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arXiv · 1106.1462

The (not so) squeezed limit of the primordial 3-point function

Paolo Creminelli·Guido D'Amico·Marcello Musso·Jorge Noreña
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Abstract

We prove that, in a generic single-field model, the consistency relation for the 3-point function in the squeezed limit receives corrections that vanish quadratically in the ratio of the momenta, i.e. as (k_L/k_S)^2. This implies that a detection of a bispectrum signal going as 1/k_L^2 in the squeezed limit, that is suppressed only by one power of k_L compared with the local shape, would rule out all single-field models. The absence of this kind of terms in the bispectrum holds also for multifield models, but only if all the fields have a mass much smaller than H. The detection of any scale dependence of the bias, for scales much larger than the size of the haloes, would disprove all single-field models. We comment on the regime of squeezing that can be probed by realistic surveys.

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Paolo Creminelli, Guido D'Amico, Marcello Musso, Jorge Noreña. 2011-11-15. The (not so) squeezed limit of the primordial 3-point function. https://doi.org/10.1088/1475-7516%2F2011%2F11%2F038

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