Constraints on Kinetically Modified Inflation from WMAP5

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dc.creatorLorenz, Larissa
dc.creatorMartin, Jerome
dc.creatorRingeval, Christophe
dc.date2008-07-15
dc.date.accessioned2026-07-07T11:44:50Z
dc.date.available2026-07-07T11:44:50Z
dc.descriptionSingle field inflationary models with a non-minimal kinetic term (also called k-inflationary models) can be characterised by the so-called sound flow functions, which complete the usual Hubble flow hierarchy. These parameters appear in the primordial power spectra of cosmological perturbations at leading order and, therefore, affect the resulting Cosmic Microwave Background (CMB) anisotropies. Using the fifth year Wilkinson Microwave Anisotropy Probe (WMAP5) data, we derive the marginalised posterior probability distributions for both the sound and Hubble flow parameters. In contrast to the standard situation, these parameters remain separately unbounded, and notably there is no longer any upper limit on epsilon_1, the first Hubble flow function. Only special combinations of these parameters, corresponding to the spectral index and tensor-to-scalar ratio observables, are actually constrained by the data. The energy scale of k-inflation is nevertheless limited from above to Hinf/mpl < 6x10^(-6) at two-sigma level. Moreover, for the sub-class of Dirac-Born-Infeld models, by considering the non-gaussianity bounds on the sound speed, we find a weak limit epsilon_1 < 0.08 at 95% confidence level.
dc.description7 pages, 6 figures, uses RevTeX
dc.identifierhttps://arxiv.org/abs/0807.2414
dc.identifierhttp://arxiv.org/abs/0807.2414
dc.identifierPhys.Rev.D78:063543,2008
dc.identifierdoi:10.1103/PhysRevD.78.063543
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/201689
dc.subjectAstrophysics
dc.subjectGeneral Relativity and Quantum Cosmology
dc.subjectHigh Energy Physics - Phenomenology
dc.subjectHigh Energy Physics - Theory
dc.titleConstraints on Kinetically Modified Inflation from WMAP5
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