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

Abstract

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 ${\alpha }^{\prime }$ and extend the analysis by considering KLT-mapping in the case of generic effective Lagrangians for Yang-Mills theory and gravity.

Comments: 7 pages, ReVTeX4, references updated, changes to text and typos corrected