On the Trispectrum of Galileon Inflation
  We present a detailed study of the trispectrum of the curvature perturbation
generated within a stable, well defined and predictive theory which comprises
an inflationary phase. In this model the usual shift symmetry is enhanced up to
the so-called Galileon symmetry. The appeal of this type of theories rests on
being unitary and stable under quantum corrections. Furthermore, in the
specific model under consideration here, these properties have been shown to
approximately hold in realistic scenarios which account for curved spacetime
and the coupling with gravity. In the literature, the analysis of the
bispectrum of the curvature perturbation for this theory revealed non-Gaussian
features which are shared by a number of inflationary models, including stable
ones. It is therefore both timely and useful to investigate further and turn to
observables such as the trispectrum. We find that, in a number of specific
momenta configurations, the trispectrum shape-functions present strikingly
different features as compared to, for example, the entire class of the
so-called $P(X,\phi)$ inflationary models.
