Biasing and the search for primordial non-Gaussianity beyond the local type

TL;DR

This paper investigates how large-scale structure surveys can detect and distinguish various types of primordial non-Gaussianity beyond the local form, highlighting the potential of multi-tracer techniques to improve sensitivity.

Contribution

It provides forecasts for detecting non-Gaussianity beyond the local type using galaxy/halo power spectra and explores the advantages of multi-tracer methods.

Findings

Multi-tracer technique enhances sensitivity for all non-Gaussianity types.

Significant improvements over Planck are possible for quasi-single field inflation.

Distinguishing non-Gaussianity from general bias models is feasible.

Abstract

Primordial non-Gaussianity encodes valuable information about the physics of inflation, including the spectrum of particles and interactions. Significant improvements in our understanding of non-Gaussanity beyond Planck require information from large-scale structure. The most promising approach to utilize this information comes from the scale-dependent bias of halos. For local non-Gaussanity, the improvements available are well studied but the potential for non-Gaussianity beyond the local type, including equilateral and quasi-single field inflation, is much less well understood. In this paper, we forecast the capabilities of large-scale structure surveys to detect general non-Gaussianity through galaxy/halo power spectra. We study how non-Gaussanity can be distinguished from a general biasing model and where the information is encoded. For quasi-single field inflation, significant improvements over Planck are possible in some regions of parameter space. We also show that the multi-tracer technique can significantly improve the sensitivity for all non-Gaussianity types, providing up to an order of magnitude improvement for equilateral non-Gaussianity over the single-tracer measurement.