Perturbative and non-perturbative partial supersymmetry breaking: N = 4 → N = 2 → N = 1 Original Research Article

We show the existence of a supersymmetry breaking mechanism in string theory, where N = 4 supersymmetry is broken spontaneously to N = 2 and N = 1 with moduli-dependent gravitino masses. The spectrum of the spontaneously broken theory with lower supersymmetry is in one-to-one correspondence with the spectrum of the heterotic N = 4 string. The mass splitting of the N = 4 spectrum depends on the compactification moduli as well as the three R-symmetry charges. We also show that, in string theory, chiral theories can be obtained after spontaneous breaking of extended supersymmetry. This was impossible at the level of field theory.