Direct search for features in the primordial bispectrum
  We study features in the bispectrum of the primordial curvature perturbation
correlated with the reconstructed primordial power spectrum from the observed
cosmic microwave background temperature data. We first show how the bispectrum
can be completely specified in terms of the power spectrum and its first two
derivatives, valid for any configuration of interest. Then using a
model-independent reconstruction of the primordial power spectrum from the
Planck angular power spectrum of temperature anisotropies, we compute the
bispectrum in different triangular configurations. We find that in the squeezed
limit at k ~ 0.06/Mpc and k ~ 0.014/Mpc there are marginal 2sigma deviations
from the standard featureless bispectrum, which meanwhile is consistent with
the reconstructed bispectrum in the equilateral configuration.
