Mass of nonrelativistic meson from leading twist distribution amplitudes

In this paper distribution amplitudes of pseudoscalar and vector nonrelativistic mesons are considered. Using equations of motion for the distribution amplitudes, it is derived relations which allow one to calculate the masses of nonrelativistic pseudoscalar and vector meson if the leading twist distribution amplitudes are known. These relations can be also rewritten as relations between the masses of nonrelativistic mesons and infinite series of QCD operators, what can be considered as an exact version of Gremm-Kapustin relation in NRQCD.Comment: 4 page

Many-body effects in graphene beyond the Dirac model with Coulomb interaction

This paper is devoted to development of perturbation theory for studying the properties of graphene sheet of finite size, at nonzero temperature and chemical potential. The perturbation theory is based on the tight-binding Hamiltonian and arbitrary interaction potential between electrons, which is considered as a perturbation. One-loop corrections to the electron propagator and to the interaction potential at nonzero temperature and chemical potential are calculated. One-loop formulas for the energy spectrum of electrons in graphene, for the renormalized Fermi velocity and also for the dielectric permittivity are derived.Comment: 11 pages, 11 figure

The study of leading twist light cone wave functions of J/Psi meson

This paper is devoted to the study of leading twist light cone wave functions of J/Psi meson. The moments of these wave functions have been calculated within three approaches: potential models, nonrelativistic QCD and QCD sum rules. Using the results obtained within these approaches the models for the light cone wave functions of leading twist have been proposed. Similarly to the wave function of eta_c meson the leading twist light cone wave functions of J/Psi meson have very interesting properties at scales greater than 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 true leading twist light cone wave functions of J/Psi meson.Comment: 10 pages, 1 figur