A microscopic description of absorption in high-energy string-brane collisions

We study the collision of a highly energetic light closed string off a stack of dp-branes at (sub)string-scale impact parameters and in a regime justifying a perturbative treatment. unlike at larger impact parameters — where elastic scattering and/or tidal excitations dominate — here absorption of the closed string by the brane system, with the associated excitation of open strings living on it, becomes important. as a first step, we study this phenomenon at the disk level, in which the energetic closed string turns into a single heavy open string at rest whose particularly simple properties are described.