Cut Conspiracy and Pion Evasion inπ+andπ−Photoproduction

Abstract

We propose a four-trajectory model to interpret ${\pi }^{+}$ and ${\pi }^{-}$ photoproduction off nucleons. The model makes use of evading $\pi$ and $\rho$ trajectories, an evading $\rho P$ cut, and a conspiring $\pi P$ cut. The model is found to be in good agreement with ${\pi }^{+}$ photoproduction data for lab $\gamma$-ray energies ranging from 2 to 16 GeV and $\mathrm{}\left|t\right|\mathrm{}$ values ranging from ${10}^{-4\mathrm{}}$ to $2.0 {\left(\frac{\mathrm{GeV}}{c}\right)}^2$. It is also found to be in good agreement with the observed $t$-dependent ratio of ${\pi }^{-}$ to ${\pi }^{+}$ photoproduction at 3.4 and 5 GeV. Predictions are made for high-energy charged photomeson production cross sections in which the bombarding photon is polarized.