The present status of the decaying neutrino theory

Abstract

Photons from decaying dark matter neutrinos in the Milky Way may be mainly responsible for the ionisation of the interstellar medium. This theory leads to a precise value for the mass of the decaying neutrinos (29.1 ± 0.1 ev) and a less precise value for the decay lifetime (2 ± 1 × 10 23 sec). Decay photons could also ionise the intergalactic medium and Lyman a clouds at large redshifts. This theory requires the universe to be close to critical (Ω ∼ 1) with a Hubble constant ∼ 56 ± 1 km sec −1 Mpc −1 . Recent observational evidence strongly supporting this theory has been obtained by Spitzer and Fitzpatrick who used the Hubble Space Telescope to observe a Galactic halo star. They found that the electron density is the same in four quiescent opaque clouds along the line of sight and that the ionised gas is probably completely mixed up with the opaque neutral gas in each cloud. Both these results are clear predictions of the neutrino decay theory, but would not be expected in conventional theories for the ionisation.