Asymmetries in Charged-Pion Photoproduction on Nucleons by 16-GeV Polarized Photons

Abstract

Asymmetries in charged-pion photoproduction from hydrogen and deuterium have been measured with 16-GeV linearly polarized photons. Considerable energy dependence is seen in the natural-parity contribution to the $\frac{{\pi }^{-}}{{\pi }^{+}}$ ratio from deuterium, and in the unnatural-parity part of the cross section for $\gamma n\to {\pi }^{-}p$. The energy dependence of this latter cross section is consistent with the expected from a conventional pion Regge trajectory.