Equilateral Non-Gaussianity and New Physics on the Horizon

By D. Baumann, D. Green. 2011

213 citations recorded by the source corpus.

We examine the effective theory of single-field inflation in the limit where the scalar perturbations propagate with a small speed of sound. In this case the non-linearly realized time-translation symmetry of the Lagrangian implies large interactions, giving rise to primordial non-Gaussianities. When the non-Gaussianities are measurable, these interactions will become strongly coupled unless new physics appears close to the Hubble scale. Due to its proximity to the Hubble scale, the new physics is not necessarily decoupled from inflationary observables and can potentially affect the predictions of the model. To understand the types of corrections that may arise, we construct weakly-coupled completions of the theory and study their observational signatures.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/366c9dc240bfdc0ff34a52f6ed3003074d7ed8b8

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Citations in the corpus

CMB-S4 Science Case, Reference Design, and Project Plan (2019, background): “In single-field inflation, the amplitude of the nonGaussianity typically suggests a new energy scale, M , such that f equil NL ∝ A −1/2 s (H/M) [96, 106]; at this energy scale self-interactions become strongly coupled and current limits on non-Gaussianity [17] translate into M > O(10)H.”
On soft limits of inflationary correlation functions (2012, unknown): “For the specific mixing term we consider, Hmix = −ρθ̇σ, an effective mass of order ρ is generated for σ [24, 57].”
Inflation, Cosmic Perturbations and Non-Gaussianities (2013, background): “[153] D.”
Effective theories of single field inflation when heavy fields matter (2012, background): “[1, 25] for a discussion on this) and therefore we may demand that”
Non-Gaussianity as a particle detector (2016, unknown): “where f4 π ≡ 2M2 pl|Ḣ|cπ is the symmetry breaking scale [31].”
Inflation and String Theory (2014, background): “In the limit of observable non-Gaussianity, the theory of the fluctuations becomes strongly coupled below the symmetry-breaking scale φ̇ [265], and must therefore be UV-completed below φ̇.”
Effective field theory of cosmological perturbations (2013, background): “For an exhaustive discussion of all the scales that are relevant during inflation we refer the reader to [17].”
Signature of supersymmetry from the early universe (2011, methodology): “2 Naturalness of Small Sound Speed Is the hierarchy M4 2 M2 pl|Ḣ|—and hence cs 1—natural? Before we address this question, we digress briefly to review our prior work on the subject [40].”