Measurement of the polarization parameter in $\pi^{+}p$ backward elastic scattering at 6 GeV/c

The polarization parameter in pi /sup +/p backward elastic scattering at 6 GeV/c incident pion momentum has been measured using a butanol polarized proton target, a high intensity pion beam, and a scintillation hodoscope detection system. Details of the apparatus and data analysis are presented here, together with the final results. The polarization appears to be very nearly zero for small u-values, but becomes large and negative for u-values beyond the dip in the pi /sup +/p cross section at u=-0.15 (GeV/c)/sup 2/. The data are not well predicted by any of the current Regge-exchange models. (20 refs)