AssociatedJ/ψ+γdiffractive production: The nature of the Pomeron and a test of hard diffractive factorization

Abstract

We present a study of diffractive associated $J/\ensuremath{\psi}+\ensuremath{\gamma}$ production 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 $(p+\overline{p}\ensuremath{\rightarrow}p+J/\ensuremath{\psi}+\ensuremath{\gamma}+X)$ can be used to probe the gluon content of the Pomeron and test the assumption of diffractive hard scattering factorization. Using the renormalized Pomeron flux factor $D\ensuremath{\simeq}0.11(0.052)$ at Tevatron (LHC) energy, the single diffractive associated $J/\ensuremath{\psi}+\ensuremath{\gamma}$ production cross section in the region of $4<{P}_{T}<10\mathrm{GeV},$ $\ensuremath{-}1<\ensuremath{\eta}<1$ is found to be of the order of 3.0 pb (8.5 pb). The ratio of single diffractive to inclusive production is 0.50% (0.15%) in the central region at the Tevatron (LHC) for the gluon fraction in the Pomeron ${f}_{g}=0.7,$ independent of the values of the color-octet matrix elements.