Search for stopped gluinos from $parp$ collisions at $sqrts$ = 1.96-TeV

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_s14 decays, occurring up to 100 hours after their production and not synchronized with an accelerator bunch crossing. We apply the analysis to the gluino (~g), 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 p-pbar collisions at 1.96 TeV collected with the D0 detector during Run II of the Fermilab Tevatron collider are analyzed in search of such ``stopped gluinos_s14_s14 decaying into a gluon and a neutralino (~X_0), reconstructed as a jet and missing energy. No excess is observed above background, and limits are placed on the (gluino cross section) x (probability to stop) x BR(~g -> g ~X_0) as a function of the gluino and ~X_0 masses, for gluino lifetimes from 30 $mu$s -- 100 hours.