Search for a low-mass Higgs boson (A0) at BABAR

The BABAR Collaboration has performed three searches for a light Higgs boson, A0, in radia-tive Upsilon (ϒ) decays: ϒ (3S) → γA0, A0 → τ+τ−; ϒ (nS) → γA0, A0 → µ+µ − (n = 2,3); and ϒ (3S) → γA0, A0 → invisible. Such a Higgs boson (A0) appears in the Next-to-Minimal Supersymmetric extensions of the Standard Model, where a light CP-odd Higgs boson couples strongly to b-quarks. The searches are based on data samples that consist of 122 × 106 ϒ (3S) and 99 × 106 ϒ (2S) decays, collected by the BABAR detector at the SLAC National Accelerator Laboratory. The searches reveal no evidence for an A0, and product of branching fractions upper limits, at 90 % C.L., of (1.5 − 16) × 10−5, (0.44 − 44) × 10−6, and (0.7 − 31) × 10−6 were ob-tained for these searches, respectively. Also, we set the upper limits B(ηb → τ+τ−) < 8 % and B(ηb → µ+µ−) < 0.9%