  We propose a phenomenological light-front wave function for hadrons with
arbitrary twist-dimension (mesons, baryons and multiquark states), which gives
the correct scaling behavior of structure functions (parton distributions) and
form factors for pions and nucleons. For other hadronic states the proposed
wave function produces form factors consistent with quark counting rules, and
gives predictions for structure functions (parton distributions). As an
application we build a light-front quark model for nucleons based on the
proposed wave function.
