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arXiv 0904.3206hep-ph
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TEVATRON强子产生的$J/ψ$极化的主导自旋翻转效应

Dominant Spin-Flip Effects for the Hadronic Produced $J/ψ$ Polarization at TEVATRON

Xing-Gang Wu, Zhen-Yun Fang

备注：
19 pages, 5 figures. References added. Revised version to be published in Phys.Rev.D
发表信息：
Phys.Rev.D80:034010,2009
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摘要：

本文系统地研究了在TEVATRON运行II（碰撞能1.96TeV，快度截断$|y^{J/ψ}|<0.6$）下，$J/ψ$直接和瞬发极化的主导自旋翻转效应，特别是对$(c\bar{c})_8[^3S_1]$向$J/ψ$跃迁的自旋翻转效应进行了详细的讨论。结果表明，自旋翻转效应总是会稀释$J/ψ$的极化，适当选择$a_{0,1}$和$c_{0,1,2}$参数，可以在一定程度上解决$J/ψ$的极化难题.在大横向动量$p_t$时，提示$J/ψ$的$α$减少了$f_0 = v^2$的$\sim50%$和$f_0=1$的$\sim80%$。我们还研究了从$b$ -衰变的间接$J/ψ$偏振，然而，这是轻微的影响，由相同的自旋翻转效应，然后将提供一个更好的平台，以确定颜色八重矩阵元素。

英文摘要：

Dominant spin-flip effects for the direct and prompt $J/ψ$ polarizations at TEVATRON run II with collision energy 1.96 TeV and rapidity cut $|y^{J/ψ}|<0.6$, have been systematically studied, especially, the spin-flip effect for the transition of $(c\bar{c})_8[^3S_1]$ into $J/ψ$ has been carefully discussed. It is found that the spin-flip effect shall always dilute the $J/ψ$ polarization, and with a suitable choice of the parameters $a_{0,1}$ and $c_{0,1,2}$, the $J/ψ$ polarization puzzle can be solved to a certain degree. At large transverse momentum $p_t$, $α$ for the prompt $J/ψ$ is reduced by $\sim50%$ for $f_0 = v^2$ and by $\sim80%$ for $f_0=1$. We also study the indirect $J/ψ$ polarization from the $b$-decays, which however is slightly affected by the same spin-flip effect and then shall provide a better platform to determine the color-octet matrix elements.

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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