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arXiv 2304.04552hep-ph
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利用软胶子因子化解决粲夸克偶素强产生的负截面问题

Resolving negative cross section of quarkonium hadroproduction using soft gluon factorization

An-Ping Chen, Yan-Qing Ma, Ce Meng

AI总结:

针对非相对论QCD因子化下大横动量$χ_{cJ}$强产生截面为负的问题,研究提出在软胶子因子化框架中将负截面相关项因子化为非微扰软胶子分布函数,自然解决负截面问题,且全横动量区间预测为正,$ψ(2S)$产生无此问题。

摘要:

研究发现,采用非相对论QCD因子化方法时,大$p_T$下$χ_{cJ}$强产生截面的预测值可能为负。负截面源于$^{3}\text{P}_{J}^{[1]}$道中与正函数成正比的项,这些项是匹配$^{3}\text{P}_{J}^{[1]}$短程系数时红外减除的剩余部分。本文发现,在软胶子因子化(SGF)框架下,上述项可被因子化为非微扰的$^{3}\text{S}_{1}^{[8]}$软胶子分布函数,因此该问题可在SGF中自然解决。通过合理选取非微扰参数,SGF确实能在整个$p_T$区间给出$χ_{cJ}$产生率的正预测。本文还讨论了$ψ(2S)$的产生,其不存在负截面问题。

英文摘要:

It was found that, using nonrelativistic QCD factorization, the predicted $χ_{cJ}$ hadroproduction cross section at large $p_T$ can be negative. The negative cross sections originate from terms proportional to plus function in ${^{3}\hspace{-0.6mm}P_{J}^{[1]}}$ channels, which are remnants of the infrared subtraction in matching the ${^{3}\hspace{-0.6mm}P_{J}^{[1]}}$ short-distance coefficients. In this article, we find that the above terms can be factorized into the nonperturbative ${^{3}\hspace{-0.6mm}S_{1}^{[8]}}$ soft gluon distribution function in the soft gluon factorization (SGF) framework. Therefore, the problem can be naturally resolved in SGF. With an appropriate choice of nonperturbative parameters, the SGF can indeed give positive predictions for $χ_{cJ}$ production rates within the whole $p_T$ region. The production of $ψ(2S)$ is also discussed, and there is no negative cross section problem.

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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