SUSY QCD Corrections to Higgs-b Production : Is the \Delta_b   Approximation Accurate?
  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 \Delta_b approximation, is presented. The \Delta_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. 
S. Dawson, C. B. Jackson, P. Jaiswal
hep-ph