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 Ms (string scale) and Mc (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 Ms and Mc.