Soft-gluon resummation and NNLO corrections for direct photon production -art. no. 094004

The resummation of threshold logarithms for direct photon production cross sections in hadronic collisions is presented. The resummation is based on t he factorization properties of the cross section and is formulated at next- to-leading logarithmic or higher accuracy. Full analytical and numerical re sults for the next-to-next-to-leading order expansion of the resummed cross section are given. A substantial reduction of factorization scale dependen ce is observed. A comparison to experimental results from the E-706 and UA- 6 experiments is presented.