Constraints on vector meson photoproduction spin observables - art. no. 015501

Extraction of spin observables from vector meson photoproduction on a nucle on target is described. Starting from density matrix elements in the vector meson's rest frame, we transform to spin observables in the photon-nucleon c.m. frame. Several constraints on the transformed density matrix and on t he spin observables follow from requiring that the angular distribution and the density matrix be positive definite. A set of constraints that are req uired in order to extract meaningful spin observables from forthcoming data are enunciated.