The BOSS bispectrum analysis at one loop from the Effective Field Theory of Large-Scale Structure

TL;DR

This paper employs the Effective Field Theory of Large-Scale Structure to analyze BOSS data, incorporating one-loop and tree-level predictions for the power spectrum and bispectrum, leading to improved parameter constraints and validation against simulations.

Contribution

It introduces a combined analysis of power spectrum and bispectrum using one-loop EFTofLSS predictions, reducing uncertainties and demonstrating consistency with Planck data.

Findings

Reduced error bars on cosmological parameters by up to 30%

Achieved consistent results with Planck measurements

Validated analysis pipeline against simulations

Abstract

We analyze the BOSS power spectrum monopole and quadrupole, and the bispectrum monopole and quadrupole data, using the predictions from the Effective Field Theory of Large-Scale Structure (EFTofLSS). Specifically, we use the one loop prediction for the power spectrum and the bispectrum monopole, and the tree level for the bispectrum quadrupole. After validating our pipeline against numerical simulations as well as checking for several internal consistencies, we apply it to the observational data. We find that analyzing the bispectrum monopole to higher wavenumbers thanks to the one-loop prediction, as well as the addition of the tree-level quadrupole, significantly reduces the error bars with respect to our original analysis of the power spectrum at one loop and bispectrum monopole at tree level. After fixing the spectral tilt to Planck preferred value and using a Big Bang Nucleosynthesis prior, we measure $\sigma_8=0.794\pm 0.037$, $h = 0.692\pm 0.011$, and $\Omega_m = 0.311\pm 0.010$ to about $4.7\%$, $1.6\%$, and $3.2\%$, at $68\%$ CL, respectively. This represents an error bar reduction with respect to the power spectrum-only analysis of about $30\%$, $18\%$, and $13\%$ respectively. Remarkably, the results are compatible with the ones obtained with a power-spectrum-only analysis, showing the power of the EFTofLSS in simultaneously predicting several observables. We find no tension with Planck.