Search for stable hadronizing squarks and gluinosin e + e- collisions up to $\sqrt{s} = 209$ GeV

Abstract.Searches for stable, hadronizing scalar quarks and gluinos are performed using the data collected with the ALEPH detector at LEP. Gluon splitting into a gluino or a squark pair is searched for at centre-of-mass energies around the Z resonance, in the e + e-$\to \ensuremath{{\rm q\bar{q}}}\ensuremath{{\tilde{\rm g}}}\ensuremath{{\tilde{\rm g}}}$ and $\ensuremath{{\rm q\bar{\rm q}}}\ensuremath{\tilde{\rm q}\bar{\tilde{\rm q}}}$ processes. Stable squark pair production, and stop pair production with subsequent decays into a stable gluino, $\ensuremath{{\tilde{\rm t}}} \to {\rm c} \ensuremath{{\tilde{\rm g}}}$, are also directly searched for at centre-of-mass energies from 183 to 209 GeV. Altogether, stable hadronizing stop (sbottom) quarks are excluded up to masses of 95 (92) $\ensuremath{{\rm GeV}\!/c^2}$, and stable hadronizing gluinos are excluded up to 26.9 $\ensuremath{{\rm GeV}\!/c^2}$, at 95% confidence level. In the framework of R-parity-conserving supersymmetric models in which the gluino and the stop quark are the two lightest supersymmetric particles, a 95% C.L. lower limit of 80 $\ensuremath{{\rm GeV}\!/c^2}$ is set on the stop quark mass.