Experimental and Cosmological Implications of Light Gauginos

Abstract

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.

Based on talks presented at the 9th Intl. Baksan School "Particles and Cosmology", INR Baksan, Russia, March 1997 and at the Intl. Workshop on Physics Beyond the Desert, Tegernsee, Germany, June 1997. 14 pages including 4 figures