  Motivated by a number of recent experimental studies, we have carried out the
microscopic calculation of the quasiparticle self-energy and spectral function
in a doped graphene when a symmetry breaking of the sublattices is occurred.
Our systematic study is based on the many-body G$_0$W approach that is
established on the random phase approximation and on graphene's massive Dirac
equation continuum model. We report extensive calculations of both the real and
imaginary parts of the quasiparticle self-energy in the presence of a gap
opening. We also present results for spectral function, renormalized Fermi
velocity and band gap renormalization of massive Dirac Fermions over a broad
range of electron densities. We further show that the mass generating in
graphene washes out the plasmaron peak in spectral weight.
