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arXiv 0704.3537hep-ph
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RHIC、首阶$k_t$ -因子分解法与次首阶共线法的双射流相关性

Dijet correlations at RHIC, leading-order $k_t$-factorization approach versus next-to-leading order collinear approach

Antoni Szczurek, Anna Rybarska, Gabriela Slipek

摘要:

本文比较了用$k_t$ -因子分解法和次首阶共线-因子分解法计算RHIC能区质子-质子双喷流关联的结果。本文讨论了两股射流横向动量在方位角上的相关性以及在二维空间中的相关性。一些$k_t$ -因子分解子过程是首次在文献中。在$k_t$ -因式分解方法中使用了不同的未积分胶子/部分子分布。结果取决于所使用的乌干达国防军/乌干达人民国防军。对于共线非线性振荡情况,情况主要取决于我们是否考虑任何两个喷流的相关性或相关的领先喷流。在第一种情况下,在$k_t$ -因式分解方法中总结的与软辐射有关的$2 \to 2$贡献在$ϕ\sim π$和等喷流横动量模量处占优势。共线非线性$2 \to 3$贡献占主导地位的$k_t$ -因子化截面在小的相对方位角,以及为非对称的横向动量配置。在第二种情况下,由于简单的运动学约束,NLO贡献在小的相对方位角和/或大的射流横向动量不平衡处消失。对于$k_t$因子分解方法没有这样的限制。所有这一切使得这两种方法相当互补。几个削减的作用进行了讨论和量化。

英文摘要:

We compare results of $k_t$-factorization approach and next-to-leading order collinear-factorization approach for dijet correlations in proton-proton collisions at RHIC energies. We discuss correlations in azimuthal angle as well as correlations in two-dimensional space of transverse momenta of two jets. Some $k_t$-factorization subprocesses are included for the first time in the literature. Different unintegrated gluon/parton distributions are used in the $k_t$-factorization approach. The results depend on UGDF/UPDF used. For collinear NLO case the situation depends significantly on whether we consider correlations of any two jets or correlations of leading jets only. In the first case the $2 \to 2$ contributions associated with soft radiations summed up in the $k_t$-factorization approach dominate at $ϕ\sim π$ and at equal moduli of jet transverse momenta. The collinear NLO $2 \to 3$ contributions dominate over $k_t$-factorization cross section at small relative azimuthal angles as well as for asymmetric transverse momentum configurations. In the second case the NLO contributions vanish at small relative azimuthal angles and/or large jet transverse-momentum disbalance due to simple kinematical constraints. There are no such limitations for the $k_t$-factorization approach. All this makes the two approaches rather complementary. The role of several cuts is discussed and quantified.

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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