Remarks on the Starobinsky model of inflation and its descendants

Kehagias, Alexandros A.; Dizgah, Azadeh Moradinezhad; Riotto, Antonio

doi:10.1103/physrevd.89.043527

Cited by 191 publications

(256 citation statements)

References 49 publications

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“…However, in this case the pure Higgs sector of the SM must pass through a strong coupling below the inflationary and above the LHC scales. This automatically requires a UV completion by other degrees of freedom at intermediate scale (see for example [10]). Therefore, in those cases, this "Higgs" potential cannot be directly connected to the SM Higgs potential (for latest examples see [11,12]).…”

Section: Jcap12(2014)009mentioning

confidence: 99%

Self-unitarization of New Higgs Inflation and compatibility with Planck and BICEP2 data

Germani¹,

Watanabe²,

Wintergerst³

2014

J. Cosmol. Astropart. Phys.

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In this paper we show that the Germani-Kehagias model of Higgs inflation (or New Higgs Inflation), where the Higgs boson is kinetically non-minimally coupled to the Einstein tensor is in perfect compatibility with the latest Planck and BICEP2 data. Moreover, we show that the tension between the Planck and BICEP2 data can be relieved within the New Higgs inflation scenario by a negative running of the spectral index. Regarding the unitarity of the model, we argue that it is unitary throughout the evolution of the Universe. Weak couplings in the Higgs-Higgs and Higgs-graviton sectors are provided by a large background dependent cut-off scale during inflation. In the same regime, the W and Z gauge bosons acquire a very large mass, thus decouple. On the other hand, if they are also non-minimally coupled to the Higgs boson, their effective masses can be enormously reduced. In this case, the W and Z bosons are no longer decoupled. After inflation, the New Higgs model is well approximated by a quartic Galileon with a renormalizable potential. We argue that this can unitarily create the right conditions for inflation to eventually start.

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Section: Jcap12(2014)009mentioning

confidence: 99%

Self-unitarization of New Higgs Inflation and compatibility with Planck and BICEP2 data

Germani¹,

Watanabe²,

Wintergerst³

2014

J. Cosmol. Astropart. Phys.

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“…We also analyze the impact of the one-loop radiative corrections (RCs) [51] on our results and find that these can be kept under control provided that the relevant renormalization scale is conveniently chosen [52]. We, finally, show that the ultraviolet (UV) cut-off scale [53][54][55][56][57] in these models coincides with the Planck scale and so concerns regarding their naturalness can be safely eluded.…”

Section: Jhep11(2015)114mentioning

confidence: 99%

“…To show this, we extract the UV cut-off scale Λ UV of the effective theory following the systematic approach of ref. [57]. Let us first clarify that, although the expansions presented below about φ = M 1 are not valid [56] during HI, we consider the resulting Λ UV as the overall cut-off scale of the theory, since reheating is regarded as an unavoidable stage of the inflationary dynamics [57].…”

Section: Jhep11(2015)114mentioning

confidence: 99%

Shift symmetry and Higgs inflation in supergravity with observable gravitational waves

Lazarides¹,

Pallis²

2015

J. High Energ. Phys.

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Abstract:We demonstrate how to realize within supergravity a novel chaotic-type inflationary scenario driven by the radial parts of a conjugate pair of Higgs superfields causing the spontaneous breaking of a grand unified gauge symmetry at a scale assuming the value of the supersymmetric grand unification scale. The superpotential is uniquely determined at the renormalizable level by the gauge symmetry and a continuous R symmetry. We select two types of Kähler potentials, which respect these symmetries as well as an approximate shift symmetry. In particular, they include in a logarithm a dominant shift-symmetric term proportional to a parameter c − together with a small term violating this symmetry and characterized by a parameter c + . In both cases, imposing a lower bound on c − , inflation can be attained with subplanckian values of the original inflaton, while the corresponding effective theory respects perturbative unitarity for r ± = c + /c − ≤ 1. These inflationary models do not lead to overproduction of cosmic defects, are largely independent of the one-loop radiative corrections and accommodate, for natural values of r ± , observable gravitational waves consistently with all the current observational data. The inflaton mass is mostly confined in the range (3.7 − 8.1) × 10 10 GeV.

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“…For this reason, there has been a a renewed interest on the Starobinsky model, with particular emphasis on its supergravity extensions [5][6][7][8][9][10][11], along the lines originated in Refs. [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

The imaginary Starobinsky model

Ferrara

Kehagias

Riotto³

2014

Fortschritte der Physik

114

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The recent detection by the BICEP2 collaboration of a high level of tensor modes seems to exclude the Starobinsky model of inflation. In this paper we show that this conclusion can be avoided: one can embed the Starobinsky model in supergravity and identify the inflaton field with the imaginary (instead of the real) part of the chiral scalaron multiplet in its formulation. Once coupled to matter, the Starobinsky model may then become the chaotic quadratic model with shift symmetry during inflation and is in good agreement with the current data.

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Remarks on the Starobinsky model of inflation and its descendants

Cited by 191 publications

References 49 publications

Self-unitarization of New Higgs Inflation and compatibility with Planck and BICEP2 data

Self-unitarization of New Higgs Inflation and compatibility with Planck and BICEP2 data

Shift symmetry and Higgs inflation in supergravity with observable gravitational waves

The imaginary Starobinsky model

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