A critical phenomenological study of inclusive photon production in hadronic collisions
P. Aurenche1 - M. Fontannaz2 - J.Ph. Guillet1 - B. Kniehl3 - E. Pilon1 - M. Werlen1
1 Laboratoire d'Annecy-le-Vieux de Physique Théorique LAPTH,
B.P. 110, F-74941 Annecy-le-Vieux Cedex, France
2 Laboratoire de Physique Théorique et Hautes Energies LPTHE, Bât. 211, Université de Paris-Sud, F-91405 Orsay Cedex, France
3 Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, D-80805 München, Germany
Received: 23 November 1998 / Published online: 22 March 1999
We discuss fixed target and ISR inclusive photon production and attempt a comparison between theory and experiments. The dependence of the theoretical predictions on the structure functions, and on the renormalization and factorization scales is investigated. The main result of this study is that the data cannot be simultaneously fitted with a single set of scales and structure functions. On the other hand, there is no need for an additional primordial kT to force the agreement between QCD predictions and experiments, with the possible exception of one data set. Since the data cover almost overlapping kinematical ranges this raises the question of consistency among data sets. A comparative discussion of some possible sources of experimental uncertainties is sketched.