The Light Gluino Mass Window Revisited

Abstract

The precise measurements of the ``electroweak observables'' performed at LEP and SLC are well consistent with the standard model predictions. Deviations from the standard model arising from vacuum polarization diagrams (also called ``weak loop corrections'') have been constrained in a model-independent manner with the epsilon formalism. Within the same formalism, additional deviations from new physics production processes can also be constrained, still in a model-independent way. For instance, a 95% C.L. limit of Delta Gamma_had} < 3.9 MeV is set on the partial width of any purely hadronic exotic contribution to Z decays. When applied to the e+e- -> q qbar gluino gluino process, it allows an absolute lower limit to be set on the gluino mass, m_gluino > 6.3 GeV/c2 at 95% C.L., which definitely closes the so-called light gluino mass window.