin-spin term followed by constituent interchange, with external nonrelativistic baryon wave functions attached to the scattering diagrams to incorporate higher-twist wave-function effects. The short-range repulsive core in the NN interaction has previously been attributed to this spin-spin interaction in the literature; we find that these perturbative constituent-interchange diagrams do indeed predict repulsive interactions in all I,S channels of the nucleon-nucleon system, and we compare our results for the equivalent short-range potentials to the core potentials found by other authors using nonperturbative methods. We also apply our perturbative techniques to the N{Δ} and {Δ}{Δ} systems: Some {Δ}{Δ} channels are found to have attractive core potentials and may accommodate ``molecular'' bound states near threshold. Finally we use our Born formalism to calculate the NN differential cross section, which we compare with experimental results for unpolarized proton-proton elastic scattering. We find that several familiar features of the experimental differential cross section are reproduced by our Born-order result.