$${\sigma }_{8}$$ Tension. Is Gravity Getting Weaker at Low z? Observational Evidence and Theoretical Implications

  title={\$\$\{\sigma \}\_\{8\}\$\$ Tension. Is Gravity Getting Weaker at Low z? Observational Evidence and Theoretical Implications},
  author={Lavrentios Kazantzidis and Leandros Perivolaropoulos},
  journal={Modified Gravity and Cosmology},
Dynamical observational probes of the growth of density perturbations indicate that gravity may be getting weaker at low redshifts $z$. This evidence is at about $2-3\sigma$ level and comes mainly from weak lensing data that measure the parameter $S_8=\sigma_8 \sqrt{\Omega_{0m}/0.3}$ and redshift space distortion data that measure the growth rate times the amplitude of the linear power spectrum parameter $f\sigma_8 (z)$. The measured $f\sigma_8$ appears to be lower than the prediction of… 
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