High-energy factorization predictions for the charm structure function F2c at HERA

High-energy factorization predictions for F-2(c) are derived using BFKL descriptions of the proton structure function F-2 at HERA. The model parameters are fixed by a fit of F-2 at small x. Two different approaches of the non-perturbative proton input are shown to correspond to the factorization at the gluon or quark level, respectively. The predictions for F-2(c) are in agreement with the data within the present error bars. However, the photon wave-function formulation (factorization at quark level) predicts significantly higher F-2(c) than both gluon factorization and a next-leading order DGLAP model. (C) 1998 Elsevier Science B.V.