Properties of the low-massωpenhancement observed inpp↑→pωpat 11.75 GeV/c

Abstract

Samples of the reaction $p_{\ensuremath{\uparrow}}p\ensuremath{\rightarrow}p\ensuremath{\omega}p$, consisting of 20 000 and 1000 events at 11.75 and 6 GeV/c, respectively, were obtained using the Zero Gradient Synchrotron polarized proton beam and the Effective Mass Spectrometer. A narrow enhancement near threshold is seen in the $\ensuremath{\omega}p$ mass distribution. The $t$ distribution of this enhancement shows a pronounced dip near $t=\ensuremath{-}0.2$ Ge${\mathrm{V}}^{2}$ at both beam momenta, suggesting that $\ensuremath{\omega}$ exchange is the dominant production mechanism. The joint-decay-angular-distribution moments and polarization correlations have been determined as functions of $\ensuremath{\omega}p$ mass. Amplitude analysis of these moments indicates that the low-mass enhancement is due to the high-mass tails of spin-parity ${\frac{3}{2}}^{\ensuremath{-}}$ and ${\frac{3}{2}}^{+}$ states below $\ensuremath{\omega}p$ threshold. Polarization correlations consistent with zero provide evidence for the lack of resonant behavior in the low-mass enhancement itself.