Non-Gaussianity in The Einstein-Scalar-Gauss-Bonnet Gravity Cosmological Inflation Model.
Afiq Agung (a), Getbogi Hikmawan (a), Freddy Permana Zen (a*).

a) Theoretical High Energy Physics Group, Department of Physics, Faculty of Mathematics and Natural Science, Bandung Institute of Technology
Jalan Ganesha 10, Bandung 40132, Indonesia
*Corresponding Author: fpzen[at]itb.ac.id, fpzen[at]fi.itb.ac.id, and arsyman[at]gmail.com

Abstract

An inflationary model can be constrained by non-gaussian statistics as a parameter in the distribution of large scale structure, and in temperature fluctuations of the cosmic microwave background. Data on the cosmic microwave background from Planck (2015) are able to provide up-to-date constraints on the parameters controlling the degree of non-Gaussianity in certain inflationary models, thus supporting or not supporting the model. Setting the non-Gaussianity parameter investigated in this study can be a reference whether or not it is a good parameter in constraining cosmological inflation models.
This study attempts to examine the non-Gaussianity of the 3+1 dimensional Einstein-scalar-Gauss-Bonnet gravitational cosmological inflation model starting from random field statistics. The non-Gaussian signature generated by the model is quantified, and the parameters controlling the degree of non-Gaussianity are constrained using data observation of Planck (2015). The method used in investigating non-Gaussianity is the in-in formalism, applied after obtaining the 3-point of \zeta (constant density curvature perturbation) terms of the perturbation expansion to the third order. The 3-point correlation function helps to create a bispectrum used to investigate the non-gaussinity of the inflation model. The results of this study show that the model tested is the slow-roll pressed in the squeezed limit, because it has a dominant local shape function.

Keywords: Bispectrum, Einstein-scalar-Gauss-Bonnet, in-in Formalism, Non-Gaussianity.

Topic: PHYSICAL SCIENCES