Giuseppe La Vacca, David F. Mota
We study and constraint Mass-Varying Neutrino models using present and future available data. In these models, dark energy is a self-interacting scalar field directly coupled to neutrinos. We investigate two different potentials and both positive and negative coupling parameter \beta. This corresponds to increasing or decreasing neutrino mass, respectively. We explore couplings up to |\beta|\lesssim 5. In the case of the exponential potential, we find upper limits on \omega_\nu<0.004 at 2-\sigma level. In the case of the inverse power law potential the null coupling can be excluded with more than 2-\sigma significance, the limits on the coupling being \beta>3 for the increasing neutrino mass and \beta<-1.5 for the decreasing mass case. This is a clear sign of a preference for higer couplings. When including a prior on the neutrino mass today the upper limits on the coupling become |\beta|<3 at 2-\sigma level for the exponential potential. Finally, we present Fisher forecast using the tomographic weak lensing from the Euclid-like experiment, also in combination with the CMB temperature and polarization spectra from the Planck-like mission. If considered alone, lensing data is very efficient in constraining \omega_\nu, giving a signal of a non-null neutrino mass with high significance. There is, however, a strong degeneracy in the \beta-\omega_\nu plane. When the two data sets are combined, the latter degeneracy remains, but the zero \beta value can be excluded at more than 2-\sigma.
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http://arxiv.org/abs/1205.6059
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