Model independent constraints on mass-varying neutrino scenarios

Understand

Models of dark energy in which neutrinos interact with the scalar field supposed to be responsible for the acceleration of the universe usually imply a variation of the neutrino masses on cosmological time scales.

• In this work we propose a parameterization for the neutrino mass variation that captures the essentials of those scenarios and allows to constrain them in a model independent way, that is, without resorting to any particular scalar field model.
• Using WMAP 5yr data combined with the matter power spectrum of SDSS and 2dFGRS, the limit on the present value of the neutrino mass is $m_0 \equiv m_{\nu}(z=0) < 0.43 (0.28)$ eV at 95% C.L.
• for the case in which the neutrino mass was lighter (heavier) in the past, a result competitive with the ones imposed for standard (i.e., constant mass) neutrinos.