Selection Rules and RR Couplings on Non-BPS Branes

TL;DR

This paper analyzes non-BPS brane scattering amplitudes in type II superstring theories, deriving selection rules that restrict possible interactions and revealing a unique tachyon amplitude expansion.

Contribution

It introduces a novel expansion for tachyon amplitudes and proposes comprehensive selection rules for non-BPS scattering processes in type II superstring theories.

Findings

Derived three and four point non-BPS scattering amplitudes.

Discovered a unique tachyon amplitude expansion.

Proposed selection rules that eliminate certain higher point functions.

Abstract

We compute three and four point functions of the non-BPS scattering amplitudes, including a closed string Ramond-Ramond, gauge/scalar and tachyon in type IIA (IIB) superstring theories. We then discover a unique expansion for tachyon amplitudes in both non-BPS and D-brane anti D-brane formalisms. Based on remarks on Chan-Paton factors and arXiv:1304.3711, we propose selection rules for all non-BPS scattering amplitudes of type II superstring theory. These selection rules, rule out various non-BPS higher point correlation functions of the string theory.