Grand Unification in the Sky

The recent paper by Nardi, Sannino and Strumia arXiv:0811.4153v1 [hep-ph] introduces models of Decaying Dark Matter to explain the positron excess observed by the PAMELA and ATIC experiments. Decaying Dark Matter is natural in models of technicolor. It is less known, however, that it was the first paper suggesting to use astrophysical observations to investigate the idea of the “grand” unification of all the fundamental forces constituting the standard model of particle interactions. This work has already attracted much attention becoming a top 100 cited paper according to the SPIRES database.