From the matching of soft-wall AdS/QCD and light-front QCD for electromagnetic form factors of hadrons with arbitrary twist, we derive an effective light-front wave function (LFWF). The scale at which such matching is performed is set as an initial scale. Together with the LFWF, we also obtain expressions for parton distribution functions (PDFs) and generalized parton distributions (GPDs) at this scale. Doing the hard evolution of PDFs and GPDs, we show that these quantities obey model-independent constraints imposed, e.g., by the Drell-Yan-West duality at large $x$ and large scales, while the hadronic form factors at large momenta are in full agreement with quark counting rules. We finally propose a phenomenological light-front wave function for hadrons with arbitrary twist dimension (mesons, baryons, and multiquark states). It explicitly depends on the scale. The wave function evolves from the expression at the initial scale predicted by soft-wall AdS/QCD to high scales, where it gives the correct scaling behavior of PDFs, GPDs, and form factors for both pions and nucleons. For other hadronic states, the proposed wave function produces form factors consistent with quark counting rules and gives predictions for parton distributions. As an application, we build a light-front quark model for nucleons based on the proposed wave function.

• Received 4 June 2013

DOI:https://doi.org/10.1103/PhysRevD.89.054033