Summary: | 碩士 === 國立臺灣大學 === 物理研究所 === 101 === We report a search for a bottomonium counterpart of exotic charmonium state X(3872), denoted as Xb throughout this thesis. The target decay channel is Xb→Υ(1S)π+π−→μ+μ-π+π−. An integrated luminosity of 20.65/fb at proton-proton collision at sqrt{s}=8 TeV is analyzed. In the search phase space, |y_{Xb}| < 2.0, p_{T,Xb} > 13.5 GeV/c^2, and 10 < M_{Xb} < 11 GeV/c^2, the maximum local significance is 2.6 sigma, which equals to 0.8 sigma global significance. The upper limit at 95% confidence level is settled to be 0.8-4.6% (depend on the mass of Xb) as the cross section of Υ(1S)→Υ(1S)π+π−.
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