γ rays from neutralino annihilation

We calculate the flux of cosmic {γ} rays expected from the annihilation of neutralinos in the galactic halo. Our calculation of the annihilation cross section to two photons improves the existing calculations by inclusion of exact one-loop diagrams for the amplitudes involving Higgs boson and chargino states as well as those involving fermion and sfermion states. A survey of supersymmetric parameter space shows that numerous models would be observable at the 3{σ} level with an air Cherenkov telescope with an exposure of 10⁴ m² yr.