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arXiv 1202.2178hep-phhep-ex
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$Z_b(10610)$是一种分子状态吗?

Is $Z_b(10610)$ a Molecular State?

Hong-Wei Ke, Xue-Qian Li, Yan-Liang Shi, Guo-Li Wang, Xu-Hao Yuan

摘要:

自然界中是否真的存在分子态,长期以来一直存在争议。在最近的实验中观察到了一些新的共振态,它们似乎是奇异的结构,其中一些被认为是分子态。最近对$Z_b(10610)[(10608.4\pm 2.0)$ MeV]和$Z_b(10650)[(10653.2\pm 1.5)$ MeV]的观测鼓励了对多夸克态的解释。在Beter-Salpeter(BS)方法中,我们研究了两个重介子通过交换轻介子形成分子态的可能性。结果表明,当$σ-$交换的贡献相当小时,即当$σ$与介子$g_σ$的耦合取文献中给出的值时,两个重介子可以形成一个同位旋单重态(I=0),但不能形成一个同位旋三重态(I=1).由此我们得出结论:新观测到的$Z_b(10610)$不应该是分子态,而应该是四夸克态,最多是分子态在物理共振$Z_b(10610)$中所占的比例很小。

英文摘要:

Whether molecular states indeed exist in nature has been disputed for a long time. Several new resonances have been observed in the recent experiments and they seem to be of exotic structures and some of them have been proposed to be molecular states. The very recent observation of $Z_b(10610)[(10608.4\pm 2.0)$ MeV] and $Z_b(10650)[(10653.2\pm 1.5)$ MeV] encourages the interpretation of multi-quark states. In the Beter-Salpeter (BS) approach, we study the possibility if two heavy mesons can form a molecular state by exchanging light mesons. Our results indicate that two heavy mesons can form an isospin singlet (I=0) bound state but cannot form an isospin triplet (I=1) when the contribution of $σ-$ exchange is reasonably small, i.e. as the coupling of $σ$ with mesons $g_σ$ takes the value given in previous literatures. Thus we conclude that the newly observed $Z_b(10610)$ should not be a molecular state, but a tetraquark state instead, at most, the fraction of the molecular state in the physical resonance $Z_b(10610)$ is tiny.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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