Eur. Phys. J. C (2012) 72: 2055
https://doi.org/10.1140/epjc/s10052-012-2055-5

Regular Article - Theoretical Physics

Gauge invariance of DVCS off an arbitrary spin hadron: the deuteron target case

¹ Institute for Theoretical Physics, University of Regensburg, 93040, Regensburg, Germany
² Bogoliubov Laboratory of Theoretical Physics, JINR, 141980, Dubna, Russia
³ Department of Astronomy and Theoretical Physics, Lund University, 223-62, Lund, Sweden
⁴ CPHT, École Polytechnique, CNRS, 91128, Palaiseau, France

^* e-mail: anikin@theor.jinr.ru
^** e-mail: Igor.Anikin@physik.uni-regensburg.de

Received: 8 March 2012
Revised: 4 May 2012
Published online: 24 July 2012

Abstract

We study the deeply virtual Compton scattering off a spin-one particle, as the case for the coherent scattering off a deuteron target. We extend our approach, formulated initially for a spinless case, and discuss the role of twist three contributions for restoring the gauge invariance of the amplitude. Using twist three contributions and relations, which emanate from the QCD equations of motion, we derive the gauge invariant amplitude for the deeply virtual Compton scattering (DVCS) off hadrons with spin 1. Using the derived gauge invariant amplitude, the single spin asymmetry is discussed.