Scattering ofπ−Mesons in the Momentum Range 875-1579 MeV/cfrom a Polarized Proton Target

Measurements have been made of the asymmetry in the scattering of ${\pi }^{-}$ mesons by a polarized proton target. Scattered $\pi$ mesons and recoil protons were detected in arrays of scintillation counters; data were obtained at 16 scattering angles at each of 8 beam momenta between 875 and 1578 MeV/c. Analysis of these data together with earlier differential-cross-section measurements shows that there must exist at least three resonances in this energy region: (i) mass 1920 MeV/${\mathit{c}}^2$, $\Gamma =170\mathrm{}$ MeV/${\mathit{c}}^2$, $I=\frac{3}{2}$, $F_{\frac{7}{2}}$; (ii) mass 1682 MeV/${\mathit{c}}^2$, $\Gamma =100\mathrm{}$ MeV/${\mathit{c}}^2$, $I=\frac{1}{2}$, $F_{\frac{5}{2}}$; and (iii) mass 1674 MeV/${\mathit{c}}^2$, $\Gamma =100\mathrm{}$ MeV/${\mathit{c}}^2$, $I=\frac{1}{2}$, $D_{\frac{5}{2}}$.