DVCS via color dipoles: Nonperturbative effects

Abstract

We study the DVCS amplitude within the color dipole approach. The light-cone wave function of a real photon is evaluated in the instanton vacuum model. Our parameter free calculations are able to describe H1 data, both the absolute values and the $t$-dependences, at medium-high values of $Q^2$. The $Q^2$ dependence is found to be sensitive to the choice of the phenomenological cross section fitted to DIS data.

Comments: 11 pages; references added, bibliographic inaccuracy corrected