Supergravity Inflation on the Brane

TL;DR

This paper explores supergravity inflation within braneworld models, demonstrating solutions to the eta-problem and establishing bounds on the fifth dimension scale based on inflationary potential forms and observational constraints.

Contribution

It shows how the eta-problem can be addressed in braneworld supergravity inflation and derives bounds on the fifth dimension scale from inflationary potential types.

Findings

Eta-problem can be solved in braneworld supergravity inflation.

Upper bound on fifth dimension scale for quadratic potential: M_5 q; 10^{-3} M_P.

For cubic potential, M_5 q; 9.2 imes 10^{-4} M_P.

Abstract

We study N=1 Supergravity inflation in the context of the braneworld scenario. Particular attention is paid to the problem of the onset of inflation at sub-Planckian field values and the ensued inflationary observables. We find that the so-called $\eta$-problem encountered in supergravity inspired inflationary models can be solved in the context of the braneworld scenario, for some range of the parameters involved. Furthermore, we obtain an upper bound on the scale of the fifth dimension, $M_5 \lsim 10^{-3} M_P$, in case the inflationary potential is quadratic in the inflaton field, $\phi$. If the inflationary potential is cubic in $\phi$, consistency with observational data requires that $M_5 \simeq 9.2 \times 10^{-4} M_P$.