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arXiv 1003.3926hep-ph
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在Tevatron和LHC上顶夸克对产生和衰变的分布和关联。

Distributions and correlations for top quark pair production and decay at the Tevatron and LHC.

Werner Bernreuther, Zong-Guo Si

摘要:

我们调查了一些可观的是,并将有助于在Tevatron和大型强子对撞机的$\tbart$生产和衰变的探索。为了进行这种分析,我们编制了一个计算机程序,除了对$\tbart$产生和衰变进行非线性光学QCD修正外,还对产生振幅进行了混合弱QCD修正,从而可以研究相关和非相关的$\tbart$事件。本文主要分析和计算了在强、弱规范耦合(NLOW)下,带选择割的次领先阶双轻子$\tbart$末态的观测量。我们计算的顶夸克和$\ell=e,μ$的电荷不对称性,我们比较,在可能的情况下,与实验结果。我们表明,顶夸克自旋关联影响轻子对的不对称性(这还没有被测量到目前为止)的$\sim 7%$。我们确定了几个双轻子角相关,反映了$\tbart$自旋相关,即束,非对角和螺旋度相关,和张角分布(定义在$t$,$\bar t$休息框架)时,应用选择切割。我们的NLOW预测的光束,非对角线,和螺旋度的相关性Tevatron同意最近的测量CDF和D0实验。此外,我们预测这些相关性作为$\mtt$的函数的估计。这些估计可能证明有用的Tevatron和LHC数据分析的早期回合,其中事件的数量可能不会很丰富。此外,我们计算NLOW的规范耦合两个双轻子角相关的实验室框架中定义的,相关和不相关的$\tbart$事件在大型强子对撞机。最后,根据我们的SM结果,我们确定了几个观测值,允许搜索非标准的奇偶校验和CP违反相互作用,特别是与未来的LHC数据。

英文摘要:

We investigate a number of observables that are and will be instrumental in the exploration of $\tbart$ production and decay at the Tevatron and the LHC. For this analysis we made a computer program that incorporates besides the NLO QCD corrections to $\tbart$ production and decay also mixed weak-QCD corrections to the production amplitudes, and that allows for studies of correlated versus uncorrelated $\tbart$ events. In this paper we analyze and compute observables mostly for dileptonic $\tbart$ final states to next-to-leading order in the strong and weak gauge couplings (NLOW), with selection cuts. We calculate charge asymmetries of the top quark and of $\ell=e,μ$ and we compare, where possible, with experimental results. We show that top-quark spin correlations affect a leptonic pair asymmetry (which has not been measured so far) by $\sim 7%$. We determine several dileptonic angular correlations, which reflect $\tbart$ spin correlations, namely the beam, off-diagonal and helicity correlation, and the opening angle distribution (defined in the $t$, $\bar t$ rest frames) when selection cuts are applied. Our NLOW predictions for the beam, off-diagonal, and helicity correlation for the Tevatron agree with recent measurements by the CDF and D0 experiments. In addition we make predictions for estimators of these correlations as functions of $\mtt$. These estimators may prove useful for the Tevatron and also in the early rounds of LHC data-analyses, where the event numbers will probably not be abundant. Furthermore, we compute to NLOW in the gauge couplings two dilepton angular correlations that are defined in the laboratory frame, for correlated and uncorrelated $\tbart$ events at the LHC. Finally, based on our SM results, we identify several observables that allow to search for non-standard parity- and CP-violating interactions, especially with future LHC data.

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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