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arXiv 0812.3400hep-ex
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在CDF的W+1喷流事件中通过味道改变中性流寻找顶夸克的产生

Search for top-quark production via flavor-changing neutral currents in W+1 jet events at CDF

CDF Collaboration, T. Aaltonen

摘要:

我们报告了第一次使用CDF II探测器收集的ppbar碰撞数据在非标准模型过程u(c)+g -> t中通过变味中性流(FCNC)相互作用寻找顶夸克产生。该数据集对应于2.2/fb的积分亮度。候选事件具有半轻子顶夸克衰变的特征,并通过在模拟事件上训练的人工神经网络分类为信号样或背景样。观测到的判别分布与标准模型预测的判别分布非常一致,并且没有提供FCNC顶夸克产生的证据,导致在95%置信水平下,产生截面sigma(u(c)+g -> t)的贝叶斯上限< 1.8 pb。使用理论预测,我们将横截面极限转换为FCNC分支比的上限:BR(t -> u+g)< 3.9 x 10{-4}$和BR(t -> c+g)< 5.7 x 10^{-3}。

英文摘要:

We report on the first search for top-quark production via flavor-changing neutral-current (FCNC) interactions in the non-standard-model process u(c)+g -> t using ppbar collision data collected by the CDF II detector. The data set corresponds to an integrated luminosity of 2.2/fb. The candidate events feature the signature of semileptonic top-quark decays and are classified as signal-like or background-like by an artificial neural network trained on simulated events. The observed discriminant distribution is in good agreement with the one predicted by the standard model and provides no evidence for FCNC top-quark production, resulting in a Bayesian upper limit on the production cross section sigma (u(c)+g -> t) < 1.8 pb at the 95% confidence level. Using theoretical predictions we convert the cross-section limit to upper limits on FCNC branching ratios: BR (t -> u+g) < 3.9 x 10{-4}$ and BR (t -> c+g) < 5.7 x 10^{-3}.

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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