On the Analysis of Vector-meson Production by Polarized Photons ~

The formalism necessary to analyze production of vector mesons with polarized photons (~p --*pV) is.presented in detail. The decay angular distribution of the vector mesons is parameterized by the density matrices pOl, 0t = 0, 1, 2, 3. Restrictions on the numerical values of the density matrix elements are derived. From the symmetry properties of the helicity amplitudes, it is shown that at high o i_l~knl energies the combinations Pkk ' =F , ' ~-kk' to leading order in energy receive only contributions from natural (unnatural) parity exchange in the t-channel. It is shown that this is true in any coordinate system which can be reached from the vector-meson helicity system by a rotation around the normal to the production plane. The values of the density matrices as predicted by various models: elementary 0 :~ exchange, spin independence, helicity conservation, are given.