Brane-Worlds Pseudo-Goldstinos

TL;DR

This paper explores how pseudo-Goldstinos arise in a five-dimensional brane-world model with supersymmetry breaking, detailing the super Higgs mechanism and providing explicit formulas for the spectrum of pseudo-Goldstinos.

Contribution

It introduces a new auxiliary field extension of 5D supergravity and analyzes the super Higgs mechanism with combined bulk and brane supersymmetry breaking.

Findings

Explicit formulas for pseudo-Goldstino spectrum.

Analysis of super Higgs mechanism with Scherk-Schwarz and brane F-terms.

Extension of supergravity with auxiliary fields.

Abstract

We consider a space-time with extra dimensions containing sectors, branes and bulk, that communicate only through gravitational interactions. In each sector, if considered separately, supersymmetry could be spontaneously broken, leading to the appearance of Goldstinos. However, when taken all together, only certain combinations of the latter states turn out to be true ``would be Goldstinos'', eaten by the gravitinos. The other (orthogonal) combinations, we call pseudo-Goldstinos, remain in the low energy spectrum. We discuss explicitly how this happen in the simplest set-up of five-dimensional space compactified on S^1/Z_2 . Our results divide into two parts that can be considered separately. First, we build an extension of the bulk five-dimensional supergravity, by a set of new auxiliary fields, that allows coupling it to branes where supersymmetry is spontaneously broken. Second, we discuss in details the super Higgs mechanism in the R_\xi and unitary gauges, in the presence of both of a bulk Scherk-Schwarz mechanism and brane localized F-terms. This leads us to compute the gravitino mass and provide explicit formulae for the pseudo-Goldstinos spectrum.