Experimental and Cosmological Implications of Light Gauginos

Gauginos may be nearly massless at tree level, with loop corrections giving a gluino mass of order 100 MeV and a photino mass of order 1 GeV. Relic photinos can naturally account for the observed dark matter, but their detection is more difficult than for conventional WIMPs. The lightest gluino-containing baryon could account for the recently observed ultra-high energy cosmic rays, which violate the GZK bound. The predicted mass and properties of the gluino-gluino boundstate agree with those of the eta(1410), a flavor singlet pseudoscalar meson which has proved difficult to reconcile with QCD predictions. Laboratory experiments presently exclude only a small portion of the interesting parameter space, although improvements expected in the next year may lead to complete exclusion or discovery.