We ask the question whether the quark and gluon
distributions in the Pomeron obtained from QCD fits to hard diffraction processes at HERA can be dynamically generated from a state made of
valence-like gluons and sea quarks as input. By a method combining
backward Q2-evolution for data exploration and
forward Q2-evolution for a best fit determination, we find that the
diffractive structure
functions published by the H1 Collaboration at HERA can be described by a simple
valence-like input at an initial scale of order
μ22.3–
2.7GeV2. The
parton number sum rules at the initial scale
μ2 for the H1 fit gives
2.1±0.1±0.1 and
0.13±0.01±0.02 for gluon and sea quarks, respectively, corresponding to an initial Pomeron state made of (almost) only two gluons. It has flat gluon density leading to a plausible interpretation in terms of a gluonium state.