  The protoplanetary disk around the GGTau A binary system is so far one of the
most studied young circumbinary disk. Observations of the dust continuum
emission at sub-mm/mm wavelengths detected a dust ring located between 200AU
and 300AU from the center of mass of the system. If the disk and the binary
orbit are coplanar, given the observed projected separation of the stars in the
binary system, the classical theory of tidal interaction between a binary
system and its circumbinary disk predicts a truncation radius which is
significantly smaller than the measured inner radius of the mm-sized dust ring.
We investigate the origin of this dust ring structure in the GG Tau A disk,
test whether the interaction between the binary and the disk can produce a dust
trap at the location of the observed ring, and discuss an alternative scenario
which invokes a misalignment between the disk and the stellar orbital planes.
We run a set of hydrodynamical simulations for an orbit consistent with the
astrometric solutions for the GG Tau A stellar proper motions, and for
different disk temperature and viscosities. We then apply a dust evolution
model in post-processing in order to to retrieve the distribution of mm-sized
grains. Comparing models and observations, we show that, if the binary orbit
and the disk were coplanar,the tidal truncation of the circumbinary disk would
occur at a radius that is too small compared to the inner edge inferred by the
dust observations, and that the pressure bump and the dust ring in the models
would be located at <150AU from the center of mass of the stellar system. This
shows that the GG Tau A disk cannot be coplanar with the binary orbital plane.
We also discuss the viability of the misaligned disk scenario, suggesting that
in order for dust trapping to occur at the observed radius, the disk and
orbital plane must be misaligned by an angle of about 25 degrees.
