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Large slow-roll corrections to the bispectrum of noncanonical inflation

journal contribution
posted on 2023-06-07, 23:55 authored by Clare Burrage, Raquel H Ribeiro, David SeeryDavid Seery
Nongaussian statistics are a powerful discriminant between inflationary models, particularly those with noncanonical kinetic terms. Focusing on theories where the Lagrangian is an arbitrary Lorentz-invariant function of a scalar field and its first derivatives, we review and extend the calculation of the observable three-point function. We compute the "next-order" slow-roll corrections to the bispectrum in closed form, and obtain quantitative estimates of their magnitude in DBI and power-law k-inflation. In the DBI case our results enable us to estimate corrections from the shape of the potential and the warp factor: these can be of order several tens of percent. We track the possible sources of large logarithms which can spoil ordinary perturbation theory, and use them to obtain a general formula for the scale dependence of the bispectrum. Our result satisfies the next-order version of Maldacena's consistency condition and an equivalent consistency condition for the scale dependence. We identify a new bispectrum shape available at next-order, which is similar to a shape encountered in Galileon models. If fNL is sufficiently large this shape may be independently detectable.

History

Publication status

  • Published

Journal

Journal of Cosmology and Astroparticle Physics

ISSN

1475-7516

Issue

07

Volume

2011

Page range

032

Department affiliated with

  • Physics and Astronomy Publications

Notes

Author list in alphabetical order

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2012-02-06

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