Cosmological constant and kinetic supersymmetry breakdown on a moving brane

TL;DR

This paper explores how brane motion in five-dimensional supersymmetric theories leads to supersymmetry breaking and a positive cosmological constant on the brane, linking vacuum energy to supersymmetry breaking scale.

Contribution

It demonstrates that brane motion causes supersymmetry breakdown and relates the brane's vacuum energy to the supersymmetry breaking scale in 5d models.

Findings

Supersymmetry is broken by brane motion in the bulk.

The 4d vacuum energy is positive and inversely proportional to the square of brane local time.

Mass splitting in brane multiplets scales with the inverse of brane local time.

Abstract

We consider cosmological solutions in 5d locally supersymmetric theories including boundary actions, with either opposite tension branes for identical brane chiralities or equal tension branes for flipped brane chiralities. We analyse the occurrence of supersymmetry breakdown in both situations. We find that supersymmetry as seen by a brane observer is broken due to the motion of the brane in the bulk. When the brane energy-momentum tensor is dominated by the brane tension, the 4d vacuum energy cosmological constant on the observable brane is positive and proportional to the inverse square of the brane local time. We find that the mass splitting within supersymmetric multiplets living on the brane is of the order of the inverse of the brane local time, examplifying the tight relation between the vacuum energy scale and the supersymmetry breaking scale.