Implications of naturalness for the heavy Higgs bosons of supersymmetry

TL;DR

This paper explores how naturalness constraints in supersymmetry limit heavy Higgs boson masses and alter their decay patterns, impacting search strategies at colliders.

Contribution

It applies a unified naturalness measure to heavy Higgs bosons, deriving upper mass bounds and identifying new decay channels involving supersymmetric particles.

Findings

Heavy Higgs masses are bounded by naturalness, e.g., m_A<2.5 TeV for 10% fine-tuning at tan(beta)~10.

Light higgsinos significantly change heavy Higgs decay modes, reducing Standard Model final state signatures.

New decay signatures involve high p_T bosons plus missing energy, challenging current detection methods.

Abstract

Recently, it has been argued that various measures of SUSY naturalness-- electroweak, Higgs mass and EENZ/BG-- when applied consistently concur with one another and make very specific predictions for natural supersymmetric spectra. Highly natural spectra are characterized by light higgsinos with mass not too far from m_h and well-mixed but TeV-scale third generation squarks. We apply the unified naturalness measure to the case of heavy Higgs bosons A, H and H^\pm. We find that their masses are bounded from above by naturalness depending on tan(beta): e.g. for 10% fine-tuning and tan(beta)~ 10, we expect m_A< 2.5 TeV whilst for 3% fine-tuning and tan(beta) as high as 50, then m_A< 8 TeV. Furthermore, the presence of light higgsinos seriously alters the heavy Higgs boson branching ratios, thus diminishing prospects for usual searches into Standard Model (SM) final states, while new discovery possibilities arise due to the supersymmetric decay modes. The heavy SUSY decay modes tend to be H, A, H^\pm-> W, Z, or h+MET + soft tracks so that single heavy Higgs production is characterized by the presence of high p_T W, Z or h bosons plus missing E_T. These new heavy Higgs boson signatures seem to be challenging to extract from SM backgrounds.