We propose a method to calculate the qqΛβ light front wave functions
(LFWFs) of photon at low-virtuality, i.e., the light front amplitude of
Ξ³ββqqΛβ at low Q2, based on a light front projection
approach. We exemplify this method using a contact interaction model within
Dyson-Schwinger equations formalism and obtain the nonperturbative photon
qqΛβ LFWFs. In this case, we find the nonperturbative effects are encoded
in the enhanced quark mass and a dressing function of covariant quark-photon
vertex, as compared to the leading order quantum electrodynamics photon
qqΛβ LFWFs. We then use nonperturbative-effect modified photon qqΛβ
LFWFs to study the inclusive deep inelastic scattering HERA data in the
framework of the color dipole model. The results demonstrate that the
theoretical description of data at low Q2 can be significantly improved once
the nonperturbative corrections are included in the photon LFWFs.Comment: 11 pages, 4 figure