Coherent pi0 Photoproduction on the Deuteron

The differential scattering cross section for the process gamma d {yields} d pi{sup 0} was measured, as part of experiment E89-012 at Thomas Jefferson National Accelerator Facility. The experiment was performed in Hall C during the Spring of 1996 as the commissioning experiment for the Hall C cryogenic target. The High Momentum Spectrometer was used to detect the recoil deuteron and no effort was made to detect the pi{sup 0} or its decay photons. The differential cross section was measured at a number of incident photon energies between 0.8 GeV and 4.0 GeV for the center-of-mass angles of 90 degrees and 136 degrees. The data were found to disagree with both the constituent counting rule and reduced nuclear amplitude predictions. These are the first data at large deuteron center-of-mass angles for photon energies larger than 1.6 GeV.