The (not so) squeezed limit of the primordial 3-point function
- Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151, Trieste (Italy)
- Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States)
- Institut de Ciències del Cosmos (ICC), Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona (Spain)
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{sub L}/k{sub S}){sup 2}. This implies that a detection of a bispectrum signal going as 1/k{sub L}{sup 2} in the squeezed limit, that is suppressed only by one power of k{sub 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.
- OSTI ID:
- 22280274
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2011, Issue 11; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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