Could intergalactic dust obscure a neutrino decay signature ?

Following recent results from the Super-Kamiokande experiment which indicate that neutrinos may have finite masses and provide at least part of the dark matter in the Universe, we reexamine the decaying neutrino hypothesis of Sciama, including for the first time the effects of absorption by intergalactic dust. We consider several dust models, including one designed to optimize ultraviolet extinction for a given dust-togas ratio. Dust absorption is insufficient to reconcile the theory with observational upper limits on the intensity of the diffuse ultraviolet background reported recently by Murthy et al. The theory remains marginally compatible with other diffuse background measurements.