Probing Transversity in Electroproduction of Two Vector Mesons
  Electroproduction of two vector mesons with a large rapidity gap between them provides the first feasible selective access to chiral-odd GPDs.   The scattering amplitude of the process $ \gamma ^* N \to \rho_L^0 \rho_T^+ N'$ may be represented as a convolution of an impact factor describing the $\gamma ^* \to \rho_L^0$ transition and an amplitude describing the $N\to \rho_T^+ N'$ transition, analogously to deeply exclusive electroproduction of a meson, the virtual photon being replaced by a Pomeron. The production of a transversely polarized vector meson $\rho_T^+$ selects a chiral-odd GPD in the proton. 
D.Yu. Ivanov, B. Pire, L. Szymanowski and O.V. Teryaev