Energy-Dependence Of Backward Pi+P Elastic-Scattering From 2 To 6 Gev-C

The energy dependence of backward ${\ensuremath{\pi}}^{+}p$ elastic scattering has been measured for incident $\ensuremath{\pi}$ momenta 2.0-6.0 GeV/c in steps of typically 100 MeV/c. Values are presented for both the differential cross section extrapolated to 180\ifmmode^\circ\else\textdegree\fi{} and the slope of the backward peak as a function of momentum. In the $s$ channel we see the effects of the established ${\ensuremath{\Delta}}^{++}$ resonances and evidence for the $\ensuremath{\Delta}(3230)$. Also, the data show the existence of a negative-parity $\ensuremath{\Delta}$ resonance with mass \ensuremath{\sim}2200 MeV/${\mathit{c}}^{2}$.