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arXiv 1108.4845hep-ex
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用CMS实验研究pp碰撞中夸克偶素的产生

Quarkonium production in pp collisions at 7 TeV with the CMS experiment

Bora Akgün

摘要:

利用大型强子对撞机(LHC)的CMS实验研究了\surds = 7 TeV的pp碰撞中J/ψ和Y介子的产生。J/μ测量是基于对应于314 nb ^{-1}的积分亮度的双μ子样本。在三个快度范围内,J/ψ微分截面是J/ψ横动量的函数。一个适合的衰变长度分布是用来分离的提示从非提示(b强子J/π)组件。在横动量为6.5~30 GeV/c的J/π和快度为|y| <2.4的范围内积分,测得的截面乘以双μ子衰变分支分数为70.9 \pm 2.1(stat.)\pm 3.0(系统)\pm 7.8(流明)假设非极化产生,瞬发J/π介子的nb = 26.0 \pm 1.4(stat.)\pm 1.6(系统)\pm 2.9(流明)b-强子衰变产生的J/π介子。该测量基于对应于积分光度3.1 \pm 0.3 pb ^{-1}的双μ子样本。在|y| <2的快度范围内积分,我们发现双μ子的产生截面和分支分数的乘积为7.37 \pm 0.13(stat.)^ {+0.61}_{-0.42}(系统)\pm 0.81(亮度。)NB.这个截面是在假设产生非极化的双(1S)的情况下得到的。如果晶体(1S)产生极化是完全横向的或完全纵向的,则截面改变约20%。

英文摘要:

The production of J /ψ and Υ mesons is studied in pp collisions at \surds = 7 TeV with the CMS experiment at the LHC. The J /ψ measurement is based on a dimuon sample corresponding to an integrated luminosity of 314 nb^{-1}. The J /ψ differential cross section is determined, as a function of the J/ψ transverse momentum, in three rapidity ranges. A fit to the decay length distribution is used to separate the prompt from the non-prompt (b hadron to J/ψ) component. Integrated over the J /ψ transverse momentum from 6.5 to 30 GeV/c and over rapidity in the range |y| < 2.4, the measured cross sections, times the dimuon decay branching fraction, are 70.9 \pm 2.1(stat.) \pm 3.0(syst.) \pm 7.8(lumi.) nb for prompt J /ψ mesons, assuming unpolarized production, and 26.0 \pm 1.4(stat.) \pm 1.6(syst.) \pm 2.9(lumi.) nb for J /ψ mesons from b-hadron decays. The Υ measurement is based on a dimuon sample corresponding to an integrated luminosity 3.1 \pm 0.3 pb^{-1}. Integrated over the rapidity range |y| < 2, we find the product of the Υ(1S) production cross section and branching fraction to dimuons to be 7.37 \pm 0.13(stat.)^{+0.61}_{-0.42}(syst.) \pm 0.81(lumi.) nb. This cross section is obtained assuming unpolarized Υ(1S) production. If the Υ(1S) production polarization is fully transverse or fully longitudinal, the cross section changes by about 20 %.

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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