Study Of Polarized Proton Diffraction Dissociation In The Reaction P-Up-P-]Pi+Pi-P At 11975 Gev/C

We present angular distributions and, for the first time, single-spin correlations in the diffraction-dissociation reaction ${p}_{\ensuremath{\uparrow}}$p\ensuremath{\rightarrow}p${\ensuremath{\pi}}^{+}$${\ensuremath{\pi}}^{\mathrm{\ensuremath{-}}}$p, for small momentum transfers between the polarized beam and the (p${\ensuremath{\pi}}^{+}$${\ensuremath{\pi}}^{\mathrm{\ensuremath{-}}}$) system, at 11.75 GeV/c. The only structures seen in our 2\ifmmode\times\else\texttimes\fi{}${10}^{6}$-event sample turn out to be the well-known threshold enhancement in \ensuremath{\Delta}\ensuremath{\pi} and the N(1700), which appears to involve both \ensuremath{\Delta}\ensuremath{\pi} and N(1520)\ensuremath{\pi}. The production process exhibits a slope-mass correlation and patterns of helicity nonconservation seen in higher-energy diffractive processes. We also see evidence for a complex helicity structure in the spin correlations. We show that the threshold enhancement is unambiguously S wave in character, while the N(1700) appears to be a mix of states. The overall similarities between our data and those at higher energies, together with the rich structures contained in the angular-distribution correlations (we measure 315 joint moments in each mass and t bin), make our data base highly relevant for theoretical analysis of exclusive diffraction.