Relativistic D-brane Scattering is Extremely Inelastic

We study the effects of quantum production of open strings on therelativistic scattering of D-branes. We find strong corrections to the branetrajectory from copious production of highly-excited open strings, whosetypical oscillator level is proportional to the square of the rapidity. In thecorrected trajectory, the branes rapidly coincide and remain trapped in aconfiguration with enhanced symmetry. This is a purely stringy effect whichmakes relativistic brane collisions exceptionally inelastic. We trace thiseffect to velocity-dependent corrections to the open-string mass, which renderopen strings between relativistic D-branes surprisingly light. We observe thatpair-creation of open strings could play an important role in cosmologicalscenarios in which branes approach each other at very high speeds.Comment: 30 pages; added references and a comment about velocity-dependent masse