Cosmological implications of an anomalous U(1): Inflation, cosmic strings and constraints on superstring parameters

Abstract

A string-loop generated Fayet-Iliopoulos term can trigger, in four-dimensional superstring models with an anomalous U(1), the presence of global and local cosmic strings and, depending on the values of the string parameters M s (string scale) and M c (compactification scale), a period of inflationary expansion of the universe. The observational effects of inflation (density inhomogeneities) and cosmic strings (gravitational radiation, etc.) put severe bounds on the values of M s and M c.