论文标题
区分色彩与颜色Quckonium生产的挑战
A Challenge for Discrimination of Color-Singlet versus Color-Octet Quarkonium Production
论文作者
论文摘要
在强子山着壁上生产Quarkonium的确切机制仍然是一个悬而未决的问题。在非相关性量子染色体动力学中，可以将Quarkonium生产横截面分为短途，扰动贡献和通用，非扰动，长距离矩阵元素，然后对重夸克对的量子数量求和。原则上，在短距离时，重夸克对可以处于颜色或颜色octet状态，并且希望建立相对贡献以与数据进行比较并在不同的实验环境中进行预测。从用于色彩单曲和颜色octet产生的最低级扰动矩阵元素的明确形式，我们表明，最佳可观察到的相位空间歧视的结构，可能性比率，可能性比，可能是对重夸克对的角度动量的依赖性。这构成了一个可观察到的单一强大歧视构建的障碍，可以应用于任意Quarkonium状态的生产。
The precise mechanism for production of quarkonium at hadron colliders is still an open question. Within non-relativistic quantum chromodynamics, quarkonium production cross sections can be factorized into short-distance, perturbative contributions and universal, non-perturbative, long-distance matrix elements, and then summed over quantum numbers of the heavy quark pair. In principle, at short-distances, the heavy quark pair can be either in a color-singlet or color-octet state, and it is desirable to establish the relative contributions to compare with data and to make predictions in different experimental environments. From the explicit form of the lowest-order perturbative matrix elements for color-singlet and color-octet production, we show that the structure of the optimal observable for discrimination on phase space, the likelihood ratio, has strong dependence on the angular momentum state of the heavy quark pair. This presents an obstruction for construction of a single, robust discrimination observable that can be applied to production of an arbitrary quarkonium state.
