Microscopic unitary description of tidal excitations in high-energy string-brane collisions

D'APPOLLONIO, GIUSEPPE;Di Vecchia P;Russo R;Veneziano G.

2013-01-01

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Abstract

The eikonal operator was originally introduced to describe the effect A tidal excitations on higher-genus elastic string amplitudes at high energy. In this paper we provide a precise interpretation for this operator through the explicit tree-level calculation of generic inelastic transitions between closed strings as they scatter off a stack of parallel Dp-branes. We perform this analysis both in the light-cone gauge, using the Green-Schwarz vertex, and in the covariant formalism, using the Reggeon vertex operator. We also present a detailed discussion of the high-energy behaviour of the covariant string amplitudes, showing how to take into account the energy factors that enhance the contribution of the longitudinally polarized massive states in a simple way.