Vector meson production from a polarized nucleon

We provide a framework to analyze the electroproduction process ep -> ep rho with a polarized target, writing the angular distribution of the rho decay products in terms of spin density matrix elements that parameterize the hadronic subprocess gamma* p -> rho p. Using the helicity basis for both photon and meson, we find a representation in which the expressions for a polarized and unpolarized target are related by simple substitution rules