Unification of Fundamental Interactions in Supersymmetry

Abstract

A review is given of recent developments on the implications of supergravity grand unification with SU(5)-type proton decay under the condition $M_{H_3} /m_G < 10$ (where $M_{H_3}$ is the Higgs triplet mass) and the naturalness condition that the universal scalar mass $m_0$ and the gluino mass are $<$ 1~TeV. It is shown that the maximum achievable lifetime limits on proton lifetime at Super Kamiokande and ICARUS will exhaust the full parameter space of the model under the constraint $m_{\tilde W_1} >$~100~GeV. Thus the model predicts the observation of either a light chargino with mass $\lappeq$~100~GeV , or the observation of a $\bar \nu K^+$ mode at Super Kamiokande and ICARUS within the above naturalness constraints.Analysis of the $b \rightarrow s\gamma $ branching ratio within this model is also discussed. It is shown that there is a significant region of the parameter space where the branching ratio predicted by the model lies within the current experimental bounds. It is pointed out that improved measurements of $B(b\rightarrow s\gamma)$ will significantly delineate the parameter space of the model and allow for a more stringent determination of their allowed ranges.