Search for a Light Higgs Boson Decaying to Two Gluons or ss̅ in the Radiative Decays of ϒ(1s)

We search for the decay ϒ(1s) → γA⁰, A⁰ → gg or ss̅, where A⁰ is the pseudoscalar light Higgs boson predicted by the next-to-minimal supersymmetric Standard Model. We use a sample of (17.6 ± 0.3) x10⁶ ϒ(1s) mesons produced in the BABAR experiment via e⁺e⁻ → ϒ(2s) → π⁺π⁻ ϒ(1s). We see no significant signal and set 90%-confidence-level upper limits on the product branching fraction ℬ(ϒ(1s) → γA⁰) ⋅ ℬ(A⁰ → gg or ss̅) ranging from 10⁻⁶ to 10⁻² for A⁰ masses in the range 0.5-9.0 GeV/c².