论文标题
固定目标炭的生产和乳头parton分布
Fixed-target charmonium production and pion parton distributions
论文作者
论文摘要
我们研究了如何使用固定靶标能量的炭刺量来限制PION中的Gluon分布。使用非递归QCD（NRQCD）配方，$ j/ψ$和$ψ（2s）$交叉部分作为纵向动量分数$ x_f $的函数，质子与质子相撞，质子与光目标碰撞，以及$ψ（2s）$ to $ψ（2s）至$ j/ψ$ cross cross cross cross retartios，包括分析。发现颜色octet的长距离矩阵元素对亲parton分布函数（PDFS）具有明显的依赖性。这项研究表明，Pion诱导的炭生产的$ X_F $差分横截面对Pion的Quark和Gluon PDF施加了强大的限制。特别是，具有较大gluon密度的pion PDF可以更好地描述数据。还发现，与$ j/ψ$相比，$ψ（2s）$状态的生产与较大的夸克式贡献有关。
We investigate how charmonium hadroproduction at fixed-target energies can be used to constrain the gluon distribution in pions. Using nonrelativistic QCD (NRQCD) formulation, the $J/ψ$ and $ψ(2S)$ cross sections as a function of longitudinal momentum fraction $x_F$ from pions and protons colliding with light targets, as well as the $ψ(2S)$ to $J/ψ$ cross section ratios, are included in the analysis. The color-octet long-distance matrix elements are found to have a pronounced dependence on the pion parton distribution functions (PDFs). This study shows that the $x_F$ differential cross sections of pion-induced charmonium production impose strong constraints on the pion's quark and gluon PDFs. In particular, the pion PDFs with larger gluon densities provide a significantly better description of the data. It is also found that the production of the $ψ(2S)$ state is associated with a larger quark-antiquark contribution, compared with $J/ψ$.
