dd637b1b_Particles_vs__strings__particles
[topic] graviton [strings] The existence of the graviton is required by known string theories, and thus predicted: This is true for the superstring, which has maximal supersymmetry (although it may be hidden in some formulations). It is also true for the bosonic string; however, that string has some consistency problems. Known string theories retain their predictive power in their critical dimension at all orders of perturbation; however, summation leads to the kind of effects (hidden dimensions) that are expected to destroy predictability. [particles] 
Maximal supersymmetry requires (super)gravity, so the existence of the graviton (particle of gravitational force) is predicted by that particle theory. However, treating the graviton as a fundamental particle leads to a loss of predictability, even at low orders of perturbation. A possible alternative is to treat the graviton as a composite state of other particles: Such theories have been constructed, but have not yet been shown to be predictive.
Particles vs. strings
particles