Search for Long Lived Particles that Stop in CMS

The CMS collaboration will search for long-lived particles that have become stopped by the CMS detector. The decay of such particles during time intervals where there are no $pp$ collisions would be a signal with low and easily measured backgrounds, coming from instrumental effects and cosmic rays. The search includes periods between gaps in the LHC bunch structure, and periods between dumping the beam and re-injection. Stopped particle decays will be collected using dedicated calorimeter triggers. For models such as split-supersymmetry gluinos, the relatively large cross-section combined with the relatively good stopping power of CMS, yields a significant number of triggerable decays. As the LHC instantaneous luminosity approaches $10^{32}$ cm$^{-2}$ s$^{-1}$, at $\sqrt s = 10$ TeV, a 5 sigma significance can be established in a matter of days.