K+-Proton Elastic Scattering at 910 MeV/c; Polarization of the Recoil Protons

The Berkeley 30-in. propane bubble chamber was used to study the elastic $K^{+}$-proton interaction at 910 MeV/c. This is the region of transition from the isotropy in angular distribution found below 810 MeV/c to the rapidly increasing anisotropy above 1 BeV/c. Results based on 1154 events show that the series ($1+a{{cos\theta }_K}^{\mathrm{c}.\mathrm{m}.\mathrm{}}$) can fit the angular distribution with $a=0.18\mathrm{}\pm 0.05$. Polarization was measured on the secondary proton by using 53 proton-proton and 41 proton-carbon recoils in the liquid of the chamber. The results of a phase-shift analysis incorporating these polarization data are presented.