D-term inflation in non-minimal supergravity

TL;DR

This paper investigates the viability of D-term inflation within non-minimal supergravity frameworks, showing it can match observational data but cosmic strings remain a significant feature.

Contribution

It demonstrates that D-term inflation can be compatible with observations in non-minimal supergravity, highlighting persistent cosmic string effects regardless of Kähler potential choices.

Findings

D-term inflation predictions align with WMAP data in non-minimal supergravity.

Cosmic string contribution remains dominant unless superpotential coupling is finely tuned.

Non-flat Kähler geometry does not easily suppress cosmic string effects.

Abstract

D-term inflation is one of the most interesting and versatile models of inflation. It is possible to implement naturally D-term inflation within high energy physics, as for example SUSY GUTs, SUGRA, or string theories. D-term inflation avoids the $\eta$-problem, while in its standard form it always ends with the formation of cosmic strings. Given the recent three-year WMAP data on the cosmic microwave background temperature anisotropies, we examine whether D-term inflation can be successfully implemented in non-minimal supergravity theories. We show that for all our choices of K\"ahler potential, there exists a parameter space for which the predictions of D-term inflation are in agreement with the measurements. The cosmic string contribution on the measured temperature anisotropies is always dominant, unless the superpotential coupling constant is fine tuned; a result already obtained for D-term inflation within minimal supergravity. In conclusion, cosmic strings and their r\^ole in the angular power spectrum cannot be easily hidden by just considering a non-flat K\"ahler geometry.