Mass Varying Neutrinos in Supernovae

We study the consequences on the neutrino oscillation parameter space, mixing angle ($\tan^2\theta$) and vacuum mass difference ($\Delta m^2_0$), when mass varying neutrino (MaVaN) models are assumed in a supernova environment. We consider electronic to sterile channels $\nu_e \rightarrow \nu_s$ and $\bar\nu_e \rightarrow \bar\nu_s$ in two-flavor scenario. In a given model of MaVaN mechanism, we induce a position-dependent effective mass difference, $\Delta \tilde m^2(r)$, where $r$ is the distance from the supernova core, that changes the neutrino and anti-neutrino flavour conversion probabilities. We study the constraints on the mixing angle and vacuum mass difference coming from r-process and the SN1987A data. Our result is the appearance of a new exclusion region for very small mixing angles, $\tan^2\theta=10^{-6}-10^{-2}$, and small vacuum mass difference, $\Delta m^2_0=~1-20$ eV$^2$, due the MaVaN mechanism.