Phenomenology of Light Gauginos

Abstract

I advocate the virtues of a very economical version of the minimal supersymmetric standard model which avoids cosmological problems often encountered in dynamical SUSY-breaking and solves the SUSY-CP problem. Imposing $m_Z=91$ GeV and $m_t \sim 175$ GeV implies that scalar masses are generally $100-200$ GeV. The gluino and photino are massless at tree level. At 1-loop, the gluino mass is predicted to be in the range $m_{\gluino}: 100 - 600$ MeV and the photino mass can be estimated to be $m_{\photino}: 100 - 1400$ MeV. New hadrons with mass $\sim 1 \frac{1}{2}$ GeV are predicted and described. The ``extra'' flavor singlet pseudoscalar observed in two experiments in the $ι(1440)$ region, if confirmed, is naturally interpreted as the state which gets its mass via the QCD anomaly. Its superpartner, a gluon-gluino bound state, generally has a lifetime longer than $5~10^{-11}$ sec and would not have shown up in existing searches. Search strategies and other consequences of the scenario are discussed.

21pp latex, including 3 figs