Excitation of High-Energy Protons into Low-Mass States inp−dInteractions

We have measured $p-d$ inelastic scattering at small momentum transfer by detecting the slow-recoil deuterons from a deuterium-gas-jet target. The coherent diffraction dissociation of protons on deuterons was studied in the region $0.03<\mathrm{}\left|t\right|<0.07\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$, $1.4<\mathrm{}{M_X}^2<4\mathrm{}$ Ge${\mathrm{V}}^2$, and for energies from 50 to 275 GeV. In this region, the diffractive cross section exhibits structure and is dominated by an enhancement at ${M_X}^2\sim 1.9$ Ge${\mathrm{V}}^2$.