Consistency of effective field theory analyses of the BOSS power spectrum

We assess the robustness of A cold dark matter (ACDM) results from the full-shape analysis of BOSS power spectrum using the one-loop prediction of the effective field theory of large-scale structure (EFTofLSS). In former EFT analyses, the two public likelihoods PyBird and CLASS-PT lead to results in agreement only at the 1s level, which may appear unsatisfactory given that they are derived from the same BOSS dataset and the same theory model. To identify the origin of the difference, we perform a thorough comparison of the various analyses choices made between the two pipelines. We find that most of the difference can be attributed to the choices of prior on the EFT parameters, dubbed "West-coast" (WC) prior and "East-coast" (EC) prior, respectively associated to PyBird and CLASS-PT. In particular, because posteriors are non-Gaussian, projection effects from the marginalization over the EFT parameters shift the posterior mean of the cosmological parameters with respect to the maximum a posteriori up to similar to 1 sigma in the WC prior and up to similar to 2 sigma in the EC prior. Additionally, we quantify that maximum a posteriori cosmological parameters extracted from BOSS given the two prior choices are consistent at less than or similar to 1 sigma. The consistency improves to less than or similar to 0.4 sigma when doubling the width of both priors. While this reveals that current EFT analyses are subject to prior effects, we show that cosmological results obtained in combination with cosmic microwave background, or from forthcoming large-volume data, are less sensitive to those effects. In addition, we evaluate the impact on the cosmological constraints from various BOSS power-spectrum measurements. While we find broad agreements across all pre-reconstructed measurements considered (<0.6 sigma), we show that the two available BOSS post-reconstructed measurements in Fourier space, once combined with the EFT full-shape analysis, lead to discrepant Hubble parameter H-0 at similar to 0.9 sigma. Finally, given the various effects we discuss, we argue that the clustering amplitude s(8) measured with BOSS is not in statistical tension with that inferred from Planck under ACDM.