Regular Article - Theoretical Physics
Dispersion representations for hard exclusive processes: beyond the Born approximation
Theory Group, Deutsches Elektronen-Synchroton DESY, 22603, Hamburg, Germany
2 Sobolev Institute of Mathematics, 630090, Novosibirsk, Russia
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Published online: 23 October 2007
Several hard exclusive scattering processes admit a description in terms of generalized parton distributions and perturbative hard-scattering kernels. Both the physical amplitude and the hard-scattering kernels fulfill dispersion relations. We give a detailed investigation of their consistency at all orders in perturbation theory. The results shed light on the information about generalized parton distributions that can be extracted from the real and imaginary parts of exclusive amplitudes. They also provide a practical consistency check for models of these distributions in which Lorentz invariance is not exactly satisfied.
© Springer-Verlag / Società Italiana di Fisica, 2007