High Energy Scattering on Distant Branes

TL;DR

This paper analyzes high-energy elastic scattering of open strings on separated D-branes, revealing a phase transition at a critical separation and providing a quantum tunneling interpretation of the amplitude behavior.

Contribution

It introduces a detailed analysis of the high-energy scattering amplitude between open strings on D-branes, highlighting a phase transition and employing T-duality for interpretation.

Findings

Identification of a phase transition at v=1 in the scattering behavior.

Derivation of the amplitude's exponential suppression at high energy.

Use of T-duality to interpret quantum tunneling effects.

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 $\phi$ 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 $(v,\phi)$ 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.