Related papers: Hard diffractive electroproduction of vector meson…
A model example is given of how properties of the hadronic light-cone wave function are revealed in a particular high energy process. The meson wave function is derived in scalar quark QCD. We apply it to compute the form of the cross…
The elastic electroproduction of phi mesons is studied at HERA with the H1 detector for photon virtualities 1 < Q^2 < 15 GeV^2 and hadronic centre of mass energies 40 < W < 130 GeV. The Q^2 and t dependences of the cross section are…
Lattice QCD can provide a direct determination of meson electromagnetic form factors, making predictions for upcoming experiments at Jefferson Lab. The form factors are a reflection of the bound-state nature of the meson and so these…
The H1 and ZEUS collaborations at HERA report new data on the diffractive production of vector mesons with a many-fold increase of luminosity compared to previous measurements. The new data include photoproduction and electroproduction of…
We demonstrate that perturbative QCD allows one to calculate the absolute cross section of diffractive exclusive production of photons at large $Q^2$ at HERA, while the aligned jet model allows one to estimate the cross section for…
We analyze electroproduction of light vector mesons at small Bjorken-x in an approach that includes the gluonic generalized parton distributions and a partonic subprocess, gamma g --> (q q-bar) g, q q-bar --> V. The subprocess is calculated…
Including destructively interfering off-diagonal transitions of diffraction-dissociation type, we arrive at a formulation of GVD for exclusive vector-meson production in terms of a continuous spectral representation of dipole form. The…
We evaluate the leading order amplitude for the deep exclusive electroproduction of an exotic hybrid meson in the Bjorken regime. We show that, contrary to naive expectation, this amplitude factorizes at the twist 2 level and thus scales…
We summarise recent progress in the computation of helicity amplitudes for diffractive vector meson production at large momentum transfer and their comparison to data collected at the HERA collider.
Measurements and theoretical calculations of meson form factors are essential for our understanding of internal hadron structure and QCD, the dynamics that bind the quarks in hadrons. The pion electromagnetic form factor has been measured…
Recently, a new perturbative QCD factorization formalism for heavy quarkonium production at a large transverse momentum was proposed. Phenomenological application of this new approach relies on our knowledge of a large number of universal…
We compute a light front wave function for heavy vector mesons based on long distance matrix elements constrained by decay width analyses in the Non Relativistic QCD framework. Our approach provides a systematic expansion of the wave…
We discuss exclusive $\phi$-meson electroproduction off the proton near threshold within the GPD factorization framework. We propose the `threshold approximation' in which only the leading term of the conformal partial wave expansion of the…
We calculate the ${\cal O}(\alpha_s^3)$ short-distance, QCD collinear-factorized coefficient functions for all partonic channels that include the production of a heavy quark pair at short distances. This provides the first power correction…
Using clover improved Wilson fermions we calculate thermal vector meson correlation functions above the deconfinement phase transition of quenched QCD. At temperatures 1.5 Tc and 3Tc they are found to differ by less than 15% from that of a…
As a stringent test of the nonrelativistic QCD factorization approach for inclusive heavy-quarkonium production in high-energy hadron collision, the polarized heavy-quarkonium production at the Tevatron is discussed. The polarization of…
We study diffractive vector meson photoproduction using string theory via AdS/CFT. The large $s$ behavior of the cross sections for the scattering of the vector meson $V$ on a proton is dominated by the soft Pomeron, $\sigma_V\sim…
Diffractive vector meson photoproduction accompanied by proton dissociation is studied for large momentum transfer. The process is described by the non-forward BFKL equation which we use to compare to data collected at the HERA collider.
The electromagnetic form factors of vector mesons are calculated in an explicitly Poincar\'e covariant formulation, based on the Dyson--Schwinger equations of QCD, that respects electromagnetic current conservation, and unambiguously…
The dominant mechanism to produce hadronic bound states with large transverse momentum is fragmentation, that is the splitting of a high energy parton into a hadronic state and other partons. We review the present schemes to calculate the…