Search for a light Higgs boson decaying to two gluons or ss[over ̄] in the radiative decays of Υ(1S)

We search for the decay Υ(1S)→γA0, A0→gg or ss ̄, 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)×106 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→ggorss ̄) ranging from 10-6 to 10-2 for A0 masses in the range 0.5-9.0GeV/c2.