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arXiv 0910.4155hep-ph
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在B工厂寻找$e^+e^-\to γ+ X$中的$C=+$粲鎓和底鎓态

Search for $C=+$ charmonium and bottomonium states in $e^+e^-\to γ+ X$ at B factories

Dan Li, Zhi-Guo He, Kuang-Ta Chao

摘要:

我们研究了在B工厂用$X=η_c(nS)$(n= 1,2,3),$χ_{cJ}(mP)$(m= 1,2),和$^1D_2(1D)$生产$C=+$粲偶素状态$X$(在$e^+e^-\to γ+ X$中).在S波和P波情况下,在非相对论QCD(NRQCD)框架下计算了具有单圈QCD修正的树QED的贡献,而在D波情况下只考虑树QED的贡献。我们发现,在大多数情况下,QCD修正是负的和温和的,相反的情况下,双粲偶素生产$e^+e^-\to J/ψ+ X$,在那里的QCD修正是积极的和大的在大多数情况下。我们还发现,即使在考虑了负QCD修正后,$e^+e^-\to γ+ X$中某些态的产生截面仍比$e^+e^-\to J/ψ+ X$中的大一个数量级。因此,我们认为,在B工厂中搜索$e^+e^-\to γ+ X$中的X(3872),X(3940),Y(3940)和X(4160)可能有助于澄清这些状态的性质。为了完整起见,还讨论了$e^+e^-$湮灭过程中底鎓态的产生。

英文摘要:

We study the production of $C=+$ charmonium states $X$ in $e^+e^-\to γ+ X$ at B factories with $X=η_c(nS)$ (n=1,2,3), $χ_{cJ}(mP)$ (m=1,2), and $^1D_2(1D)$. In the S and P wave case, contributions of tree-QED with one-loop QCD corrections are calculated within the framework of nonrelativistic QCD(NRQCD) and in the D-wave case only the tree-QED contribution are considered. We find that in most cases the QCD corrections are negative and moderate, in contrast to the case of double charmonium production $e^+e^-\to J/ψ+ X$, where QCD corrections are positive and large in most cases. We also find that the production cross sections of some of these states in $e^+e^-\to γ+ X$ are larger than that in $e^+e^-\to J/ψ+ X$ by an order of magnitude even after the negative QCD corrections are included. So we argue that search for the X(3872), X(3940), Y(3940), and X(4160) in $e^+e^-\to γ+ X$ at B factories may be helpful to clarify the nature of these states. For completeness, the production of bottomonium states in $e^+e^-$ annihilation is also discussed.

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