SUSY QCD Corrections to Higgs-b Production : Is the Δ_b Approximation Accurate?

TL;DR

The paper addresses the accuracy of the Δ_b effective-Lagrangian approach for SUSY QCD corrections to Higgs production in association with a bottom quark in the 5 flavor scheme. It develops exact one-loop SQCD calculations including mb tanβ enhanced terms and compares them to the Improved Born Approximation, providing analytic results in the maximal and minimal b-squark mixing limits and exploring large M_S decoupling. The numerical study at √s = 7 TeV demonstrates that Δ_b reproduces the full one-loop results to within a few percent across a wide MSSM parameter range, with residual non-Δ_b terms suppressed by M_EW^2/M_S^2 and decoupling tied to M_A. The work validates the use of the Δ_b approach for phenomenology and refines 7 TeV predictions for bh production in the MSSM, informing Higgs searches at the LHC.

Abstract

The associated production of a Higgs boson with a b quark is a discovery channel for the lightest MSSM neutral Higgs boson. We consider the SUSY QCD contributions from squarks and gluinos and discuss the decoupling properties of these effects. A detailed comparison of our exact order(alpha_s) results with those of a widely used effective Lagrangian approach, the Δ_b approximation, is presented. The Δ_b approximation is shown to accurately reproduce the exact one-loop SQCD result to within a few percent over a wide range of parameter space.

Figures (17)

• Figure 1: Feynman diagrams for $g(q_1)+b (q_2)\rightarrow b(p_b)+ h(p_h)$.
• Figure 2: Contribution of $\delta \kappa_{max}$ defined in Eq. \ref{['dkapmax']} as a function of $R=M_{\tilde{g}}/M_S$.
• Figure 3: Contribution of $\delta \kappa_{min}$ defined in Eq. \ref{['minkapdef']} as a function of $R_i=M_{\tilde{g}}/M_{{\tilde{b}}_i}$ .
• Figure 4: Percentage difference between the Improved Born Approximation and the exact one-loop SQCD calculation of $pp\rightarrow bh$ for maximal mixing in the $b$-squark sector at $\sqrt{s}=7~TeV$, $\tan\beta=40$, and $M_A=1~TeV$.
• Figure 5: Percentage difference between the Improved Born Approximation and the exact one-loop SQCD calculation of $pp\rightarrow bh$ for maximal mixing in the $b$-squark sector at $\sqrt{s}=7~TeV$, $\tan\beta=20$, and $M_A=250~GeV$.