Zhang Zhengkang
Michigan Center for Theoretical Physics (MCTP), University of Michigan, Ann Arbor, Michigan 48109, USA and Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg, Germany.
Phys Rev Lett. 2017 Jan 6;118(1):011803. doi: 10.1103/PhysRevLett.118.011803. Epub 2017 Jan 5.
W boson pair production processes at e^{+}e^{-} and pp colliders have been conventionally interpreted as measurements of WWZ and WWγ triple gauge couplings (TGCs). Such an interpretation is based on the assumption that new physics effects other than anomalous TGCs are negligible. While this "TGC dominance assumption" was well motivated and useful at LEP2 thanks to precision electroweak constraints, it is already challenged by recent LHC data. In fact, contributions from anomalous Z boson couplings that are allowed by electroweak precision data but neglected in LHC analyses, which are enhanced at high energy, can even dominate over those from the anomalous TGCs considered. This limits the generality of the anomalous TGC constraints derived in current analyses and necessitates extension of the analysis framework and a change of physics interpretation. The issue will persist as we continue to explore the high-energy frontier. We clarify and analyze the situation in the effective field theory framework, which provides a useful organizing principle for understanding standard model deviations in the high-energy regime.
在正负电子对撞机和质子-质子对撞机中，W玻色子对产生过程传统上被解释为对WWZ和WWγ三规范耦合（TGCs）的测量。这种解释基于这样一个假设，即除了反常TGCs之外的新物理效应可以忽略不计。虽然由于精确的电弱约束，这种“TGC主导假设”在LEP2实验中动机充分且有用，但它已经受到了近期大型强子对撞机（LHC）数据的挑战。事实上，电弱精确数据允许但在LHC分析中被忽略的反常Z玻色子耦合的贡献，在高能情况下会增强，甚至可能超过所考虑的反常TGCs的贡献。这限制了当前分析中得出的反常TGC约束的普遍性，因此有必要扩展分析框架并改变物理解释。随着我们继续探索高能前沿，这个问题将持续存在。我们在有效场论框架下澄清并分析了这种情况，该框架为理解高能区域的标准模型偏差提供了一个有用的组织原则。
