Unification of fundamental interactions in supersymmetry

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.