High energy γ-ray lines: a probe for a cold dark matter halo

We study the possibility of detecting halo cold dark matter through the annihilation process χχ-->γγ. This process produces monoenergetic γ-rays, and many be a clear signature of particle dark matter. If there is a closure density of photino -so far a favoured candidate -we show that it will be very difficult to observe this annihilation line from a satellite or space station borne experiment. On the contrary, triplet neutrinos which have recently been suggested as a plausible solution of the dark matter conundrum, whilst elusive at accelerators, should produce a clear γ-ray line signal, well above background.