On the Scattering of Gravitons on Two Parallel D-Branes

I discuss the scattering of a graviton (or a dilaton, or an anti-symmetric tensor) on two parallel static Dp-branes. The graviton belongs to a type II string in 10D.Comment: 1+9 pages, TeX with macros include

A note on the Zakharov-Shabat topological model

In this note I discuss some features of the topological theory obtained from the Zakharov-Shabat (or general sl(2,C)) hierarchy, and comment on some possible physical and/or mathematical interpretations of it.Comment: 9 page

Scattering Amplitudes and the CPT theorem in String Theory

We discuss the role of the CPT transformation in first quantized string theories, both on the world-sheet and in the space-time. We explicitly show that the space-time CPT theorem holds for all first-quantized (perturbative) string theories in a Minkowski background of even dimension $D>2$.Comment: LaTeX2e, 8 pages, talk given at the Conference "Gauge Theories, Applied Supersymmetry and Quantum Gravity", London, July 199