Neutralino decay of MSSM neutral Higgs bosons

We compute the one-loop corrected effective Lagrangian for the neutralino-neutralino-neutral Higgs interactions χ_ℓ⁰χ_k⁰H_m⁰. The analysis completes the previous analyses where similar corrections were computed for the fmacr fH_m⁰ couplings, where f stands for standard model quarks and leptons and for the chargino-chargino-neutral Higgs couplings χ_l⁺χ_k^-H_m⁰ within the minimal supersymmetric standard model. The effective one-loop Lagrangian is then applied to the computation of the neutral Higgs decays. The sizes of the supersymmetric loop corrections of the neutral Higgs decay widths into χ_ℓ⁰χ_k⁰ (ℓ=1, 2, 3, 4; k=1, 2, 3, 4) are investigated and the supersymmetric loop correction is found to be in the range of ∼10% in significant regions of the parameter space. By including the loop corrections of the other decay channels bmacr b, tmacr t, τ¯τ, cmacr c, and χ_i^-χ_j⁺ (i=1, 2; j=1, 2), the corrections to branching ratios for H_m⁰→χ_ℓ⁰χ_k⁰ can reach as high as 50%. The effects of CP phases on the branching ratio are also investigated. A discussion of the implications of the analysis for colliders is given.