Three-Point Disc Amplitudes and Higher Derivative Couplings

Abstract

This dissertation discusses the string disc amplitudes and D-brane higher derivative couplings. In the first part, we investigate all tree-level string theory vacuum to D-brane disc amplitudes involving an arbitrary RR-state and two NS-NS vertex operators. Our method is that, we develop an algorithm to derive the amplitudes in a manifestly gauge invariant and exchange invariant form, then we implement the algorithm on computer to systematically solve the amplitudes. In the second part, we derive the four-derivative brane interactions for one R-R field C^(p+5) and two NS-NS B-fields based on the amplitude from the first part. We find the effective coupling actually vanishes, which implies the interaction obeys a non-renormalization theorem.