Theory HEP Seminar

Cosmic strings from pseudo-anomalous Fayet-Iliopoulos U(1) in D3/D7 brane inflation

Rhiannon Gywn

King's College

D-term inflation is popular because it avoids the η problem prevalent in models of F-term inflation, and has a string embedding in D3/D7 brane inflation. In this model a flux on the D7 brane breaks SUSY and plays the role if a nonzero Fayet-Iliopoulos term, driving inflation. We revisit D3/D7 in the light of recent supergravity constraints on nonzero FI terms, and find that D3/D7 is in fact consistent with these constraints, since the FI term is necessarily field-dependent, corresponding to an anomalous U(1)_FI. This has implications for the cosmic strings produced at the end of D3/D7 inflation.