MSSM Higgs Physics at Higher Orders

TL;DR

This paper surveys the MSSM Higgs sector with a focus on higher-order corrections, detailing how radiative effects shift Higgs masses and couplings in both real-parameter (rMSSM) and complex-parameter (cMSSM) scenarios. It documents the Feynman-diagrammatic framework for calculating renormalized Higgs self-energies, including renormalization schemes, the α_eff approximation, and state-of-the-art two-loop contributions such as ${\cal O}(\alpha_t^2)$, ${\cal O}(\alpha_t\alpha_s)$, and ${\cal O}(\alpha_b\alpha_s)$, with sizable impact from sbottoms at large $\tan\beta$ via $\Delta m_b$. The work also compares FD results to RG approaches, clarifying how scheme choices affect leading logarithms and non-logarithmic terms, and demonstrates consistency after proper parameter translation. Finally, it discusses parametric and intrinsic theoretical uncertainties, quantifies current and future precision prospects (notably in $m_t$ and three-loop contributions), and outlines how improved predictions (as implemented in tools like FeynHiggs) will enable robust MSSM parameter constraints from LEP, LHC, and future $e^+e^-$ colliders.

Abstract

Various aspects of the Higgs boson phenomenology of the Minimal Supersymmetric Standard Model (MSSM) are reviewed. Emphasis is put on the effects of higher-order corrections. The masses and couplings are discussed in the MSSM with real and complex parameters. Higher-order corrections to Higgs boson production channels at a prospective e+ e- linear collider are investigated. Corrections to Higgs boson decays to SM fermions and their phenomenological implications for hadron and lepton colliders are explored.

Figures (11)

• Figure 1: The lightest Higgs boson mass is shown as a function of $M_A$ in the $m_h^{\rm max}$ and the no-mixing scenario benchmark, see the Appendix. $\tan \beta$ has been set to $\tan \beta = 3$ (lower curves) and $\tan \beta = 50$ (upper curves). The hybrid $\overline{\rm{DR}}$/on-shell scheme (solid lines) is compared with the original on-shell (type-1) renormalization (dashed). The dotted lines indicate the effect of the "subleading" ${\cal O}(\alpha_t^2)$ correction.
• Figure 2: Two-loop corrected $M_h$ as a function of $X_t$ in various steps of approximation. The relevant MSSM parameters are chosen as $\tan \beta=3\,,\, m_{t}^{\rm pole} = 174.3 \,\, \mathrm{GeV}$, $M_{\tilde{t}_L} = M_{\tilde{t}_R} = M_A = \mu = 1 \,\, \mathrm{TeV}$ and $m_{\tilde{g}} = 800 \,\, \mathrm{GeV}$. The meaning of the different curves is explained in the text.
• Figure 3: Generic Feynman diagrams for the $b/\tilde{b}$ contributions to Higgs boson self-energies (H = $h, H, A$).
• Figure 4: Generic Feynman diagrams for the $b/\tilde{b}$ contributions to Higgs tadpoles (H = $h, H$).
• Figure 5: The result for the lightest ${\cal CP}$-even Higgs-boson mass in the MSSM, $M_h$, as obtained with the program FeynHiggs is shown as a function of $\tan \beta$ for $M_A = 120$ GeV, $\mu = -1 \,\, \mathrm{TeV}$, $M_{\tilde{t}_L} = M_{\tilde{t}_R} = M_{\tilde{b}_R} = m_{\tilde{g}} = 1$ TeV, $A_t = A_b = 2 \,\, \mathrm{TeV}$. The meaning of the different curves is explained in the text.