Weakly-Coupled Higgs Bosons

TL;DR

This paper surveys weakly-coupled Higgs bosons across the Standard Model and minimal supersymmetric extensions, analyzing theoretical bounds, decay patterns, and collider discovery prospects. It emphasizes the complementary roles of hadron colliders (LHC/Tevatron/DiTevatron) and lepton facilities (NLC, muon colliders, gamma-gamma modes) in discovering and characterizing Higgs states, including the MSSM's h^0,H^0,A^0,H^± spectrum and possible extensions with singlets. A central theme is the precision measurement of Higgs properties (masses, widths, couplings, CP quantum numbers) and how joint analyses across collider types can disentangle SM-like Higgs behavior from MSSM (or MNMSSM) deviations, particularly via channels such as $\gamma\gamma$, $ZZ^{(*)}$, $WW^{(*)}$, and fermionic modes. The work highlights two-loop/RGE improvements for MSSM Higgs masses, the impact of stop mixing, and the pivotal role of $b$-tagging and flavor tagging in MSSM Higgs discovery, especially in the challenging region of moderate $m_{A^0}$ and large $\tan\beta$. Overall, the paper argues that a coordinated, multi-modal collider program can comprehensively probe the Higgs sector, testing custodial relations, loop-induced couplings, and potential new physics in the Higgs sector with high precision and broad mass reach.

Abstract

We review the search for the standard Higgs boson, the Higgs bosons of the supersymmetric standard model, and Higgs bosons from a variety of other models at present and future colliders.

Figures (33)

• Figure 1: Couplings of the standard Higgs boson to weak vector bosons and fermions. The coupling to weak vector bosons is multiplied by the metric tensor $g^{\mu\nu}$.
• Figure 2: Contours for the $h^0$ and $H^0$ masses in $(m_{A^0},\tan\beta)$ parameter space. Results are given for $m_t=175\,{\rm GeV}$, with $m_{\widetilde{t}}=1\,{\rm TeV}$ (upper plots) and $m_{\widetilde{t}}=500\,{\rm GeV}$ (lower plots). The masses are computed including two-loop/RGE-improved radiative corrections, neglecting squark mixing.
• Figure 3: Ratios of SUSY Higgs squared couplings to the corresponding SM values as a function of $m_{A^0}$ for the case of $\tan\beta=5$, taking $m_t=175\,{\rm GeV}$ and $m_{\widetilde{t}}=1\,{\rm TeV}$. Two-loop/RGE-improved radiative corrections to the CP-even Higgs sector mass matrix are included and squark mixing is neglected.
• Figure 4: Branching ratios for the Standard Model Higgs boson. We have taken $m_t=175\,{\rm GeV}$.
• Figure 5: Selected branching ratios for the MSSM $H^0$ for $\tan\beta=2$ and $m_t=175\,{\rm GeV}$. Two-loop/RGE-improved radiative corrections to the CP-even Higgs sector mass matrix and Higgs self-couplings are included for $m_{\widetilde{t}}=1\,{\rm TeV}$ and neglecting squark mixing. SUSY decays are assumed to be absent.