High Energy Scattering on Distant Branes

Abstract

We consider the elastic scattering of two open strings living on two D-branes separated by a distance $r$. We compute the high-energy behavior of the amplitude, to leading order in string coupling, as a function of the scattering angle $\varphi$ and of the dimensionless parameter $v=r/(\pi {\alpha }^{\prime }\sqrt{s})$ with $\sqrt{s}$ the center-of-mass energy. The result exhibits an interesting phase diagram in the $(v,\varphi )$ plane, with a transition at the production threshold for stretched strings at $v=1$. We also discuss some more general features of the open-string semiclassical world-sheets, and use T-duality to give a quantum tunneling interpretation of the exponential suppression at high-energy.

Comments: JHEP class, 18 pages, 8 figures