The cosmological analysis of DES 3×2pt data from the Effective Field Theory of Large-Scale Structure

We analyze the Dark Energy Survey (DES) Year 3 data using predictions from the Effective Field Theory of Large-Scale Structure (EFTofLSS). Specifically, we fit three two-point observables (3×2pt), galaxy clustering, galaxy-galaxy lensing, and cosmic shear, using the one-loop expressions for the projected angular correlation functions. We validate our pipeline against numerical simulations and we check for several internal consistencies before applying it to the observational data. Fixing the spectral tilt and the baryons abundance, we measure S8 = 0.833 ± 0.032, Ωm = 0.272 ± 0.022, and h = 0.773 ± 0.049, to about 3.8%, 8.1%, and 6.3%, at 68%CL, respectively. Our results are consistent at the ∼ 1.5–2σ level with those from Planck and the BOSS full-shape analyses, as well as with those from DES collaboration 3×2pt analysis combined with a Big-Bang Nucleosynthesis prior and a Planck prior on ns. The difference in the posteriors compared to the DES collaboration results, obtained from the same dataset combinations, highlights the impact of modeling, scale cuts, and choice of prior. The theory code and likelihood used for our analyses, PyFowl, is made publicly available.