UC Irvine

We consider a simple supersymmetric hidden sector: pure SU(N) gauge theory. Dark matter is made up of hidden glueballinos with mass mX and hidden glueballs with mass near the confinement scale Λ. For mX∼1TeV and Λ∼100MeV, the glueballinos freeze out with the correct relic density and self-interact through glueball exchange to resolve small-scale structure puzzles. An immediate consequence is that the glueballino spectrum has a hyperfine splitting of order Λ2/mX∼10keV. We show that the radiative decays of the excited state can explain the observed 3.5 keV x-ray line signal from clusters of galaxies, Andromeda, and the Milky Way.