Associated jpsi + gamma production through double Pomeron exchange: The   nature of the Pomeron and hard diffractive factorization breaking
  We present a study of associated jpsi + gamma production through double Pomeron exchange at energies reached at the Fermilab Tevatron and CERN LHC based on the Ingelman-Schlein model for hard diffractive scattering and the factorization formalism of nonrelativistic QCD for quarkonia production. We find that this process (p + pbar \to p + pbar + jpsi + gamma + X) can be used to probe the gluon content of the Pomeron and study the natrue of hard diffractive factorization breaking. 
Jia-Sheng Xu and Hong-An Peng (Peking Unv.)