  Two-pion photoproduction in the reaction gamma p -> p pi+ pi- has been
studied at Jefferson Lab Hall B using a circularly-polarized tagged photon beam
in the energy range between 0.6 GeV and 2.3 GeV. Beam-helicity-dependent
angular distributions of the final-state particles were measured. The large
cross-section asymmetries that have been found exhibit strong sensitivity to
the kinematics of the reaction, and are compared with preliminary model
calculations by Mokeev and Roberts.
