Photoproduction of ${\pi }^0$-Mesons on the Nucleon and Deuteron

The photoproduction of ${\pi }^0$-mesons from the nucleon and deuteron has been studied for incidents of photon energies up to 1.5 GeV. By using the MAID-2007 model for the process on the nucleon, we predict results for the unpolarized and helicity-dependent total cross sections of the semi-exclusive reaction $\gamma d\to {\pi }^{0}X$ ($X=np+d$) with the inclusion of rescattering effects. We find that rescattering effects yield a substantially large contribution. The extracted results are compared with the available experimental data and a satisfactory agreement is obtained. In addition, the contribution of $\gamma d\to {\pi }^{0}X$ ($X=np+d$) to the finite GDH integral has been evaluated by explicit integration up to 1.5 GeV and a total value of 256.96 $\mu$b has been obtained. Convergence of the GDH integral has been reached.