Breakdown of Conventional Factorization for Isolated Photon Cross Sections

Abstract

Using $e^{+}{e}^{-}\to \gamma +X$ as an example, we show that the conventional factorization theorem in perturbative quantum chromodynamics breaks down for isolated photon cross sections in a well defined part of phase space. Implications and physical consequences are discussed.

11 pages, RevTex, 1 figure in postscript