  An explicit evaluation of the double parton distribution functions (dPDFs),
within a relativistic Light-Front approach to constituent quark models, is
presented. dPDFs encode information on the correlations between two partons
inside a target and represent the non-perturbative QCD ingredient for the
description of double parton scattering in proton-proton collisions, a crucial
issue in the search of new Physics at the LHC. Valence dPDFs are evaluated at
the low scale of the model and the perturbative scale of the experiments is
reached by means of QCD evolution. The present results show that the strong
correlation effects present at the scale of the model are still sizable, in the
valence region, at the experimental scale. At the low values of x presently
studied at the LHC the correlations become less relevant, although they are
still important for the spin-dependent contributions to unpolarized proton
scattering.
