Full trispectrum in single field DBI inflation

Journal Article · Sat Aug 15 04:00:00 EDT 2009 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.80.043527· OSTI ID:21322455

Arroja, Frederico; Tanaka, Takahiro ^[1]; Mizuno, Shuntaro ^[2]; Koyama, Kazuya ^[3]

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1. Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)
2. School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)
3. Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 2EG (United Kingdom)

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.

• OSTI ID: 21322455
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 4 Vol. 80; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMPLITUDES
COMPUTERIZED SIMULATION
CONFIGURATION
DISTURBANCES
EXPANSION
INTERACTIONS
LAGRANGIAN FUNCTION
PERTURBATION THEORY
SCALAR FIELDS
SOUND WAVES
SPEED LIMIT