Evidence for exclusive gamma gamma to W+W- production and constraints on anomalous quartic gauge couplings in pp collisions at sqrt(s) = 7 and 8 TeV
Evidence for exclusive gamma gamma to W+W- production and constraints on anomalous quartic gauge couplings in pp collisions at sqrt(s) = 7 and 8 TeV
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DOI：
10.1007/jhep08(2016)119
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发表时间：
2016-04
期刊：
影响因子：
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通讯作者：
Cms Collaboration
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文献类型：
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作者：
Cms Collaboration
寻找异或quasi-exclusiveγγ→W + W−生产,通过页→p (*) W + W−p(*)→(*)μ±e∓p (*) atTeV,据报道使用数据对应一个集成的光度19.7 fb−1。事件的选择要求存在具有大横向动量的电子-介子对p T (μ±e /) bbb30 GeV，并且没有从同一顶点检测到相关的带电粒子。8 TeV的结果与之前的7 TeV结果（5.05 fb−1的数据获得）相结合。在信号区，在8 (7)TeV的3.9±0.6（0.84±0.15）个事件的期望背景下观测到13(2)个事件，结果比仅背景假设的总和多3.4 σ。观测到的产率和运动分布与γγ→W+ W−的独占和准独占的标准模型预测相一致。反常四次规范耦合算子a w0， C（维数-6）和fm0, 1, 2, 3（维数-8）的上限是迄今为止最严格的，是由测量的双轻子横向动量谱推导出来的。
A search for exclusive or quasi-exclusive γγ→ W+ W− production, via pp→ p (*) W+ W− p (*)→ p (*) μ±e∓ p (*) atTeV, is reported using data corresponding to an integrated luminosity of 19.7 fb− 1. Events are selected by requiring the presence of an electron-muon pair with large transverse momentum p T (μ±e∓)> 30 GeV, and no associated charged particles detected from the same vertex. The 8 TeV results are combined with the previous 7 TeV results (obtained for 5.05 fb− 1 of data). In the signal region, 13 (2) events are observed over an expected background of 3.9±0.6 (0.84±0.15) events for 8 (7) TeV, resulting in a combined excess of 3.4 σ over the background-only hypothesis. The observed yields and kinematic distributions are compatible with the standard model prediction for exclusive and quasi-exclusive γγ→ W+ W− production. Upper limits on the anomalous quartic gauge coupling operators a W 0, C (dimension-6) and f M0, 1, 2, 3 (dimension-8), the most stringent to date, are derived from the measured dilepton transverse momentum spectrum.