15 February 2015

Oh Really?

I saw a headline that the big particle accelerator at CERN, Switzerland, had been refitted to run higher energies than earlier tests, and might be ready to produce other never-before-seen particles. The accelerator, I'm sure you will recall, was first used to produce--and thereby confirm the existence of--the Higgs bosun.

The article mentioned that the new particle that might be produced is a "gluino." Not being familar with that term, I looked it up on Wikipedia.

And just loved the cogent description therein. Makes everything perfect clear.


A gluino is the hypothetical supersymmetric partner of a gluon. Should they exist, gluinos are expected by supersymmetry theorists to be pair produced in particle accelerators such as the Large Hadron Collider.

In supersymmetric theories, gluinos are Majorana fermions and interact via the strong force as a color octet. Gluinos have a lepton number 0, baryon number 0, and spin 1/2.

In models of supersymmetry that conserve R-parity, gluinos decay via the strong interaction to a squark and a quark, provided that an appropriate mass relation is satisfied. The squark subsequently decays to another quark and the lightest supersymmetric particle, LSP, which leaves the detector unseen. This means that a typical signal for a gluino at a hadron collider would be four jets plus missing energy.

However if gluinos are lighter than squarks, 3-body decay of a gluino to a neutralino and a quark antiquark pair is kinematically accessible through an off-shell squark.

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