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arXiv · 1201.5375

A New Window on Primordial non-Gaussianity

Enrico Pajer·Matias Zaldarriaga
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Abstract

We know very little about primordial curvature perturbations on scales smaller than about a Mpc. Measurements of the mu-type distortion of the CMB spectrum provide the unique opportunity to probe these scales over the unexplored range from 50 to 10^4 Mpc^-1. This is a very clean probe, in that it relies only on well-understood linear evolution. We point out that correlations between mu-distortion and temperature anisotropies can be used to test Gaussianity at these very small scales. In particular the mu-T cross correlation is proportional to the very squeezed limit of the primordial bispectrum and hence measures fNL^loc, while mu-mu is proportional to the primordial trispectrum and measures tauNL. We present a Fisher matrix forecast of the observational constraints.

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Enrico Pajer, Matias Zaldarriaga. 2012-01-25. A New Window on Primordial non-Gaussianity. https://doi.org/10.1103/physrevlett.109.021302

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