Power Corrections to QCD Sum Rules for Compton Scattering

Abstract

We extend previous work on sum rules for the invariant amplitudes of pion Compton scattering by deriving a complete lowest order perturbative spectral function - and its leading non perturbative power corr ections - for a specific combination of the two helicities $(H_1+H_2)$ of this process. Using some properties of a modified version of the Borel transform, we develop a method of calculation of the gluonic corrections which can be easily extended to other similar reactions, such as proton Compton scattering. A preliminary comparison of the new sum rule with the pion form factor sum rule is made.

Comments: 24 pages in latex 5 figures not includes availiable upon request (email: claudio@max.physics.sunysb.edu), ITP-US-93-3 preprint