Related papers: Timelike Compton scattering on a spin-0 target wit…
In the framework of collinear QCD factorization, the leading twist scattering amplitudes for deeply virtual Compton scattering (DVCS) and timelike Compton scattering (TCS) are intimately related thanks to analytic properties of leading and…
Deeply virtual Compton scattering (DVCS) and timelike Compton scattering (TCS) leading twist amplitudes are intimately related thanks to their analytic properties as a function of $Q^2$. We exploit this feature to use Compton form factors…
Combining dispersion and operator product expansion techniques, we derive the conformal partial wave decomposition of the virtual Compton scattering amplitude in terms of complex conformal spin to twist-two accuracy. The perturbation theory…
We review recent progress in the study of timelike Compton scattering (TCS), the crossed process of deeply virtual Compton scattering. We emphasize the need to include NLO corrections to any phenomenological program to extract Generalized…
We emphasize the complementarity of timelike and spacelike studies of deep exclusive processes, taking as an example the case of timelike Compton Scattering (TCS) i.e. the exclusive photoproduction of a lepton pair with large invariant…
Using the formalism developed in [1,2] we carry out the first complete calculation of kinematic power corrections to the helicity amplitudes of deeply-virtual Compton scattering to the twist-four accuracy for a study case of a…
The sub-leading power of the scattering amplitude for deeply-virtual Compton scattering (DVCS) off the nucleon contains leading-twist and twist-3 generalized parton distributions (GPDs). We point out that in DVCS, at twist-3 accuracy, one…
In this paper we include kinematic power corrections up to twist-four to the deeply virtual Compton scattering dispersion relation. We demonstrate that, both for (pseudo-)scalar and spin-$1/2$ targets, the formal expression of the…
We study the deeply virtual Compton scattering off a spin-one particle, which is exemplified by the case of coherent scattering on a deuteron target. We discuss the role of twist three contributions for restoring the QED gauge invariance of…
We carry out the first complete calculation of kinematic power corrections $\sim t/Q^2$ and $\sim m^2/Q^2$ to several key observables in Deeply Virtual Compton Scattering. The issue of convention dependence of the leading twist…
Timelike Compton scattering (TCS) i.e. the exclusive photoproduction of a lepton pair with large invariant mass nicely complements the already successful experimental study of deeply virtual Compton scattering (DVCS). The same Generalized…
We calculate $(\sqrt{-t}/Q)^k $ and $(m/Q)^k$ power corrections with $k\le 4$, where $m$ is the target mass and $t$ is the momentum transfer, to several key observables in Deeply Virtual Compton Scattering (DVCS). We find that the power…
We compute the amplitude of deeply virtual Compton scattering (DVCS) using the calculus of QCD string operators in coordinate representation. To restore the electromagnetic gauge invariance (transversality) of the twist-2 amplitude we…
We calculate spin, charge, and azimuthal asymmetries in deeply virtual Compton scattering at leading twist-two level. The measurement of these asymmetries gives an access to the imaginary and real part of all deeply virtual Compton…
The amplitude of the deeply virtual Compton scattering off nucleon is computed to the twist-3 accuracy in the Wandzura-Wilczek (WW) approximation. The result is presented in the form which can be easily used for the analysis of DVCS…
We evaluate the leading-order QED radiative corrections to the timelike Compton scattering (TCS) process $\gamma p \to l^- l^+ p$. We study these corrections in two energy regimes using different models for the TCS amplitude. In the…
We carry out the first complete calculation of kinematic power corrections ~t/Q^2 and ~m^2/Q^2 to the helicity amplitudes of deeply virtual Compton scattering. This result removes an important source of uncertainties in the QCD predictions…
Measurements of deeply virtual Compton scattering (DVCS) made at HERMES using 27.6 GeV $e^\pm$ beams and various internal polarized or unpolarized gaseous targets are discussed. Results are reported on the transverse target-spin asymmetry…
The existing QCD predictions for the Deeply Virtual Compton Scattering (DVCS) depend on the convention used for the skewedness parameter and on the reference frame used to define helicity amplitudes. These ambiquities are formally…
Deeply Virtual Compton Scattering in the near forward kinematic region is the golden access to Generalized Parton Distributions. We studied the O(alphaS) corrections to the scattering amplitude for both spacelike and timelike kinematics…