Stable massive states in (1+1)-dimensional noncommutative open string theory - art. no. 046001

We study the case of open string theory on a D1-brane in a critical electri c field. It was argued by Klebanov and Maldacena that the massless open str ing 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 mass ive open string states are stable, indicating the presence of a number of c orrespondingly stable states in the gauge theory. We provide a lengthy list of these stable states. However, when the theory is compactified in the sp atial direction of the electric field, we demonstrate that such sufficientl y massive states may decay into wound-closed strings.