Stopping Gluinos

Long lived gluinos are the trademark of split supersymmetry. They form R-hadrons that, when charged, efficiently lose energy in matter via ionisation. Independent of R-spectroscopy and initial hadronization, a fraction of R-hadrons become charged while traversing a detector. This results in a large number of stopped gluinos at present and future detectors. For a 300 GeV gluino, $10^6$ will stop each year in LHC detectors, while several hundred stop in detectors during Run II at the Tevatron. The subsequent decays of stopped gluinos produce distinctive depositions of energy in calorimeters with no activity in either the tracker or the muon chamber. The gluino lifetime can be determined by looking for events where both gluinos stop and subsequently decay.