Pair production of heavy quarkonium and B c ( * ) mesons at hadron colliders
Pair production of heavy quarkonium and B c ( * ) mesons at hadron colliders
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DOI：
10.1103/physrevd.80.014020
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发表时间：
2009-03
影响因子：
5
通讯作者：
Rong Li;Yu-Jie Zhang;K. Chao
中科院分区：
文献类型：
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作者：
Rong Li;Yu-Jie Zhang;K. Chao
我们研究了大型强子对撞机上彩色单重态机制（CSM）中$S$波重夸克素的配对产生，并估计了彩色八位组机制（COM）中胶子碎片过程的贡献以进行比较。利用先前在前导计算中提取的矩阵元素，数值结果表明大型强子对撞机的配对生产过程的生产率相当大。当 ${p}_{t}$ 小于约 10 GeV 时，CSM 中双 $J/\ensuremath{\psi}$ 产量的 ${p}_{t}$ 分布优于 COM 中的分布。对于double $\ensuremath{\Upsilon}$的产生，COM的贡献总是大于CSM的贡献。 CSM 和 COM 对大 ${p}_{t}$ 区域中 ${p}_{t}$ 分布的理论预测存在巨大差异，这有助于阐明 COM 对夸克素生产的影响。我们还研究了$S$波${B}_{c}$和${B}_{c}^{*}$介子的配对产生，这些过程的测量对于测试CSM和提取${B}_{c}$和${B}_{c}^{*}$介子的长距离矩阵元素很有用。除了数值计算之外，还给出了所有这些过程的生产微分截面的解析表达式。
We investigate the pair production of $S$-wave heavy quarkonium at the LHC in the color-singlet mechanism (CSM) and estimate the contribution from the gluon fragmentation process in the color-octet mechanism (COM) for comparison. With the matrix elements extracted previously in the leading-order calculations, the numerical results show that the production rates are quite large for the pair production processes at the LHC. The ${p}_{t}$ distribution of double $J/\ensuremath{\psi}$ production in the CSM is dominant over that in the COM when ${p}_{t}$ is smaller than about 10 GeV. For the production of double $\ensuremath{\Upsilon}$, the contribution of the COM is always larger than that in the CSM. The large differences in the theoretical predictions between the CSM and COM for the ${p}_{t}$ distributions in the large ${p}_{t}$ region are useful in clarifying the effects of COM on the quarkonium production. We also investigate the pair production of $S$-wave ${B}_{c}$ and ${B}_{c}^{*}$ mesons, and the measurement of these processes is useful to test the CSM and extract the long-distance matrix elements for the ${B}_{c}$ and ${B}_{c}^{*}$ mesons. Aside from numerical calculations, analytical expressions for the production differential cross sections of all these processes are also given.