Cosmic strings from pseudo-anomalous U(1)'s

Abstract

We discuss the properties of cosmic strings based on a spontaneously broken anomalous U(1) when the anomalies are cancelled via the Green-Schwarz mechanism. Such strings arise in a large class of cuperstrings compactification act as a source for an axion-like field which has model dependent couplings to QCD and QED. If this field couples to QED, but not to QCD, these strings could exist today and would exhibit novel optical properties. Such strings could be distinguished from other types of cosmic strings by studying the relative polarization of the images they produce when acting as gravitational lenses. If the axion-like field produced by these strings does couple to QCD, these strings as well as macroscopic heterotic superstrings would become the boundaries of domain walls and would rapidly disappear. There would be, however, bound configurations of the two types of string which do not couple to QCD and which could exist in the present universe.