  We analyze one loop scattering amplitudes of the massless states on a stack
of D3-branes. We use the vertex operators that have been obtained in the direct
open string analysis developed in arXiv:0708.3452. The method does not have the
obstacle of the D9 computation which is associated with the appearance of an
$\e$-tensor. The divergence structure is not the same as the D9 brane case.
What makes the analysis deviate from the D9 brane case is that the momenta of
the states have non-zero components only along the brane directions. We ponder
on the possibility that the one-loop divergence may be canceled by adding
additional vertex operators at the tree level. We anticipate that they will be
"exponentiated" to the free string action, with the resulting action to
constitute a non-linear sigma model of the D-brane/AdS geometry.

High Energy Physics - Theory