Photo-production of ${\eta }_{c,b}$ near Threshold

Abstract

We analyze the photo-production of ${\eta }_{c,b}$ off a proton in the threshold region, in terms of C-odd gluonic correlations in the off-forward proton matrix element. Near threshold, the skewness is large leading to a production amplitude that is dominated by four C-odd twist-3 gluon GPDs. We use the QCD instanton vacuum to estimate these C-odd contributions in the proton. The results are used to estimate the differential cross sections for coherent photo-production of ${\eta }_{c,b}$ in the threshold region, at current electron facilities.

25 pages, 9 figures

References in corpus (17)

• Gravitational form factors of the proton from lattice QCD
• $J/\psi$ near threshold in holographic QCD: A and D gravitational form factors
• Measurement of the J/$\psi$ photoproduction cross section over the full near-threshold kinematic region
• Updated analysis of near-threshold heavy quarkonium production for probe of proton's gluonic gravitational form factors
• A QCD analysis of near-threshold quarkonium leptoproduction at large photon virtualities
• Multi-quark matrix elements in the proton and three gluon exchange for exclusive ${\eta }_c$ production in photon-proton diffractive scattering
• Exclusive Two-Vector-Meson Production from e^+ e^- Annihilation
• Systematic analysis of the proton mass radius based on photoproduction of vector charmoniums
• Exclusive ${\eta }_c$ production from small-$x$ evolved Odderon at a electron-ion collider
• Hadronic structure on the light-front V. Diquarks, Nucleons and multiquark Fock components
• Centre vortex structure in the presence of dynamical fermions
• Glue in hadrons at medium resolution and the QCD instanton vacuum
• Photoproduction of C-even quarkonia at EIC and EicC
• Hadronic structure on the light-front VIII. Light scalar and vector mesons
• Hadronic structure on the light-front VII. Pions and kaons and their partonic distributions
• Two-photon decay of pseudoscalar quarkonia
• Threshold photoproduction of ${\eta }_c$ and ${\eta }_b$ using holographic QCD