Fermi Motion and Quark Off-Shellness in Elastic Vector-Meson Production
  We study ways of implementing Fermi momentum in elastic vector-meson production, and find that the usual on-shell assumption of quark models and quark wave functions cannot reproduce the ratio of the longitudinal cross section to the transverse one. We propose a new approach which allows the quarks to be off-shell, and which naturally reproduces the data. As a consequence, we prove that the asymptotic form of the transverse cross section is different from 1/Q^8. In this new model, we show that the mass, t and Q2 dependence of the cross sections are also reproduced. We also make predictions concerning the production of excited states such as the rho' and the psi'. 
I. Royen and J.R. Cudell