Cross Section andT20in O° Deuteron Breakup at 2.1 GeV

Cross sections and $T_{20}$ analyzing powers for $\mathrm{dA}\to \mathrm{pX}$ are presented. A shoulder in the cross section previously reported at higher energies and for carbon is observed for H, C, and Ti at the same $d$-c.m.-frame proton momentum, $q=0.35\mathrm{}$ GeV/c. At $q<\mathrm{}0.2\mathrm{}$ GeV/c both cross-section and $T_{20}$ data depend only weakly upon the target atomic number $A$. Calculations in the plane-wave impulse approximation with several $\mathrm{NN}$ wave functions, and with either a $\Delta \Delta$ or a six-quark component added, are discussed.