Photoproduction of Negative Pions from Hydrogen at Forward Angles

The recent theoretical investigation by Drell [1] of the photoproduction of very high energy particles at small angles predicts a large peak in differential cross section in this region. In particular, if one applies his results to the photoproduction of negative pions from hydrogen one obtains a value for the differential cross section that is several times larger than the value measured in pair production experiments at larger angles and lower energies. This interesting result has prompted the experimental investigation reported here.