A lower limit to the mass of neutral leptons as constituents of the dark halo around galaxies

We have found that the structural equations governing the hydrostatic equilibrium of a thermally relaxed, spherically-symmetric neutral lepton system with a density profile that can account for the dark matter distribution around spiral galaxies donot admit any physically reasonable solutions (namely the temperature should be positive definite and monotonically decreasing with distance) if the lepton mass is 17 eV.