QCD Sum Rules and Compton Scattering

Abstract

We extend QCD sum rule analysis to moderate energy fixed angle Compton scattering. In this kinematic region there is a strong similarity to the sum rule treatment of electromagnetic form factors, although the four-point amplitude requires a modification of the Borel transform. To illustrate our method, we derive the sum rules for helicity amplitudes in pion Compton scattering and estimate their large-$t$ behavior in the local duality approximation.

Comments: 30 pages in Latex, 6 figures not included, available upon request (send email to: claudio@max.physics.sunysb.edu), ITP-SB-92-70, CEBAF-TH-92-32