Simplified Regge Analysis of Backwardπ+pScattering

Abstract

Polarization and differential-cross-section data for backward ${\ensuremath{\pi}}^{+}p$ scattering are explained in terms of a model which includes the ${N}_{\ensuremath{\alpha}}$ Regge pole plus a background term which one may interpret as either a secondary pole or cut. This model, although simplifying the number of exchanges, provides an excellent fit to the data. The dip-bump structure and polarization are related. The rise of the differential cross section after the dip is shown in this model to be due in part to the background term rather than solely the recovery of the ${N}_{\ensuremath{\alpha}}$ Regge-pole term from zero due to the vanishing of $\ensuremath{\alpha}\ensuremath{-}\frac{1}{2}$ near $u=\ensuremath{-}0.14$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$.