Definitions

# Extended supersymmetry

In theoretical physics, extended supersymmetry is supersymmetry whose infinitesimal generators $Q_i^alpha$ carry not only a spinor index $alpha$, but also an additional index $i=1,2 dots mathcal\left\{N\right\}$ where $mathcal\left\{N\right\}$ is integer (such as 2 or 4).

Extended supersymmetry is also called $mathcal\left\{N\right\}=2$, $mathcal\left\{N\right\}=4$ supersymmetry, for example. The more extended supersymmetry is, the more it constrains physical observables and parameters. Only the minimal (un-extended) supersymmetry is a realistic conjecture for particle physics, but extended supersymmetry is very important for analysis of mathematical properties of quantum field theory and superstring theory.