1210.4478 (Sayantan Choudhury et al.)

Large non-Gaussianities from DBI Galileon and resolution of sensitivity problem    [PDF]

Sayantan Choudhury, Supratik Pal

We have studied primordial non-Gaussian features through bispectrum and trispectrum analysis from a model of potential driven DBI Galileon inflation originating from background supergravity and Gauss-Bonnet terms.We have explicitly shown the violation of the widely accepted Maldacena theorem and standard Suyama-Yamaguchi relation in squeezed limit configuration which leads to the resolution of the well-known sensitivity problem between the non-Gaussian parameters ($f_{NL},\tau_{NL},g_{NL}$) and tensor to scalar ratio($r$). Our analysis thus overcomes a generic drawback of the wide class of DBI inflationary models which was, of late, facing tension from observational ground.Hence large primordial non-Gaussianities can be obtained even from single field DBI Galileon and hence these class of models can be directly confronted with the forthcoming results of PLANCK.

View original: http://arxiv.org/abs/1210.4478