2013/07/17 by Vindhyawasini Prasad, Prasad, Vindhyawasini
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #hep-ex
paper · pdf · doi:10.48550/arxiv.1307.4560
138 pages, This is a thesis
arxiv created 2013/10/07 · arxiv updated 2013/10/09
We search for di-muon decays of a low-mass Higgs boson (A0) in the fully reconstructed decay chain of Υ(2S,3S) → \pipiΥ(1S), Υ(1S) → \g A0, A0 → \mumu. The A0 is predicted by several extensions of the Standard Model (SM), including the Next-to-Minimal Supersymmetric Standard Model (NMSSM). NMSSM introduces a \CP-odd light Higgs boson whose mass could be less than 10 \gevcc. The data samples used in this analysis contain 92.8 × 106 Υ(2S) and 116.8 × 106 Υ(3S) events collected by the \babar detector. The Υ(1S) sample is selected by tagging the pion pair in the Υ(2S, 3S) → π+π-Υ(1S) transitions. We find no evidence for A0 production and set 90% confidence level (C.L.) upper limits on the product branching fraction B(Υ(1S) → \g A0) × B(A0 → \mumu) in the range of (0.28 - 9.7)× 10-6 for 0.212 ≤ mA0 ≤ 9.20 \gevcc. We also combine our results with previous \babar results of Υ(2S,3S) → \g A0, A0 → \mumu to set limits on the effective coupling (fΥ) of the \b-quark to the A0, fΥ2 × B(A0 → \mumu), at the level of (0.29 - 40)× 10-6 for 0.212 ≤ mA0 ≤ 9.2 GeV/c2.