Direct search for features in the primordial bispectrum

Abstract

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.

(v1) 6 pages, 4 figures; (v2) improved results but conclusions not changed, to appear in Physics Letters B

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• Constraints on holographic multi-field inflation and models based on the Hamilton-Jacobi formalism
• Bayesian reconstruction of the inflaton's speed of sound using CMB data
• Robust predictions for an oscillatory bispectrum in Planck 2015 data from transient reductions in the speed of sound of the inflaton
• Consistency relations for sharp inflationary non-Gaussian features
• Effect of damped oscillations in the inflationary potential
• Correlated primordial spectra in effective theory of inflation
• Features in single field slow-roll inflation
• Shapes and features of the primordial bispectrum
• Scale invariance of the primordial tensor power spectrum
• Degeneracy in the spectrum and bispectrum among featured inflaton potentials
• Inflation Story: slow-roll and beyond
• Fermions in $(1+2)$-dimensions modified by nonminimal coupling and its applications to condensed matter physics
• Cross-tests of CMB features in the primordial spectra