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 $ζ$ 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 $ζ\approx 0.02$ and show that the smallness of this value may point toward softness of the deuteron at short NN distances.