General formula for the running of local fNL

TL;DR

This paper derives a general formula for the scale dependence of local fNL in multi-field inflation models, highlighting the role of the curved field space metric and its curvature in influencing observable non-Gaussianity.

Contribution

It introduces a comprehensive formula accounting for the field space curvature's effect on fNL scale dependence in multi-field inflation.

Findings

Field space curvature affects fNL scale dependence.

The scale dependence could be detectable with future observations.

The formula generalizes previous models by including arbitrary field space metrics.

Abstract

We compute the scale dependence of fNL for models of multi-field inflation, allowing for an arbitrary field space metric. We show that, in addition to multi-field effects and self interactions, the curved field space metric provides another source of scale dependence, which arises from the field-space Riemann curvature tensor and its derivatives. The scale dependence may be detectable within the near future if the amplitude of fNL is not too far from the current observational bounds.