arXiv 1002.11872010-02hep-phhep-ex

$Υ(nS)\to η_b+γ$的辐射衰变研究

Study on the radiative decays of $Υ(nS)\to η_b+γ$

Hong-Wei Ke, Xue-Qian Li, Xiang Liu

备注：: 7 pages, 4 figures; Rectification made and a footnote added

摘要：

在本工作中，我们通过$Υ(nS)\to η_b+γ$的辐射衰变研究了bottomonia家族的自旋单重态$η_b$的特性。衰变宽度的理论估计进行的光前夸克模型（LFQM）。最近CLEO和BaBar合作测量了$\mathcal{B}(Υ(3S)\toγη_b)$和${η_b}$的质量。根据这些数据，我们确定了$Υ(nS)\to η_b+γ$计算中的有关输入参数。特别关注的是$Υ(5S)\to η_b+γ$的过渡。BELLE数据表明，$Υ(5S)\to Υ(2S,1S)+ππ$的宽度比$Υ(4S)\to Υ(2S,1S)+ππ$的宽度大两个数量级，并提出了一些理论解释.其中，非弹性终态相互作用（IFSI）$Υ(5S)\to B\bar B\to Υ(1S)+ππ$可能是一种自然相互作用。如果是这样的话，类似的机制也适用于$Υ(5S)\to B^{(*)}\bar B^{(*)}\to η_b+γ$，精确的测量将作为一个很好的测试是否$Υ(5S)$具有外来成分。我们在LFQM中的计算表明，直接过程$Υ(5S)\toη_b+γ$的速率与$Υ(mS)\toη_b+γ(m=1,2,3,4)$相比并不反常，因此如果IFSI确实适用，则$Υ(5S)\toη_b+γ$的速率应该比其它过程大几个数量级。

英文摘要：

In this work, we investigate the characteristics of the spin-singlet state $η_b$ of the bottomonia family via the radiative decays of $Υ(nS)\to η_b+γ$. The theoretical estimation of the decay widths is carried out in terms of the light-front quark model (LFQM). Recently CLEO and BaBar collaborations have measured $\mathcal{B}(Υ(3S)\toγη_b)$ and the mass of ${η_b}$. In terms of the data we fix the concerned input parameters in our calculations of $Υ(nS)\to η_b+γ$. A special attention is paid on the transition of $Υ(5S)\to η_b+γ$. The BELLE data showed that the width of $Υ(5S)\to Υ(2S,1S)+ππ$ is two orders larger than that of $Υ(4S)\to Υ(2S,1S)+ππ$, thus some theoretical explanations have been proposed. Among them, it is suggested the inelastic final state interaction (IFSI) $Υ(5S)\to B\bar B\to Υ(1S)+ππ$ may be a natural one. If so, a similar mechanism also applies to $Υ(5S)\to B^{(*)}\bar B^{(*)}\to η_b+γ$, the precise measurement would serve as a good test whether $Υ(5S)$ possess exotic components. Our calculation in the LFQM indicates that the rate of the direct process $Υ(5S)\toη_b+γ$ is not anomalous compared to $Υ(mS)\toη_b+γ(m=1,2,3,4)$, thus if the IFSI does apply, the rate of $Υ(5S)\toη_b+γ$ should be larger than the others by orders.

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。

摘要：

英文摘要：

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