PI+ PRODUCTION WITH LINEARLY POLARIZED PHOTONS

Single π+ production on protons by linearly polarized photons of 2.5 to 5 GeV was measured at squared four momentum transfers t between -0.01 and -0.6 (GeV/c)2. The results show that the differential cross section dσ⊥ dt with the electric vector of the photon perpendicular to the reaction plane is much larger than dσ{norm of matrix} dt with the electric vector parallel to the reaction plane. The predictions of Regge models and of the vector meson dominance model are briefly discussed. © 1969.