String theory and the KLT-relations between gravity and gauge theory including external matter

@article{BjerrumBohr2004StringTA,
  title={String theory and the KLT-relations between gravity and gauge theory including external matter},
  author={N. Bjerrum-Bohr and Kasper Risager},
  journal={Physical Review D},
  year={2004},
  pages={086011}
}
We consider the Kawai-Lewellen-Tye (KLT) factorizations of gravity scalar-leg amplitudes into products of scalar-leg Yang-Mills amplitudes. We check and examine the factorizations at O(1) in $\alpha'$ and extend the analysis by considering KLT-mapping in the case of generic effective Lagrangians for Yang-Mills theory and gravity.