On the description of exclusive processes beyond the leading twist approximation

Abstract

We describe hard exclusive processes beyond the leading twist approximation in a framework based on the Taylor expansion of the amplitude around the dominant light-cone directions. This naturally introduces an appropriate set of non-perturbative correlators whose number is minimalized after taking into account QCD equations of motion and the invariance under rotation on the light-cone. We examplify this method at the twist 3 level and show that the coordinate and momentum space descriptions are fully equivalent.

Figures (1)

• Figure 1: 2- and 3-body correlators attached to a hard scattering amplitude in the example of the $\gamma^* \to \rho$ impact factor.