Arbitrating the <i>S</i> 8 discrepancy with growth rate measurements from redshift-space distortions

Abstract

ABSTRACT Within the Lambda cold dark matter (ΛCDM) model, measurements from recent cosmic microwave background (CMB) and weak lensing (WL) surveys have uncovered a ∼3σ disagreement in the inferred value of the parameter $S_8 \equiv \sigma _8\sqrt{\Omega _\mathrm{ m}/0.3}$, quantifying the amplitude of late-time matter fluctuations. Before questioning whether the S8 discrepancy calls for new physics, it is important to assess the view of measurements other than CMB and WL ones on the discrepancy. Here, we examine the role of measurements of the growth rate f(z) in arbitrating the S8 discrepancy, considering measurements of fσ8(z) from redshift-space distortions (RSDs). Our baseline analysis combines RSD measurements with geometrical measurements from baryon acoustic oscillations (BAO) and T