Observational constraints on assisted k-inflation
- Department of Physics, Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)
We study observational constraints on the assisted k-inflation models in which multiple scalar fields join an attractor characterized by an effective single field {phi}. This effective single-field system is described by the Lagrangian P=Xg(Y), where X is the kinetic energy of {phi}, {lambda} is a constant, and g is an arbitrary function in terms of Y=Xe{sup {lambda}{phi}}. Our analysis covers a wide variety of k-inflation models such as dilatonic ghost condensate, Dirac-Born-Infeld field, and tachyon, as well as the canonical field with an exponential potential. We place observational bounds on the parameters of each model from the WMAP 7yr data combined with baryon acoustic oscillations and the Hubble constant measurement. Using the observational constraints of the equilateral non-Gaussianity parameter f{sub NL}{sup equil}, we further restrict the allowed parameter space of dilatonic ghost condensate and Dirac-Born-Infeld models. We extend the analysis to more general models with several different choices of g(Y) and show that the models such as g(Y)=c{sub 0}+c{sub p}Y{sup p} (p{>=}3) are excluded by the joint data analysis of the scalar/tensor spectra and primordial non-Gaussianities.
- OSTI ID:
- 21502565
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 83, Issue 10; Other Information: DOI: 10.1103/PhysRevD.83.103522; (c) 2011 American Institute of Physics; ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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