Higher order non-linear parameters with PLANCK

TL;DR

This paper analyzes the impact of higher order non-linear parameters on lower order ones via loop corrections, showing stability of tree-level results and discussing observational constraints in inflation models.

Contribution

It provides explicit two-loop calculations of non-linear parameter corrections and discusses their implications for observational constraints in single-source and multi-source inflation.

Findings

Tree contributions are stable against loop effects in most cases.

Loop corrections can impose limits on higher order non-linear parameters.

Observational constraints on parameters like fNL and tauNL are affected by loop effects.

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.