Generalized Valon Model for Double Parton Distributions
  We show how the double parton distributions may be obtained consistently from the many-body light-cone wave functions. We illustrate the method on the example of the pion with two Fock components. The procedure, by construction, satisfies the Gaunt-Stirling sum rules. The resulting single parton distributions of valence quarks and gluons are consistent with a phenomenological parametrization at a low scale. 
Wojciech Broniowski, Enrique Ruiz Arriola, Krzysztof Golec-Biernat
hep-ph nucl-th