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arXiv 1801.03582hep-phhep-ex
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探索$Υ(4S,5S,6S) \to h_b(1P)η$隐底强子跃迁

Exploring the $Υ(4S,5S,6S) \to h_b(1P)η$ hidden-bottom hadronic transitions

Yawei Zhang, Gang Li

摘要:

最近,Belle合作组织报道了具有出乎意料的大分支比的自旋翻转跃迁$Υ(4S) \to h_b(1P)η$的测量:$\mathcal{B}(Υ(4S) \to h_b(1P)η) =(2.18\pm 0.11\pm 0.18)\times 10^{-3}$。如此大的分支分数与自旋翻转的预期抑制相矛盾。在这项工作中,我们研究了中间底介子环引起的效应,并指出这些效应是非常重要的。利用有效拉格朗日方法(ELA),我们发现$Υ(4S) \to h_b(1P)η$上的实验数据可以与合理的输入相适应。然后,我们探索衰变$Υ(5S,6S)\to h_b(1P)η$,发现这两个通道也有相当大的分支分数。我们也在非相对论有效场论(NREFT)的框架下计算了这些过程。对于衰变$Υ(4S) \to h_b(1P) η$,NREFT结果与ELA结果具有相同的数量级,但比ELA结果小$2$至$5$倍。对于衰变$Υ(5S, 6S) \to h_b(1P) η$,NREFT结果比ELA结果小大约一个数量级。我们建议将来的Belle-Ⅱ实验寻找$Υ(5S, 6S)\to h_b(1P) η$衰变,这将有助于理解过渡机制。

英文摘要:

Recently, Belle Collaboration has reported the measurement of the spin-flipping transition $Υ(4S) \to h_b(1P)η$ with an unexpectedly large branching ratio: $\mathcal{B}(Υ(4S) \to h_b(1P)η) =(2.18\pm 0.11\pm 0.18)\times 10^{-3}$. Such a large branching fraction contradicts with the anticipated suppression for the spin flip. In this work, we examine the effects induced by intermediate bottomed meson loops and point out that these effects are significantly important. Using the effective Lagrangian approach (ELA), we find the experimental data on $Υ(4S) \to h_b(1P)η$ can be accommodated with the reasonable inputs. We then explore the decays $Υ(5S,6S)\to h_b(1P)η$ and find that these two channels also have sizable branching fractions. We also calculate these these processes in the framework of nonrelativistic effective field theory (NREFT). For the decays $Υ(4S) \to h_b(1P) η$, the NREFT results are at the same order of magnitude but smaller than the ELA results by a factor of $2$ to $5$. For the decays $Υ(5S, 6S) \to h_b(1P) η$ the NREFT results are smaller than the ELA results by approximately one order of magnitude. We suggest future experiment Belle-II to search for the $Υ(5S, 6S)\to h_b(1P) η$ decays which will be helpful to understand the transition mechanism.

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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