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arXiv 0802.0649hep-phhep-ex
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剧变系统中奇异态存在的可能性

Possibility of Exotic States in the Upsilon system

Marek Karliner, Harry J. Lipkin

摘要:

最近来自Belle的数据显示了异常大的部分宽度Uppermont(5S)--> Uppermont(1 S)pi^+pi^-和Uppermont(5S)--> Uppermont(2S)pi^+ pi^-。Belle在psi' pi^+谱中也报道了Z(4430)窄共振,它具有预期的性质。(cbar c u dbar)带电等矢量四夸克态T^{+-}_cc底部扇区的类似态T^{+-}可能介导Upperdum系统中的巨大级联衰变,Upperdum(mS)--> T^{+-}_bb pi^{-+} --> Upperdum(nS)pi^+ π^-,四夸克-π介子中间态我们建议在这些衰变中寻找(bbar b u dbar)四夸克态,作为Uppersons(1 S)pi或Uppersons(2S)pi系统不变质量的峰值。(bbar b u sbar)四夸克态可以作为一个峰出现在所观察到的衰变Uppersons(5S)--> Uppersons(1 S)K^+ K^-中,它是Uppersons(1 S)K系统不变质量的一个峰。我们回顾的模型表明,这些四夸克是低于两个重介子阈值,但分别高于Uppermos pi pi和Uppermos K Kbar阈值。

英文摘要:

Recent data from Belle show unusually large partial widths Upsilon(5S) --> Upsilon(1S) pi^+pi^- and Υ(5S) --> Υ(2S) pi^+ pi^-. The Z(4430) narrow resonance also reported by Belle in psi' pi^+ spectrum has the properties expected of a (cbar c u dbar) charged isovector tetraquark T^{+-}_cc The analogous state T^{+-} in the bottom sector might mediate anomalously large cascade decays in the Upsilon system, Upsilon(mS) --> T^{+-}_bb pi^{-+} --> Upsilon(nS) pi^+ π^-, with a tetraquark-pion intermediate state. We suggest looking for the (bbar b u dbar) tetraquark in these decays as peaks in the invariant mass of Upsilon(1S) pi or Upsilon(2S) pi systems. The (bbar b u sbar) tetraquark can appear in the observed decays Upsilon(5S) --> Upsilon(1S) K^+ K^- as a peak in the invariant mass of Upsilon(1S) K system. We review the model showing that these tetraquarks are below the two heavy meson threshold, but respectively above the Upsilon pi pi and Upsilon K Kbar thresholds.

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