Search for stable hadronizing squarks and gluinos in e+e- collisions up to sqrt(s) = 209 GeV

TL;DR

This paper reports on searches for stable, hadronizing squarks and gluinos in electron-positron collisions up to 209 GeV, setting new mass limits and excluding certain supersymmetric particles at 95% confidence level.

Contribution

It provides the first comprehensive search for stable hadronizing squarks and gluinos at LEP energies, establishing new exclusion limits on their masses in supersymmetric models.

Findings

Stable stop quarks excluded up to 95 GeV/c2

Stable sbottom quarks excluded up to 92 GeV/c2

Stable gluinos excluded up to 26.9 GeV/c2

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- -> q qbar gluino gluino and q qbar squark antisquark processes. Stable squark pair production, and stop pair production with subsequent decays into a stable gluino, stop -> c gluino, 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) GeV/c2, and stable hadronizing gluinos are excluded up to 26.9 GeV/c2, 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 GeV/c2 is set on the stop quark mass.