Photoproduction of positive pions on deuterium near threshold

Abstract

The ${\ensuremath{\pi}}^{+}$ photoproduction on deuterium near threshold was measured and compared to the same process in hydrogen. The cross section for deuterium was extracted with a \ifmmode\pm\else\textpm\fi{} 2.5% accuracy for energies ranging from 1 to 4 MeV above threshold. The comparison of our result with theoretical estimates shows that the process is correctly understood in the frame of the impulse approximation.NUCLEAR REACTIONS $^{2}\mathrm{H}(\ensuremath{\gamma},{\ensuremath{\pi}}^{+})$, measured $\ensuremath{\sigma}$, $E=1\ensuremath{-}4$ MeV.