On hilltop and brane inflation after Planck
2019; Institute of Physics; Volume: 2019; Issue: 09 Linguagem: Inglês
10.1088/1475-7516/2019/09/030
ISSN1475-7516
Autores Tópico(s)Galaxies: Formation, Evolution, Phenomena
ResumoHilltop inflation models are often described by potentials V = V0 (1−ϕn/mn+... ). The omitted terms indicated by ellipsis do not affect inflation for m ≲ 1, but the most popular models with n = 2 and 4 for m ≲ 1 are ruled out observationally. Meanwhile in the large m limit the results of the calculations of the tensor to scalar ratio r in the models with V = V0 (1−ϕn/mn), for all n, converge to r = 4/N ≲ 0.07, as in chaotic inflation with V ∼ ϕ, suggesting a reasonably good fit to the Planck data. We show, however, that this is an artifact related to the inconsistency of the model V = V0 (1−ϕn/mn) at ϕ > m. Consistent generalizations of this model in the large m limit typically lead to a much greater value r = 8/N, which negatively affects the observational status of hilltop inflation. Similar results are valid for D-brane inflation with V = V0(1−mn/ϕn), but consistent generalizations of D-brane inflation models may successfully complement α-attractors in describing most of the area in the (ns, r) space favored by Planck 2018.
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