gluinos

Gluinos are the fermionic superpartners of gluons in supersymmetric theories such as the Minimal Supersymmetric Standard Model (MSSM). They are Majorana fermions and transform in the adjoint representation of the SU(3) color gauge group, giving them color charge and strong interactions. Their masses are model-dependent and can lie at the TeV scale in natural SUSY scenarios, but no experimental mass value has been observed.

Gluinos couple to quarks and squarks through supersymmetric QCD interactions and to gluons through the strong force. They are produced in pairs at hadron colliders by QCD processes, and their subsequent decays depend on the SUSY spectrum. In R-parity conserving models, gluinos typically decay to a pair of quarks plus a neutralino or chargino, via intermediate squarks or through off-shell squarks if squarks are heavy. This leads to events with multiple jets and missing transverse energy. In scenarios with long-lived gluinos, the particles can traverse the detector and form R-hadrons.

Experimental searches at the Large Hadron Collider have placed lower bounds on gluino masses that depend on the assumed decay pattern. In common simplified MSSM scenarios, gluino masses below roughly 2 TeV are excluded, with the exact limit shifting with the neutralino mass and decay chains.

The gluino is a key component of SUSY phenomenology, affecting gauge coupling unification, radiative corrections to masses, and the viability of SUSY dark matter scenarios. Its discovery would have profound implications for beyond-Standard-Model physics.