Supersymmetric interpretation of the Egret GeV anomaly, Xenon-10 dark matter search limits, and the CERN LHC

The observation of the Egret experiment of an excess of diffuse gamma rays with energies above Eγ=1 GeV has previously been interpreted in the context of the minimal supergravity model (mSUGRA) as coming from neutralino annihilation into mainly b-quarks in the galactic halo, with neutralino mass in the vicinity of 50-70 GeV. We observe that, in order to obtain the correct relic abundance of neutralinos in accord with WMAP measurements, the corresponding neutralino-proton direct detection (DD) rates should be in excess of recent limits from the Xenon-10 collaboration. While it does not appear possible to satisfy the Egret, WMAP, and Xenon-10 constraints simultaneously within the mSUGRA model, we find that it is easily possible in models with nonuniversal Higgs soft masses (NUHM). In either case, gluino pair production from mg-tilde∼400-500 GeV should occur at large rates at the CERN LHC, and a gluino pair production signal should be visible with just 0.1 fb-1 of integrated luminosity. The NUHM interpretation predicts a rather light spectrum of heavy Higgs bosons with mA∼140-200 GeV over the whole parameter space which would interpret Egret data. Spin-independent DD rates are predicted to be just above 10-8 pb, within range of the next round of direct dark matter detection experiments.