Massive Neutrino Decay and Shape of the Galactic Dark Halo

In this Letter we investigate the basic assumptions of the decaying dark matter (DDM) theory in the light of recent advances in observational and theoretical cosmology and physics, i.e. detection of massive astrophysical compact halo objects (MACHOs) and Super-Kamiokande results. Specifically, the consequences pertaining to the shape of the Milky Way galaxy dark halo are discussed. We find that, by taking into account the values of the main constituent of the mass in DDM theory, massive neutrino, with the mass of 30 eV, and lifetime $\sim 10^{23}$ s, the initially proposed value of extreme halo flattening $q\sim 0.2$ is no longer necessary, and that one can easily accommodate a much larger value of $q\sim 0.6$, that is in accord with all available observational data.