  We analyze by exact Renormalization Group (RG) methods the infrared
properties of an effective model of graphene, in which two-dimensional massless
Dirac fermions propagating with a velocity smaller than the speed of light
interact with a three-dimensional quantum electromagnetic field. The fermionic
correlation functions are written as series in the running coupling constants,
with finite coefficients that admit explicit bounds at all orders. The
implementation of Ward Identities in the RG scheme implies that the effective
charges tend to a line of fixed points. At small momenta, the quasi-particle
weight tends to zero and the effective Fermi velocity tends to a finite value.
These limits are approached with a power law behavior characterized by
non-universal critical exponents.
