Full trispectrum in single field DBI inflation

Frederico Arroja, Shuntaro Mizuno, Kazuya Koyama, Takahiro Tanaka

Research output: Contribution to journalArticle

76 Citations (Scopus)

Abstract

We compute the tree-level connected four-point function of the primordial curvature perturbation for a fairly general minimally coupled single field inflationary model, where the inflaton's Lagrangian is a general function of the scalar field and its first derivatives. This model includes K inflation and DBI inflation as particular cases. We show that, at the leading order in the slow-roll expansion and in the small sound speed limit, there are two important tree-level diagrams for the trispectrum. One is a diagram where a scalar mode is exchanged and the other is a diagram where the interaction occurs at a point, i.e. a contact interaction diagram. The scalar exchange contribution is comparable to the contact interaction contribution. For the DBI-inflation model, in the so-called equilateral configuration, the scalar exchange trispectrum is maximized when the angles between the four momentum vectors are equal and in this case the amplitude of the trispectrum from the scalar exchange is 1 order of magnitude higher than the contact interaction trispectrum.

Original languageEnglish
Article number043527
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume80
Issue number4
DOIs
Publication statusPublished - 2009 Aug 25
Externally publishedYes

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scalars
diagrams
electric contacts
interactions
curvature
momentum
perturbation
expansion
acoustics
configurations

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

Full trispectrum in single field DBI inflation. / Arroja, Frederico; Mizuno, Shuntaro; Koyama, Kazuya; Tanaka, Takahiro.

In: Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol. 80, No. 4, 043527, 25.08.2009.

Research output: Contribution to journalArticle

Arroja, Frederico ; Mizuno, Shuntaro ; Koyama, Kazuya ; Tanaka, Takahiro. / Full trispectrum in single field DBI inflation. In: Physical Review D - Particles, Fields, Gravitation and Cosmology. 2009 ; Vol. 80, No. 4.
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