{
  "id": "1108.3839",
  "version": "v2",
  "published": "2011-08-18T20:00:11.000Z",
  "updated": "2011-10-24T09:23:03.000Z",
  "title": "Decoding the bispectrum of single-field inflation",
  "authors": [
    "Raquel H. Ribeiro",
    "David Seery"
  ],
  "comment": "v1: 25 pages, including tables, an appendix and references. v2: minor clarifications about the lowest-order consistency relations; matches version published in JCAP",
  "journal": "JCAP 10 (2011) 027",
  "doi": "10.1088/1475-7516/2011/10/027",
  "categories": [
    "astro-ph.CO",
    "hep-ph",
    "hep-th"
  ],
  "abstract": "Galileon fields arise naturally from the decoupling limit of massive gravities, and possess special self-interactions which are protected by a spacetime generalization of Galilean symmetry. We briefly revisit the inflationary phenomenology of Galileon theories. Working from recent computations of the fluctuation Lagrangian to cubic order in the most general model with second-order equations of motion, we show that a distinct shape is present but with suppressed amplitude. A similar shape has been found in other higher-derivative models. It may be visible in a theory tuned to suppress the leading-order shapes, or if the overall bispectrum has large amplitude. Using a partial-wave expansion of the bispectrum, we suggest a possible origin for the frequent appearance of this shape. It follows that models with very disparate microphysics can produce very similar bispectra. We argue that it may be more profitable to distinguish these models by searching for relations between the amplitudes of these common shapes. We illustrate this method using the example of DBI and k-inflation.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2011-10-24T09:23:03.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "single-field inflation",
      "galileon fields arise",
      "possess special self-interactions",
      "similar bispectra",
      "disparate microphysics"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "IOP",
      "journal": "Journal of Cosmology and Astro-Particle Physics",
      "year": 2011,
      "month": "Oct",
      "volume": 2011,
      "number": 10,
      "pages": "027"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 25,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 924429,
      "adsabs": "2011JCAP...10..027R"
    }
  }
}