Photon production via deep inelastic quark and gluon fragmentation is studied beyond the leading perturbative order within the framework of a specific factorization scheme ($\mathrm{DI}{\mathrm{S}}_{\gamma }$) chosen to provide the maximally possible amount of perturbative stability. It is argued that the perturbative (pointlike) results are expected to present a realistic estimate for photonic fragmentation functions, and the ambiguities related to the presently unknown, but possibly small, nonperturbative hadronic contributions are pointed out.

• Received 1 February 1993

DOI:https://doi.org/10.1103/PhysRevD.48.116