It's not the graviton that's the scalar field--the massless scalar field is something string theory predicts which is not observed in nature--hence my scepticism that string field theory of any sort is actually the theory of nature. Well, that and 40 plus years without a testable prediction.
"Well, that and 40 plus years without a testable prediction."
Well, next year should be big when the LHC comes on line (though I would expect quite some time before "results" come out). However, I am skeptical as well, and I do not expect to hear about a new Higgs boson being found.
I don't understand this. What is the massless scalar field you're talking abut? Can you describe it?