Probing supersymmetry beyond the reach of LEP2 at the Fermilab Tevatron: Low |M^3| dark matter models

In supersymmetric models where the magnitude of the GUT scale gaugino mass parameter M3 is suppressed relative to M1 and M2, the lightest neutralino can be a mixed higgsino-bino state with a thermal relic abundance in agreement with the WMAP central value for OmegaCDMh2 and consistent with all other phenomenological constraints. In these models, the gluino can be as light as 200 GeV without conflicting with the LEP2 bounds on the chargino mass. Thus, gluino pair production can be accessible at the Fermilab Tevatron at high rates. In this framework, gluinos decay radiatively with a large branching fraction to a gluon plus a neutralino. We find that experiments at the Fermilab Tevatron, with 5 fb-1 of integrated luminosity, will be sensitive to g-tilde g-tilde production in the mg-tilde~200–350 GeV range via the multi-jet+ETmiss and multi-jet+[script-l]+[script-l]-+ETmiss channels at the 5sigma level, while trilepton signatures are expected to be below this level of detectability. Dilepton mass edges from both Z-tilde2 and Z-tilde3 decays may be measurable in the dilepton+multi-jet+ETmiss channel.