A REGGE POLE ANALYSIS OF PION-PROTON CHARGE EXCHANGE POLARIZATION.

The negative-pion-proton charge exchange reaction negative-pion p to neutral-pion n at high energy and low momentum transfer provides an excellent test of the Regge pole hypothesis. Only the RHO-meson may be exchanged in the crossed channel, t, because only the RHO-meson has I 1, G 1 and P -1 exp. J. The differential cross section dsigmadt was measured in the energy range 6 - 18 GeV. Several analyses have shown the consistency of this data with a single RHO Regge pole exchange. The single Regge pole model predicts zero polarization because the non-spin flip and the spin flip amplitudes have the same phase. A recent measurement at 6 GeV and low momentum transfer shows a non-zero polarization in apparent contradiction to the Regge pole hypothesis. It is demonstrated that this polarization may be explained in terms of the interference of the Regge pole amplitude with the lower lying resonance in the direct channel, s. Predictions of P for vaious values of s and t are made. Author