Short-range NN properties in the processes $pd \to dp$ and $pd \to (pp)n$

Abstract.

The data from the first measurement, performed at ANKE/COSY, of the unpolarized cross-section of the reaction $pd \to (pp)n$ in the kinematics of backward elastic $pd \to dp$ scattering at proton beam energies between 0.6 and 1.9 GeV are analyzed in a phenomenological approach. The $pd \to (pp)n$ data and the triplet cross-section of the reaction $pd\to (pn)p$, calculated from the $pd \to dp$ data on the basis of the Fäldt-Wilkin extrapolation, are used here to derive the ratio $\zeta$ of the singlet production matrix element squared to the triplet one. This ratio, defined in our earlier analysis of $pd\to (pn)p$ data in a largely model-independent way, depends on the dynamics of the pd interaction. We find here $\zeta\approx 0.02$ and show that the smallness of this value may point toward softness of the deuteron at short NN distances.