A Natural 125 GeV Higgs Boson in the MSSM from Focus Point Supersymmetry with A-Terms

TL;DR

This paper demonstrates that the MSSM can naturally produce a 125 GeV Higgs with minimal fine-tuning by employing focus point supersymmetry with large A-terms, compatible with current experimental constraints.

Contribution

It introduces a focus point mechanism with specific GUT-scale relations that achieve a natural 125 GeV Higgs in the MSSM without additional fields.

Findings

Achieves a 125 GeV Higgs with minimal fine-tuning in the MSSM.

Predicts heavy superpartners but promising dark matter detection prospects.

Provides a framework compatible with LHC searches and current Higgs constraints.

Abstract

We show that a 125 GeV Higgs boson and percent-level fine-tuning are simultaneously attainable in the MSSM, with no additional fields and supersymmetry breaking generated at the GUT scale. The Higgs mass is raised by large radiative contributions from top squarks with significant left-right mixing, and naturalness is preserved by the focus point mechanism with large $A$-terms, which suppresses large log-enhanced sensitivities to variations in the fundamental parameters. The focus point mechanism is independent of almost all supersymmetry-breaking parameters, but is predictive in the top sector, requiring the GUT-scale relation $m_{H_u}^2 : m_{\bar{U}_3}^2 : m_{Q_3}^2 : A_t^2 = 1 : 1+x - 3y : 1-x : 9y$, where $x$ and $y$ are constants. We derive this condition analytically and then investigate three representative models through detailed numerical analysis. The models generically predict heavy superpartners, but dark matter searches in the case of non-unified gaugino masses are promising, as are searches for top squarks and gluinos with top and bottom-rich cascade decays at the LHC. This framework may be viewed as a simple update to mSUGRA/CMSSM to accommodate both naturalness and current Higgs boson constraints, and provides an ideal framework for presenting new results from LHC searches.