Light front wave functions and diffractive electroproduction of vector mesons

We determine the leading Fock-state light front wave functions (LF-LFWFs) of the rho and J/psi mesons, for the first time from the Dyson-Schwinger and Bethe-Salpeter equations approach. A unique advantage of this method is that it renders a direct extraction of LF-LFWFs in presence of a number of higher Fock-states. Modulated by the current quark mass and driven by the dynamical chiral symmetry breaking, we find the rho and J/psi LF-LFWFs different in profile, i.e., the former are broadly distributed in x (the longitudinal light-cone momentum fraction of meson carried by quark) while the latter are narrow. Moreover, the rho LF LFWFs contribute less than 50% to the total Fock-state normalization, suggesting considerable higher Fock-states in rho. We then use these LF-LFWFs to study the diffractive rho and J/psi electroproduction within the dipole picture. The calculated cross section shows general agreement with HERA data, except for growing discrepancy in rho production at low photon virtuality.