Abstract: | Long-lived, heavy particles are predicted in a number of models beyond the standard model of particle physics. We present the first direct search for such particles’ decays, occurring up to 100 h after their production and not synchronized with an accelerator bunch crossing. We apply the analysis to the gluino (g[over ]), predicted in split supersymmetry, which after hadronization can become charged and lose enough momentum through ionization to come to rest in dense particle detectors. Approximately 410 pb;{-1} of pp[over ] collisions at sqrt[s]=1.96 TeV collected with the D0 detector during Run II of the Fermilab Tevatron collider are analyzed in search of such "stopped gluinos" decaying into a gluon and a neutralino (chi[over ]_{1};{0}). Limits are placed on the (gluino cross section)x(probability to stop)x[BR(g[over ]-->gchi[over ]_{1};{0})] as a function of the gluino and chi[over ]_{1};{0} masses, for gluino lifetimes from 30 mus-100 h. |