Coherent pi-0 photoproduction on the deuteron up to 4-GeV

The differential cross section for {sup 2}H({gamma},d){pi}{sup 0} has been measured at deuteron center-of-mass angles of 90{degree} and 136{degree}. This work reports the first data for this reaction above a photon energy of 1 GeV, and permits a test of the apparent constituent counting rule and reduced nuclear amplitude behavior as observed in elastic {ital ed} scattering. Measurements were performed up to a photon energy of 4.0 GeV, and are in good agreement with previous lower energy measurements. Overall, the data are inconsistent with both constituent-counting rule and reduced nuclear amplitude predictions. {copyright} {ital 1999} {ital The American Physical Society}