FACTORIZATION AND SOFT-GLUON DIVERGENCES IN ISOLATED-PHOTON CROSS-SECTIONS - ART. NO. 094025

We study the production of isolated photons in e(+)e(-) annihilation a nd give the proof of the all-order factorization of the collinear sing ularities. These singularities are absorbed in the standard fragmentat ion functions of partons into a photon, while the effects of the isola tion are consistently included in the short distance cross section. We compute this cross section at order alpha(s) and show that it contain s large double logarithms of the isolation parameters. We explain the physical origin of these logarithms and discuss the possibility to res um them to all orders in alpha(s). [S0556-2821(98)09119-X].