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Abstract

We present the cosmological constraints from analyzing higher-order galaxy clustering on small nonlinear scales. We use SimBIG, a forward modeling framework for galaxy clustering analyses that employs simulation-based inference to perform highly efficient cosmological inference using normalizing flows. It leverages the predictive power of high-fidelity simulations and robustly extracts cosmological information from regimes inaccessible with current standard analyses. In this work, we apply SimBIG to a subset of the BOSS galaxy sample and analyze the redshift-space bispectrum monopole, B0 & eth;k1, k2, k3 & THORN;, to kmax = 0.5 h/Mpc. We achieve 1 sigma constraints of Omega m = 0.293 & thorn;0.027-0.027 and sigma 8 = 0.783 & thorn;0.040 than 1.2 and 2.4x tighter than constraints from standard power spectrum analyses of the same dataset. We also derive 1.4, 1.4, 1.7x tighter constraints on Omega b, h, ns. This improvement comes from additional cosmological information in higher-order clustering on nonlinear scales and, for sigma 8, is equivalent to the gain expected from a standard analysis on a similar to 4x larger galaxy sample. Even with our BOSS subsample, which only spans 10% of the full BOSS volume, we derive competitive constraints on the growth of structure: -0.053. Our constraint is consistent with results from both cosmic microwave background and weak lensing. Combined with a cob prior from big bang nucleosynthesis, we also derive a constraint on -1.8 km s-1 Mpc-1 that is consistent with early Universe constraints.