Supersymmetry (SUSY) is a particular type of extension to the standard model of particle physics that theorizes an additional set of leptons and bosons with an additional lepton corresponding to each known boson and vice versa. The additional particles (superparticles) would have a spin quantum number which is 1/2 different from the corresponding known particle. Some superparticle terms:
|known lepton||supersymmetric boson|
|known boson||supersymmetric lepton|
Neutralinos would be a result of quantum mixing of some of the superparticles.
Supergravity (SUGRA) is a supersymmetry theory variant that also incorporates general relativity.