Non-universal gaugino masses, the supersymmetric little hierarchy problem, and dark matter

TL;DR

This paper investigates supersymmetric models with non-universal gaugino masses, exploring their parameter space, dark matter implications, and how they address the little hierarchy problem, with implications for collider and dark matter detection experiments.

Contribution

It introduces a class of models with non-universal gaugino masses from SU(5) F-terms, analyzing their phenomenology and dark matter mechanisms, expanding beyond traditional mSUGRA scenarios.

Findings

Allowed parameter space divided into distinct regions.

Natural areas with lighter squarks and sleptons help address the little hierarchy problem.

Multiple dark matter annihilation mechanisms are viable, including co-annihilation and Higgs exchange.

Abstract

We study a class of supersymmetric models with non-universal gaugino masses that could arise from F-terms in a general combination of the singlet and adjoint representations of SU(5). We explore models that satisfy present Large Hadron Collider and other bounds, showing how the allowed parameter space is divided into distinct "continents". Regions of parameter space that ameliorate the supersymmetric little hierarchy problem with a small mu parameter include the usual focus point scenario, but also natural areas with much lighter squarks and sleptons. These models are continuously connected in parameter space to regions in which stau co-annihilation or Higgs exchange is mostly responsible for dark matter annihilation, and to models in which the thermal relic abundance is achieved by slepton-mediated annihilation, reviving the bulk region that is severely restricted in mSUGRA models. In hybrid or confluence regions, several mechanisms combine to give the requisite dark matter annihilation rate. In each case we study the prospects for direct detection of dark matter. We also comment briefly on the impact of recent hints for M_h near 125 GeV from the LHC.