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arXiv 1609.08413hep-ph
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J/ $ψ$和$ψ'$介子在LHC上的包容产生

Inclusive production of J/$ψ$ and $ψ'$ mesons at the LHC

Anna Cisek, Antoni Szczurek

摘要:

本文利用非积分胶子分布(UGDF),采用NRQCD $k_{t}$ -因子化方法,讨论了LHC质子-质子碰撞中$J/ψ$介子的瞬时产生。我们包括直接颜色单态生产($gg \to J/ψ$ g)以及从$χ_{c} \to J/ψγ$和$ψ' \to J/ψX$进料。衰变介子($χ_{c}$或$ψ'$)的产生也在NRQCD $k_{t}$ -因子分解中计算。$gg \to J/ψ$、$gg \to ψ'$和$gg \to χ_{c}$的相应矩阵元素包括在$r=0$处夸克偶素的非相对论性空间波函数的参数,这些参数取自文献中的势模型。我们得到的比例相应的横截面为$χ_{c}(2)$ - $χ_{c}(1)$更接近实验数据比在最近的分析。计算了$J/ψ$和$ψ'$快度的微分分布,并与ALICE和LHCb合作的实验数据进行了比较。我们讨论了在向前/向后的rapidities胶子饱和效应的可能发病。人们可以描述的实验数据$J/ψ$生产模型的不确定性与颜色单组分。因此,我们的理论结果只留下一个相对较小的空间的颜色八隅体的贡献。

英文摘要:

We discuss the prompt production of $J/ψ$ mesons in proton-proton collisions at the LHC within a NRQCD $k_{t}$-factorization approach using Kimber-Martin-Ryskin (KMR) unintegrated gluon distributions (UGDF). We include both direct color-singlet production ($gg \to J/ψ$g) as well as a feed-down from $χ_{c} \to J/ψγ$ and $ψ' \to J/ψX$. The production of the decaying mesons ($χ_{c}$ or $ψ'$)is also calculated within NRQCD $k_{t}$-factorization. The corresponding matrix elements for $gg \to J/ψ$, $gg \to ψ'$ and $gg \to χ_{c}$ include parameters of the nonrelativistic spatial wave functions of quarkonia at $r=0$, which are taken from potential models from the literature. We get the ratio of the corresponding of the cross sections for $χ_{c}(2)$-to-$χ_{c}(1)$ much closer to experimental data than obtained in recent analyses. Differential distributions in rapidity of $J/ψ$ and $ψ'$ are calculated and compared to experimental data of the ALICE and LHCb collaborations. We discuss possible onset of gluon saturation effects at forward/backward rapidities. One can describe the experimental data for $J/ψ$ production within model uncertainties with color-singlet component only. Therefore our theoretical results leave only a relatively small room for the color-octet contributions.

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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