Measurements of Singleπ−andπ+Photoproduction at Small Momentum Transfers

Single ${\pi }^{-}$ and ${\pi }^{+}$ photoproduction from deuterium has been measured at gamma energies of 3.4 and 5 GeV and momentum transfers between 0.005 and 0.6 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. The $\frac{{\pi }^{-}}{{\pi }^{+}}$ ratio is found to be unity near the forward direction and drops to about 0.3 at larger angles. The data support the existence of a forward peak in ${\pi }^{-}$ photoproduction on neutrons.