Constraining disformal couplings with Redshift Space Distortion
  We study a quintessence model for which the scalar field is disformally
coupled to dark matter. The background mimics the LCDM cosmological evolution
and the quintessence potential is not specified. A disformal effect due to the
quintessential mass is seen in the growth rate of the cosmological structure on
large scales. The disformal parameter renders no appreciable effect on the
evolution of the total matter perturbation. An analysis of the conformal
parameter and quintessential mass is investigated using the Redshift Space
Distortion data to find the best-fit values that might explain the well-known
sigma 8 tension. The best fit of the parameters indicates that the RSD data
prefers the model to behave conformally.
