204 research outputs found
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
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
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
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