K-mouflage Imprints on Cosmological Observables and Data Constraints
  We investigate cosmological constraints on K-mouflage models of modified
gravity. We consider two scenarios: one where the background evolution is free
to deviate from $\Lambda$CDM (K-mouflage) and another one which reproduces a
$\Lambda$CDM expansion (K-mimic), implementing both of them into the EFTCAMB
code. We discuss the main observational signatures of these models and we
compare their cosmological predictions to different datasets, including CMB,
CMB lensing, SNIa and different galaxy catalogues. We argue about the
possibility of relieving the $H_0$ and weak lensing tensions within these
models, finding that K-mouflage scenarios effectively ease the tension on the
Hubble Constant. Our final 95\% C.L. bounds on the $\epsilon_{2,0}$ parameter
that measures the overall departure from $\Lambda$CDM (corresponding to
$\epsilon_{2,0}=0$) are $-0.04\leq \epsilon_{2,0} <0$ for K-mouflage and $0<
\epsilon_{2,0} <0.002$ for K-mimic. In the former case the main constraining
power comes from changes in the background expansion history, while in the
latter case the model is strongly constrained by measurements of the amplitude
of matter perturbations. The sensitivity of these cosmological constraints
closely matches that of solar system probes. We show that these constraints
could be significantly tightened with future ideal probes like CORE.
