Neutrino physics from future weak lensing surveys

Given recent indications of additional neutrino species and cosmologically significant neutrino masses, we analyze their signatures in the weak lensing shear power spectrum. We find that a shear deficit in the 20-40% range or excess in the 20-80% range cannot be explained by variations in parameters of the flat ΛCDM model that are allowed by current observations of the expansion history from Type Ia supernovae, baryon acoustic oscillations, and local measures of the Hubble constant H0, coupled with observations of the cosmic microwave background from WMAP and SPT. Hence such a shear deficit or excess would indicate large masses or extra species, respectively, and we find this to be independent of the flatness assumption. We also discuss the robustness of these predictions to cosmic acceleration physics and the means by which shear degeneracies in joint variation of mass and species can be broken.