  The rates for diffractive quarkonium plus prompt-photon associated production
at the LHC are estimated. The theoretical framework considered in the J/Psi (or
Upsilon) production associated with a direct photon at the hadron collider is
the non-relativistic QCD (NRQCD) factorization formalism. The corresponding
single diffractive cross section is computed based on the hard diffractive
scattering factorization supplemented by absorptive corrections. Such processes
are sensitive to the gluon content of the Pomeron at small Bjorken-x and they
may also be a good place to test the different available mechanisms for
quarkonium production at hadron colliders.

High Energy Physics - Phenomenology