Minimal Higgs inflation with an R2 term in Palatini gravity

Tommi Tenkanen
Phys. Rev. D 99, 063528 – Published 26 March 2019

Abstract

It has recently been suggested that the Standard Model Higgs boson could act as the inflaton while minimally coupled to gravity—given that the gravity sector is extended with an αR2 term and the underlying theory of gravity is of Palatini, rather than metric, type. In this paper, we revisit the idea and correct some shortcomings in earlier studies. We find that, in this setup, the Higgs can indeed act as the inflaton and that the tree-level predictions of the model for the spectral index and the tensor-to-scalar ratio are ns0.941, r0.3/(1+108α), respectively, for a typical number of e-folds, N=50, between horizon exit of the pivot scale k=0.05Mpc1 and the end of inflation. Even though the tensor-to-scalar ratio is suppressed compared to the usual minimally coupled case and can be made compatible with data for large enough α, the result for ns is in severe tension with the Planck results. We briefly discuss extensions of the model.

  • Figure
  • Received 9 February 2019

DOI:https://doi.org/10.1103/PhysRevD.99.063528

© 2019 American Physical Society

Physics Subject Headings (PhySH)

  1. Research Areas
  1. Physical Systems
Gravitation, Cosmology & AstrophysicsParticles & Fields

Authors & Affiliations

Tommi Tenkanen*

  • Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA

  • *ttenkan1@jhu.edu

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Issue

Vol. 99, Iss. 6 — 15 March 2019

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