Higgs-R^2 inflation - full slow-roll study at tree level

Vera-Maria Sofia Enckell, Kari Enqvist, Syksy Räsänen, Lumi-Pyry Wahlman

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Sammanfattning

We consider Higgs inflation with an α R2 term. It adds a new scalar degree of freedom, which leads to a two-field model of inflation. We do a complete slow-roll analysis of the three-dimensional parameter space of the R2 coefficient α, the non-minimal coupling ξ and the Higgs self-coupling λ. We find three classes of inflationary solutions, but only pure R2 and attractor solutions fit observations. We find that pure Higgs inflation is impossible when the R2 term is present regardless of how small α is. However, we can have Higgs-like inflation, where the amplitude of the perturbations does not depend on α and the predictions as a function of e-folds are the same as in Higgs inflation, although the inflationary trajectory is curved in field space. The spectral index is 0.939 < nR < 0.967, and constraining it to the observed range, the tensor-to-scalar ratio varies from 3.8×10−3 to the maximum allowed by observations, 0.079. Observational constraints on isocurvature perturbations contribute to these limits, whereas non-Gaussianity is automatically in the range allowed by observations.
Originalspråkengelska
ArtikelnummerArXiv:1812.08754
TidskriftJournal of Cosmology and Astroparticle Physics
Antal sidor17
ISSN1475-7516
DOI
StatusPublicerad - 20 jan 2020
MoE-publikationstypA1 Tidskriftsartikel-refererad

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