Galilean symmetry in the effective theory of inflation: new shapes of nonGaussianity
Abstract
We study the consequences of imposing an approximate Galilean symmetry on the Effective Theory of Inflation, the theory of small perturbations around the inflationary background. This approach allows us to study the effect of operators with two derivatives on each field, which can be the leading interactions due to nonrenormalization properties of the Galilean Lagrangian. In this case cubic nonGaussianities are given by three independent operators, containing up to six derivatives, two with a shape close to equilateral and one peaking on flattened isosceles triangles. The fourpoint function is larger than in models with small speed of sound and potentially observable with the Planck satellite.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 February 2011
 DOI:
 10.1088/14757516/2011/02/006
 arXiv:
 arXiv:1011.3004
 Bibcode:
 2011JCAP...02..006C
 Keywords:

 High Energy Physics  Theory;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 23 pages, 6 figures. v2: minor changes to match JCAP published version