Stable Massive States in 1+1 Dimensional NCOS

TL;DR

This paper investigates the stability and decoupling of massive open string states in 1+1 dimensional NCOS theory, providing amplitude examples and analyzing their decay into wound closed strings upon compactification.

Contribution

It offers new evidence for the decoupling of massive modes and identifies stable states in the gauge theory dual of 1+1 dimensional NCOS.

Findings

Massless open string modes decouple from massive modes.

Many massive open string states are stable in the decoupled regime.

Sufficiently massive states can decay into wound closed strings when compactified.

Abstract

We study the case of open string theory on a D1-brane in a critical electric field. It was argued in hep-th/0006085 that the massless open string modes of this theory decouple from the massive modes, corresponding to a decoupling of the U(1) degrees of freedom in the U(N) gauge theory dual. To provide further support for the decoupling, we present several examples of open string disk amplitudes. Because of the decoupling, many of the massive open string states are stable, indicating the presence of a number of correspondingly stable states in the gauge theory. We provide a lengthy list of these stable states. However, when the theory is compactified in the spatial direction of the electric field, we demonstrate that sufficiently massive such states may decay into wound closed strings.