Multibody Photoproduction between 2 and 16 GeV

The SLAC 2.2-m streamer chamber has been used to study photoproduction from hydrogen with a 16-GeV bremsstrahlung beam. The use of a single-hadron trigger permitted a study from 2 16 GeV which included photoproduction of the A* and of the vector mesons p , w, and Cp. The sample reported here represents 87,000 pictures containing 7,055 hadronic events of which about 2,500 were above 5 GeV. Interesting aspects of the data are: the dominance of p’_production in the S-prong topology at high energies; the diffraction character of high energy P” production; the clear indication of the transversality of the PO spin orientation; the apparent interference between the resonant r+~( p”) production and a nonresonant background. Tests of the vector dominance model are described including a comparison of total photoproduction cross sections derived from our data with those obtained elsewhere by direct measurements.