Higher order non-linear parameters with PLANCK

Abstract

We investigate how higher order non-linear parameters affect lower order ones through loop effects. We calculate the loop corrections up to two-loops and explicitly show that the tree contribution is stable against loop terms in most cases. We argue that, nevertheless, observational constraints on non-linear parameters such as fNL and tauNL can also give a limit even for higher order ones due to the loop contribution. We discuss these issues both for single-source and multi-source cases.

Comments: (v1) 25 pages, 12 figures; (v2) More clarifications, to appear in Physical Review D