We measure the smallscale clustering of the Data Release 16 extended Baryon Oscillation Spectroscopic Survey Luminous Red Galaxy sample, corrected for fibrecollisions using Pairwise Inverse Probability weights, which give unbiased clustering measurements on all scales. We fit to the monopole and quadrupole moments and to the projected correlation function over the separation range $760\, h^{1}{\rm Mpc}$ with a model based on the aemulus cosmological emulator to measure the growth rate of cosmic structure, parametrized by fσ8. We obtain a measurement of fσ8(z = 0.737) = 0.408 ± 0.038, which is 1.4σ lower than the value expected from 2018 Planck data for a flat ΛCDM model, and is more consistent with recent weaklensing measurements. The level of precision achieved is 1.7 times better than more standard measurements made using only the largescale modes of the same sample. We also fit to the data using the full range of scales $0.1\text{}60\, h^{1}{\rm Mpc}$ modelled by the aemulus cosmological emulator and find a 4.5σ tension in the amplitude of the halo velocity field with the Planck + ΛCDM model, driven by a mismatch on the nonlinear scales. This may not be cosmological in origin, and could be due to a breakdown in the Halo Occupation Distribution model used in the emulator. Finally, we perform a robust analysis of possible sources of systematics, including the effects of redshift uncertainty and incompleteness due to target selection that were not included in previous analyses fitting to clustering measurements on small scales.
 Award ID(s):
 1828315
 NSFPAR ID:
 10313044
 Date Published:
 Journal Name:
 Monthly Notices of the Royal Astronomical Society
 Volume:
 509
 Issue:
 2
 ISSN:
 00358711
 Format(s):
 Medium: X
 Sponsoring Org:
 National Science Foundation
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