Observable monochromatic photons from cosmic photino annihilation

A recent suggestion that the observations of monochromatic photons from annihilation of photinos into quarkonium plus a photon could be a signature of dark-matter photinos is extended to include all S- and P-wave bound quarkonium states for a general interaction Lagrangian and an estimate of the cross sections is given. We also propose the process λlambda-bar→γγ as a potentially rich source of monochromatic photons and estimate its strength