On non-Gaussianities in single-field inflation

We study the impact of higher dimension operators in the inflaton Lagrangian on the non-Gaussianity of the scalar spectrum. These terms can strongly enhance the effect without spoiling slow-roll, though it is difficult to exceed f(NL)similar to1, because the scale which suppresses the operators cannot be too low, if we want the effective field theory description to make sense. In particular we explicitly calculate the three-point function given by an higher derivative interaction of the form (delphi)(4), which is expected to give the most important contribution. The angular dependence of the result turns out to be quite different from the minimal case without higher dimension operators.