If you spend some time looking in detail at the arguments that string theory requires supersymmetry, you'll find that they are not watertight. (how could they be, since we still can't say/don't know … I have been thinking about the definition of the notation $\\cal n$ and its relation to the number of supercharges in susy, but still feel a little confused.

In particle physics, supersymmetry (often abbreviated susy) is a symmetry that relates elementary particles of one spin to other particles that differ by half a unit of spin and are