We present a general analysis for the discovery potential of CP-violation (CPV) searches in scattering processes at TeV-scale colliders in an effective field theory framework, using the SMEFT basis for higher dimensional operators. In particular, we systematically examine the CP-violating sector of the SMEFT framework in some well motivated limiting cases, based on flavour symmetries of the underlying heavy theory. We show that, under naturality arguments of the underlying new physics (NP) and in the absence of (or suppressed) flavour-changing interactions, there is only a single operator, Qtϕ=ϕ†ϕ(q¯3t)ϕ˜ which alters the top-Yukawa coupling, that can generate a non-vanishing CP-violating effect from tree-level SM×NP interference terms. We find, however, that CPV from Qtϕ=ϕ†ϕ(q¯3t)ϕ˜ is expected to be at best of O(1%) and, therefore, very challenging if at all measurable at the LHC or other future high-energy colliders. We then conclude that a potentially measurable CP-violating effect of O(10%) can arise in high-energy scattering processes only if flavour-changing interactions are present in the underlying NP; in this case a sizable CPV can be generated at the tree-level by pure NP×NP effects and not from SM×NP interference. We provide several examples of CPV at the LHC and at a future e+e− collider to support these statements.

中文翻译：

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高能前沿 CP 违规的理论基础


我们利用高维算子的 SMEFT 基础，在 TeV 尺度对撞机的散射过程中对 CP 违规 （CPV） 搜索的发现潜力进行了一般分析。特别是，我们基于基础 heavy 理论的风味对称性，在一些动机良好的限制情况下系统地研究了 SMEFT 框架的 CP 违规部分。我们表明，在基础新物理学 （NP） 的自然性论点下，在没有（或抑制）风味改变相互作用的情况下，只有一个运算符 Qtφ=φ†φ（q ̄3t）φ ̃ 它改变了顶部汤川耦合，它可以从树级 SM×NP 干扰项中产生不消失的 CP 违背效应。然而，我们发现，Qtφ=φ†φ（q ̄3t）φ ̃ 的 CPV 预计最多为 O（1%），因此，如果在 LHC 或其他未来的高能对撞机上可以测量，则非常具有挑战性。然后我们得出结论，只有当潜在的 NP 中存在改变风味的相互作用时，O（10%） 的潜在可测量的 CP 违规效应才会在高能散射过程中出现;在这种情况下，相当大的 CPV 可以通过纯 NP×NP 效应在树级别产生，而不是由 SM×NP 干扰产生。我们提供了 LHC 和未来 e+e− 对撞机的几个 CPV 示例来支持这些说法。