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arXiv 1303.3239hep-ex
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在sqrt(s)= 7 TeV处测量矢量玻色子和顶夸克-反夸克对的关联产生

Measurement of associated production of vector bosons and top quark-antiquark pairs at sqrt(s) = 7 TeV

CMS Collaboration

摘要:

首次测量了sqrt(s)= 7 TeV质子-质子碰撞中顶夸克-反夸克对的矢量玻色子产生。这些结果是基于2011年大型强子对撞机CMS探测器记录的对应于5.0毫微微巴的积分亮度的数据集。测量是在两个独立的通道中进行的,通过对t t-bar Z事件的三轻子分析和对t t-bar V(V = W或Z)事件的同号双轻子分析。在三轻子通道中,直接测量了t t-杆Z的截面σ(t t-杆Z)= 0.28 + 0.14/-0.11(stat)+0.06/-0.03(syst)pb。在双轻子通道中,测量t t-巴V的截面得到σ(t t-巴V)= 0.43 + 0.17/-0.15(stat)+0.09/-0.07(syst)pb。这些测量值与背景假设的显著性分别为3.3和3.0标准差,并且在不确定性范围内与相应的次前阶预测值0.137 + 0.012/-0.016和0.306 + 0.031/-0.053 pb相容。

英文摘要:

The first measurement of vector-boson production associated with a top quark-antiquark pair in proton-proton collisions at sqrt(s) = 7 TeV is presented. The results are based on a data set corresponding to an integrated luminosity of 5.0 inverse femtobarms, recorded by the CMS detector at the LHC in 2011. The measurement is performed in two independent channels through a trilepton analysis of t t-bar Z events and a same-sign dilepton analysis of t t-bar V (V = W or Z) events. In the trilepton channel a direct measurement of the t t-bar Z cross section sigma(t t-bar Z) = 0.28 +0.14/-0.11 (stat) +0.06/-0.03 (syst) pb is obtained. In the dilepton channel a measurement of the t t-bar V cross section yields sigma(t t-bar V) = 0.43 +0.17/-0.15 (stat) +0.09/-0.07 (syst) pb. These measurements have a significance, respectively, of 3.3 and 3.0 standard deviations from the background hypotheses and are compatible, within uncertainties, with the corresponding next-to-leading order predictions of 0.137 +0.012/-0.016 and 0.306 +0.031/-0.053 pb.

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