Axion Mediation

TL;DR

This paper investigates axion-mediated supersymmetry breaking, proposing a general effective field theory framework that encompasses various models, and discusses its implications for particle spectra, cosmology, and string theory.

Contribution

It introduces a comprehensive effective field theory approach to axion mediation of supersymmetry breaking, covering minimal and non-minimal models, and explores its theoretical and phenomenological implications.

Findings

Axion mediation can dominate gravity mediation in supersymmetry breaking.

It reduces cosmological constraints from axino and gravitino overproduction.

Provides a natural mechanism for flavor problem mitigation in string theory contexts.

Abstract

We explore the possibility that supersymmetry breaking is mediated to the Standard Model sector through the interactions of a generalized axion multiplet that gains a F-term expectation value. Using an effective field theory framework we enumerate the most general possible set of axion couplings and compute the Standard Model sector soft-supersymmetry-breaking terms. Unusual, non-minimal spectra, such as those of both natural and split supersymmetry are easily implemented. We discuss example models and low-energy spectra, as well as implications of the particularly minimal case of mediation via the QCD axion multiplet. We argue that if the Peccei-Quinn solution to the strong-CP problem is realized in string theory then such axion-mediation is generic, while in a field theory model it is a natural possibility in both DFSZ- and KSVZ-like regimes. Axion mediation can parametrically dominate gravity-mediation and is also cosmologically beneficial as the constraints arising from axino and gravitino overproduction are reduced. Finally, in the string context, axion mediation provides a motivated mechanism where the UV completion naturally ameliorates the supersymmetric flavor problem.