Related papers: Cross sections and spin asymmetries in vector meso…
In this report we calculate the cross section and $A_{ll}$ asymmetry for the diffractive $J/\Psi$ leptoproduction. We study dependences of the asymmetry on the structure of the Pomeron-proton coupling
We consider hard leptoproduction of a photon on a spin-one target and give the general azimuthal angular dependence of the differential cross section. Furthermore, we estimate the beam spin asymmetry for an unpolarized deuteron target at…
Azimuthal asymmetry of vector-meson production in single-transversely polarized proton-proton collisions ($p\up p$) is calculated in the string model of particle production. The asymmetry is generated only during fragmentation of a…
By using a Regge-pole model for vector meson production (VMP), that successfully describes the HERA data, we analyze the connection of VMP cross sections in photon-induced reactions at HERA with those in ultra-peripheral collisions at the…
Evidence for a positive longitudinal double-spin asymmetry <A_1^rho> = 0.24 +-0.11 (stat) +-0.02 (syst) in the cross section for exclusive diffractive rho^0(770) vector meson production in polarised lepton-proton scattering was observed by…
We analyze the light meson leptoproduction within the handbag approach. We show that effects determined by the transversity Generalized Parton Distributions (GPDs), $H_T$ and $\bar E_T$ are essential in the description of pseudoscalar and…
We calculate the differential cross section for real photon electroproduction off spinless hadron which sevres as a main probe of the hadrons structure via the concept of generalized parton distributions. Compared to previously available…
General expressions for the unpolarized differential cross section and for various polarization observables in the coherent pseudoscalar meson photo- and electroproduction on the deuteron target have been obtained in one-photon-exchange…
A simple model-independent formula for cross-section asymmetries $A$ in fermion-pair production is derived, which may be used for the analysis of LEP~1 data, $A = \sum_n A_n (s - M_Z^2)^n$. The coefficient $A_0$ depends on the $Z$ boson…
We discuss recent HERA results on vector--meson electroproduction gamma*p -> Vp and demonstrate that universality of the initial and final state interactions responsible for the transition between the on- and off-mass shell states allows to…
The energy dependence of cross sections is discussed as a way to learn about the dynamics of photon induced interactions at HERA. The question of determining the scale of exclusive electroproduction of vector mesons is addressed.
By using a Regge-pole model for vector meson production (VMP), successfully describing the HERA data, we analyse the correlation between VMP cross sections in photon-induced reactions at HERA and those in ultra-peripheral collisions at the…
We calculate the cross section and the $A_{ll}$ asymmetry of the diffractive vector meson leptoproduction for a simple model of the pomeron coupling with the proton. It is found that the sensitivity of the spin--dependent cross section of…
We consider the leading order result for polarized leptoproduction, putting emphasis on transverse momentum dependent effects appearing in azimuthal asymmetries. Measurements of weighted cross sections enable extraction of the distribution…
We investigate the longitudinal and transverse polarized cross-sections of the leptoproduction of the rho meson in the high energy limit. Our model is based on the computation of the impact factor gamma*(lambda_gamma) -> rho(lambda_rho)…
It is shown that the longitudinal double spin asymmetry $A_{ll}$ in polarized diffractive $Q \bar Q$ production depends strongly on the spin structure of the quark-pomeron vertex. Relevant experiments will be possible at HERA with a…
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…
We analyze electroproduction of light vector meson at small Bjorken $x$ within the generalized parton distribution (GPD) approach. Calculation is based on the modified perturbative approach, where the quark transverse degrees of freedom in…
Results on elastic vector meson production at HERA are presented in the framework of perturbative QCD. The energy dependence of the cross section for J/Psi photoproduction and for rho electroproduction is studied. A full polarisation…
The energy dependence of the cross section for exclusive electroproduction of vector mesons is discussed as a way to learn about the interplay of soft and hard interactions. The question of determining the scale of these processes is…