String Mediated Supersymmetry Breaking

Abstract

We consider the 3+1 visible sector to live on a Hanany-Witten D-brane construction in type IIA string theory. The messenger sector consists of stretched strings from the visible brane to a hidden D6-brane in the extra spatial dimensions. In the open string channel supersymmetry is broken by gauge mediation while in the closed string channel supersymmetry is broken by gravity mediation. Hence, we call this kind of mediation "string mediation". We propose an extension of the Dimopoulos-Georgi theorem to brane models: only detached probe branes can break supersymmetry without generating a tachyon. Fermion masses are generated at one loop if the branes break a sufficient amount of the ten dimensional Lorentz group while scalar potentials are generated if there is a force between the visible brane and the hidden brane. Scalars can be lifted at two loops through a combination of brane bending and brane forces. We find a large class of stable nonsupersymmetric brane configurations of ten dimensinoal string theory.

Brane inflation and reheating

“…Our concrete starting point involves the branes of ten-dimensional type IIA string theory. In [11], a similar configuration was considered within the context of 'string mediated' supersymmetry breaking in a Hanany-Witten model with rotated D6-branes. This model allows us to break supersymmetry at the string scale in some very heavy non-MSSM messenger fields (the 4-6 strings) and then communicate the SUSY breaking to the inflaton field living on the D4-brane world at a lower scale.…”

“…During the reheat process the inflaton will decay into these chiral fields. Since, in this picture, the inflaton is a brane mode the reheating process should be quite efficient 11 . Consider the inflaton scalar φ interacting with a scalar field χ and a spinor field ψ that live on the brane by the interaction…”

“…See the models[4,20] for two exceptions 11. For detailed discussions of the reheating process, see, e.g.,[22]-[25].Journal ofCosmology and Astroparticle Physics 12 (2003) 004 (stacks.iop.org/JCAP/2003/i=12/a=004)…”