The study of leading twist light cone wave function of \eta_c meson

This paper is devoted to the study of leading twist light cone wave function of $\eta_c$ meson. The moments of this wave function have been calculated within three approaches: potential models, nonrelativistic QCD and QCD sum rules. Using the results obtained within these approaches the model for the light cone wave function of leading twist has been proposed. Being scale dependent light cone wave function has very interesting properties at scales $\mu> m_c$: improvement of the accuracy of the model, appearance of relativistic tail and violation of nonrelativistic QCD velocity scaling rules. The last two properties are the properties of real leading twist light cone wave function of $\eta_c$ meson.