Main Question or Discussion Point
is super symmetry real or has been predicted by string theory?
All true, but it is still worth saying that it is really only in string theory that supersymmetry arises naturally.- It's not a prediction by string theory but a necessary component of some string models. It's not something unique to string theory, though. You can apply supersymmetry more or less directly to the SM
Yes, I would be glad to know how does susy appear in string theory ? Is it a consequence of strings or extra-dimensions (which can be wo strings) or both or something else ?Taking the maximum extension of spacetime symmetries already appears relatively natural () to me. How does it "arise naturally" in string theory (also in the sense of "what does that mean?") and what does that mean about string models without susy? If susy automatically arises from a string approach, then it seems that non-susy string models shouldn't be possible.