Radiative Scherk-Schwarz supersymmetry breaking

TL;DR

This paper investigates how Scherk-Schwarz supersymmetry breaking in five-dimensional orbifold models is determined at the loop level, showing it is fixed to specific values and affected by brane-localized breaking effects.

Contribution

It demonstrates that the Scherk-Schwarz breaking parameter is radiatively fixed to discrete values and explores the interaction with brane-localized supersymmetry breaking.

Findings

SS parameter fixed at 0 or 1/2 depending on bulk matter content

Loop corrections determine the SS breaking parameter

Brane-localized breaking modifies the SS spectrum shifts

Abstract

We analyze the Scherk-Schwarz (SS) supersymmetry breaking in brane-world five dimensional theories compactified on the orbifold $S^1/\mathbb{Z}_2$. The SS breaking parameter is undetermined at the tree-level (no-scale supergravity) and can be interpreted as the Hosotani vacuum expectation value corresponding to the $U(1)_R$ group in five dimensional N=2 (ungauged) supergravity. We show that the SS breaking parameter is fixed at the loop level to either 0 or 1/2 depending on the matter content propagating in the bulk but in a rather model-independent way. Supersymmetry breaking is therefore fixed through a radiative Scherk-Schwarz mechanism. We also show that the two discrete values of the SS parameter, as well as the supersymmetry breaking shift in the spectrum of the bulk fields, are altered in the presence of a brane-localized supersymmetry breaking arising from some hidden sector dynamics. The interplay between the SS and the brane localized breaking is studied in detail.