论文标题
原子质量,Bjorken的变量和夸克传输系数在Drell-YAN过程中的质子质子的质量依赖性
Atomic mass, Bjorken variable and scale dependence of quark transport coefficient in Drell-Yan process for proton incident on nucleus
论文作者
论文摘要
通过在没有固定目标的Drell-YAN实验数据和基于BDMPS形式主义的淬火分析表达的情况下确定的核部分分布,对Fermilab E906和E866协作的Drell-YAN差分横截面比率进行了近距离领先的订单分析。发现只有Parton分布的核效应的计算结果与E866和E906实验数据一致。在核Drell-Yan反应中,进入的Parton能量损失效应不能忽略。预测的结果表明,使用夸克传输系数为恒定,夸克运输系数的目标核几何效应引起的抑制约为19.24%。结果表明,我们应该考虑在研究核靶标的drell-yan反应时的靶核几何效应。根据Bjorken变量和夸克传输系数的比例依赖性,将原子质量依赖性纳入了。夸克传输系数是根据原子质量,bjorken变量$ x_2 $和比例$ q^2 $的函数确定的。确定的常数因子$ \ hat {q} _0 $ QUARK运输系数为$ 0.061 \ pm0.004 {\ rm Gev^2/fm} $。发现原子质量依赖对冷核物质的夸克运输系数中的常数因子$ \ hat {q} _0 $具有显着影响。
By means of the nuclear parton distributions determined without the fixed-target Drell-Yan experimental data and the analytic expression of quenching weight based on BDMPS formalism, a next-to-leading order analyses are performed on the Drell-Yan differential cross section ratios from Fermilab E906 and E866 Collaborations. It is found that the calculated results with only the nuclear effects of parton distribution are not in agreement with the E866 and E906 experimental data. The incoming parton energy loss effect can not be ignored in the nuclear Drell-Yan reactions. The predicted results indicate that with the quark transport coefficient as a constant, the suppression due to the target nuclear geometry effect is approximately 19.24% for the quark transport coefficient. It is shown that we should consider the target nuclear geometry effect in studying the Drell-Yan reaction on nuclear targets. On the basis of Bjorken variable and scale dependence of the quark transport coefficient, the atomic mass dependence is incorporated. The quark transport coefficient is determined as a function of the atomic mass, Bjorken variable $x_2$ and scale $Q^2$ by the global fit of the experimental data. The determined constant factor $\hat{q}_0$ of the quark transport coefficient is $0.061\pm0.004 {\rm GeV^2/fm}$. It is found that the atomic mass dependence has a remarkable impact on the constant factor $\hat{q}_0$ in the quark transport coefficient in cold nuclear matter.