J/ψ polarization at the Tevatron and the LHC: nonrelativistic-QCD factorization at the crossroads.
J/ψ polarization at the Tevatron and the LHC: nonrelativistic-QCD factorization at the crossroads.
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DOI：
10.1103/physrevlett.108.172002
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发表时间：
2012-01
影响因子：
8.6
通讯作者：
M. Butenschoen;B. Kniehl
中科院分区：
文献类型：
--
作者：
M. Butenschoen;B. Kniehl
我们在非相对论量子色动力学的因式分解形式中研究了 J/ψ 粒子产生的偏振可观测量。我们还通过提供中间 (3)P(J)([8]) 颜色八位组状态的贡献来完成相对论校正的现有知识，结果证明这是非常重要的。利用先前通过对非偏振 J/ψ 产生的实验数据进行全局拟合提取的彩色八位组长距离矩阵元素，我们提供了螺旋性和 Collins-Soper 框架的理论预测，并将它们与费米实验室 Tevatron I 和 II 的 CDF 以及 CERN LHC 的 ALICE 获取的数据进行比较。前导分析中常见的臭名昭著的 CDF J/ψ 偏振异常在量子水平上仍然存在，而大型强子对撞机的情况看起来很有希望，这必将带来最终的澄清。
We study the polarization observables of J/ψ hadroproduction at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics. We complete the present knowledge of the relativistic corrections by also providing the contribution due to the intermediate (3)P(J)([8]) color-octet states at this order, which turns out to be quite significant. Exploiting the color-octet long-distance matrix elements previously extracted through a global fit to experimental data of unpolarized J/ψ production, we provide theoretical predictions in the helicity and Collins-Soper frames and compare them with data taken by CDF at Fermilab Tevatron I and II and by ALICE at CERN LHC. The notorious CDF J/ψ polarization anomaly familiar from leading-order analyses persists at the quantum level, while the situation looks promising for the LHC, which is bound to bring final clarification.