You might be interested in hep-ex/9708032 "The Photoproduction of the
b1(1235)\pi System", performed in the SLAC hydrogen bubble chamber
using a backscattered laser photon beam. Besides diffractive b1\pi
production, they also see a large Delta++ signal.
Jim
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Jim Napolitano email: jimnap@rpi.edu
Dept of Physics phone: (518)276-8019/6310
Rensselaer Polytechnic Institute FAX: (518)276-6680
Troy, NY 12180-3590 WWW: http://www.rpi.edu/~napolj