Diffractive production of quarkonia

Abstract

I discuss two selected examples of diffractive production of quarkonia: $p p \to p \eta' p$ and $p p \to p J/\psi p$. In the first case I consider diffractive pQCD approach and $\gamma \gamma$ fusion, in the second case the amplitude is linked to the amplitude of the process for $J/\psi$ photoproduction at HERA. Absorption effects are discussed briefly for the second reaction.