Quantifying the $S_8$ tension with the Redshift Space Distortion data
  set
  One problem of the $\Lambda$CDM model is the tension between the $S_8$ found
in Cosmic Microwave Background (CMB) experiments and the smaller one obtained
from large-scale observations in the late Universe. The $\sigma_8$ quantifies
the relatively high level of clustering. Bayesian Analysis of the Redshift
Space Distortion (RSD) selected data set yields: $S_8 =
0.700^{+0.038}_{-0.037}$. The fit has $3\sigma$ tension with the Planck 2018
results. With Gaussian processes method a model-independent reconstructions of
the growth history of matter in-homogeneity is studied. The fit yields $S_8 =
0.707^{+0.085}_{-0.085}, 0.701^{+0.089}_{-0.089}$, and $
0.731^{+0.063}_{-0.062}$ for different kernels. The tension reduces and being
smaller then $1.5\, \sigma$. With future measurements the tension may be
reduced, but the possibility the tension is real is a plausible situation.
