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arXiv · 2106.02089

Natural Inflation After Planck 2018

Nina K. Stein·William H. Kinney
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Abstract

We calculate high-precision constraints on Natural Inflation relative to current observational constraints from Planck 2018 + BICEP/Keck(BK15) Polarization + BAO on $r$ and $n_S$, including post-inflationary history of the universe. We find that, for conventional post-inflationary dynamics, Natural Inflation with a cosine potential is disfavored at greater than 95\% confidence out by current data. If we assume protracted reheating characterized by $\overline{w}>1/3,$ Natural Inflation can be brought into agreement with current observational constraints. However, bringing unmodified Natural Inflation into the 68\% confidence region requires values of $T_{\mathrm{re}}$ below the scale of electroweak symmetry breaking. The addition of a SHOES prior on the Hubble Constant $H_0$ only worsens the fit.

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Nina K. Stein, William H. Kinney. 2021-06-14. Natural Inflation After Planck 2018. https://doi.org/10.1088/1475-7516%2F2022%2F01%2F022

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