Decaying neutrinos and the extragalactic background light

We present new calculations of the contributions to the intergalactic radiation field from light neutrinos of the type proposed by Sciama, with rest energies near 30 eV and radiative decay lifetimes of tau = (2 +/- 1) x 10(23) s. Experimental limits on the intensity of the diffuse ultraviolet background, while still controversial, can put useful lower bounds on the decay lifetime of these particles. These are centered around (2-3) x 10(23) s but range as high as (8 +/- 3) x 10(23) s. The model is thus in conflict with some observations but remains marginally compatible with most of them.