MSSM Higgs Decays to Bottom Quark Pairs revisited

TL;DR

This work revisits neutral MSSM Higgs decays to bottom quark pairs with a focus on SUSY-QCD corrections enhanced by large tanβ and the μ parameter. It extends the resummation of leading non-decoupling effects by including possible Ab contributions through an effective low-energy Lagrangian, showing that Ab-induced NNLO terms are subdominant. The analysis demonstrates that the Δm_b resummation remains the dominant source of corrections and that residual scale uncertainties in decay widths are about 10%, with smaller but non-negligible uncertainties in nonleading branching ratios. Overall, the approach yields reliable predictions for the bb decay channel, while highlighting the need for NNLO SUSY-QCD and electroweak corrections for precision in subdominant modes.

Abstract

We present an update of neutral Higgs boson decays into bottom quark pairs in the minimal supersymmetric extension of the Standard Model. In particular the resummation of potentially large higher-order corrections due to the soft SUSY breaking parameters A_b and mu is extended. The remaining theoretical uncertainties due to unknown higher-order SUSY-QCD corrections are analyzed quantitatively.

Figures (6)

• Figure 1: One-loop contribution to the quantities (a)$\Delta_1$ and (b)$\Delta_2$.
• Figure 2: Non-decoupling two-loop contributions to $\Delta_1$ and $\Delta_2$
• Figure 3: Relative corrections due to (a) the SUSY--QCD corrections including the resummation of $\Delta m_b$ of Eq. (\ref{['eq:effpar']}) and (b) due to $\Delta_1$ of Eq. (\ref{['eq:d12']}) as a function of the pseudoscalar mass $M_A$ for all neutral Higgs bosons. The relative corrections are normalized to the QCD-corrected decay widths $\Gamma_{QCD}(\phi\to b\bar{b})$ of Eq. (\ref{['eq:gamqcd']}) in both cases.
• Figure 4: Relative deviations $\delta_\phi$ of the approximate low-energy one-loop result from the full NLO expression as a function of the pseudoscalar mass $M_A$ in the 'small $\alpha_{eff}$' scenario (a) for all neutral Higgs bosons. For the heavy scalar and pseudoscalar Higgs bosons the deviations are negative. The values shown have to be changed in sign.
• Figure 5: Partial decay widths $\Gamma(\phi\to b\bar{b})$ of (a) the light scalar, (b) the heavy scalar and (c) the pseudoscalar Higgs boson in the 'small $\alpha_{eff}$' scenario. The shaded bands reflect the uncertainties due to the scale choice of the strong coupling constant $\alpha_s$.