Higher neutrino mass allowed if Cold Dark Matter and Dark Energy are coupled

Cosmological limits on neutrino masses are softened, by more than a factor 2, if Cold Dark Matter (CDM) and Dark Energy (DE) are coupled. In turn, a neutrino mass yielding $Omega_ u$ up to $sim0.20$ allows coupling levels $beta simeq 0.15, $ or more,already easing the coincidence problem. The coupling, in fact, displaces both $P(k)$ and $C_l$ spectra in a fashion opposite to neutrino mass. Estimates are obtained through a Fisher--matrix technique.

Gravitational Lensing Constraints on Dynamical and Coupled Dark Energy

Upcoming Weak Lensing (WL) surveys can be used to constrain Dark Energy (DE) properties, namely if tomographic techniques are used to improve their sensitivity. In this work, we use a Fisher matrix technique to compare the power of CMB anisotropy andpolarization data with tomographic WL data, in constraining DE parameters. Adding WL data to available CMB data improves the detection of all cosmological parameters, but the impact is really strong when DE--DM coupling is considered, as WL tomography can then succeed to reduce the errors on some parameters by factors >10.