arXiv 1002.39872010-02hep-phhep-ex

在强子对撞机上对$χ_{cJ}$产生的QCD辐射修正

QCD radiative corrections to $χ_{cJ}$ production at hadron colliders

Yan-Qing Ma, Kai Wang, Kuang-Ta Chao

备注：: Version published in PRD (Rapid Communication); Title changed as suggested by journal editor; in Fig.5 predictions and data at Tevatron (as well as at LHC) are shown; no changes for physical results
发表信息：: Phys.Rev.D83:111503,2011
DOI：: 10.1103/PhysRevD.83.111503

摘要：

澄清了粲偶素生产中存在的问题，即现有理论不能解释观测到的$χ_{cJ}$（J= 0，1，2）截面和比率$R_{χ_c}=σ_{χ_{c2}}/σ_{χ_{c1}}\approx 0.75$（与自旋计数值5/3相反），我们研究了非相对论QCD中完全次领先级辐射修正，并且发现在高$p_T$下，$^3P_J^{[1]}$的次前导阶贡献比前导阶更重要，并且$^3P_1^{[1]}$比$^3P_2^{[1]}$降低得更慢，这意味着$R_{χ_c}$之谜有了一个自然的解释。通过对$R_{χ_c}$的拟合，发现预测的$χ_{cJ}$的截面与实验数据相吻合。结果表明，色八重态的贡献是至关重要的，从而提供了一个独特的测试重夸克偶素的生产机制。估计$χ_{cJ}$对促进$J/ψ$产生的反馈贡献是相当大的，在$p_T=20$ GeV下约为$30-40%$。还预测了大型强子对撞机上会产生$χ_{cJ}$（J= 0，1，2）。

英文摘要：

To clarify the outstanding problem in charmonium production that existing theories cannot explain the observed cross sections of $χ_{cJ}$ (J=0,1,2) and ratio $R_{χ_c}=σ_{χ_{c2}}/σ_{χ_{c1}}\approx 0.75$ (in contrast to the spin counting value 5/3) at the Tevatron, we study the complete next-to-leading order radiative corrections in nonrelativistic QCD, and find next-to-leading order contributions of $^3P_J^{[1]}$ are more important than leading order at high $p_T$, and $^3P_1^{[1]}$ decreases slower than $^3P_2^{[1]}$, implying a natural explanation for the $R_{χ_c}$ puzzle. By fitting $R_{χ_c}$, the predicted cross sections of $χ_{cJ}$ are found to agree with data. The result indicates color-octet contribution is crucially needed, thus providing a unique test for heavy quarkonium production mechanisms. Feed-down contributions of $χ_{cJ}$ to prompt $J/ψ$ production are estimated to be substantial, about $30-40%$ at $p_T=20$ GeV. Production of $χ_{cJ}$ (J=0,1,2) at the LHC is also predicted.

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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