摘要
<p>We consider the possibility that the lightest supersymmetric particle is a heavy gluino. After discussing models in which this is the case, we demonstrate that the g˜ -LSP could evade cosmological and other constraints by virtue of having a very small relic density. We then consider how neutral and charged hadrons containing a gluino will behave in a detector, demonstrating that there is generally substantial apparent missing momentum associated with a produced g˜ -LSP. We next investigate limits on the g˜ -LSP deriving from CERN, LEP, LEP2 and run I Fermilab Tevatron experimental searches for excess events in the jets plus missing momentum channel and for stable heavily ionizing charged particles. The range of m<sub>g˜</sub> that can be excluded depends upon the path length of the g˜ in the detector, the amount of energy it deposits in each hadronic collision, and the probability for the g˜ to fragment to a pseudo-stable charged hadron after a given hadronic collision. We explore how the range of excluded m<sub>g˜</sub> depends upon these ingredients, concluding that for non-extreme case the range <span lang="EN-US" style="font-size:10.0pt"><span style="font-family:"Times New Roman","serif"">3 GeV</span></span><span style="font-size:10.0pt"><span style="font-family:"新細明體","serif"">≦</span></span><span lang="EN-US" style="font-size:10.0pt"><span style="font-family:"Times New Roman","serif"">m<sub>g~</sub></span></span><span style="font-size:10.0pt"><span style="font-family:"新細明體","serif"">≦130-150 GeV</span></span> can be excluded at 95% C.L. based on currently available OPAL and CDF analyses. We find that run II at the Tevatron can extend the excluded region (or discover the g˜) up to m<sub>g˜ </sub>~ 160– 180 GeV. For completeness, we also analyze the case where the g˜ is the NLSP (as possible in gauge-mediated supersysmmetry breaking) decaying via g˜ -> g+gravitino. We find that the Tevatron run I data exclude m<sub>g˜</sub><span style="font-size:10.0pt"><span style="font-family:"新細明體","serif"">≦</span></span>240 GeV. Finally, we discuss application of the procedures developed for the heavy g˜ -LSP to searches for other stable strongly interacting particles, such as a stable heavy quark.</p>