Color transparency in π- Induced dilepton production on nuclei

We argue that the observation of the color-transparency effect in the semiexclusive A(π-,l+l-) process is important for determining whether it is possible to extract the generalized parton distributions of the nucleon from the elementary reaction π-p→l+l-n at plab=15-20 GeV/c at small |t| and large invariant mass of the dilepton pair l+l-. Assuming that the transverse size of the pionic qq pair in the hard interaction point is similar to the one in the reaction γ∗p→π+n studied at JLab, we predict large color-transparency effects in the discussed kinematic range. We also suggest that the semiexclusive ρ0 production in π - induced reactions in the same beam momentum region may provide new information on the dynamics of the interaction in the nonvacuum channel, while the J/ψ production can be used to get information on J/ψN total interaction cross section.