Constraints on Multi-Field Inflation from the BOSS Galaxy Survey

TL;DR

This paper uses BOSS galaxy survey data to constrain local primordial non-Gaussianity, finding no evidence for it and demonstrating the potential for future surveys to improve these constraints.

Contribution

It provides the first comprehensive analysis of LPNG constraints from BOSS galaxy clustering data using full perturbation theory models and optimal estimators.

Findings

Constraint on $f_{NL}^{local}$ is $-33 \, ext{±}\, 28$ at 68% CL.

Adding bispectrum data improves constraints by 20%.

Results establish a baseline for future larger-volume surveys.

Abstract

We use redshift-space galaxy clustering data from the BOSS survey to constrain local primordial non-Gaussianity (LPNG). This is of particular importance due to the consistency relations, which imply that a detection of LPNG would rule out all single-field inflationary models. Our constraints are based on the consistently analyzed redshift-space galaxy power spectra and bispectra, extracted from the public BOSS data with optimal window-free estimators. We use a complete perturbation theory model including all one-loop power spectrum corrections generated by LPNG. Our constraint on the amplitude of the local non-Gaussian shape is $f_{\rm NL}^{\rm local}=-33\pm 28$ at 68\%\,CL, yielding no evidence for primordial non-Gaussianity. The addition of the bispectrum tightens the $f_{\rm NL}^{\rm local}$ constraints from BOSS by $20\%$, and allows breaking of degeneracies with non-Gaussian galaxy bias. These results set the stage for the analysis of future surveys, whose larger volumes will yield significantly tighter constraints on LPNG.