Interference of ReggeϱExchange with Direct Channel Fermion Resonances

Abstract

Using a Reggeized $\rho$-meson-exchange background amplitude, information on $Y=+1\mathrm{}$ fermion resonances is obtained from a calculation of the energy dependence of (i) the difference of the ${\pi }^{-}p$ and ${\pi }^{+}p$ total cross sections and (ii) the ${\pi }^{-}p\to {\pi }^{0}n$ differential cross section at zero degrees. Some evidence is found for a new $I=\frac{1}{2}$ resonance at 3350 MeV that might be a further Regge recurrence of the $N_{\gamma }$ trajectory. Study of the charge-exchange data confirms the validity of the Regge prediction for the phase of the background amplitude.