Anomalous f_1 exchange in vector meson photoproduction asymmetries
  We perform an analysis of the elastic production of vector mesons with polarized photon beams at high energy in order to investigate the validity of a recently proposed dynamical mechanism based on the dominance of the f_1 trajectory at large momentum transfer. The density matrix characterizing the angular distributions of the vector meson decays is calculated within an exchange model which includes the Pomeron and the f_1. The asymmetries of these decays turn out to be very useful to disentangle the role of these exchanges since their effect depends crucially on their quantum numbers which are different. The observables analyzed are accessible with present experimental facilities. 
Yongseok Oh, Nikolai I. Kochelev, Dong-Pil Min, Vicente Vento, Andrey   V. Vinnikov