论文标题
强 - $ cp $有和不重力
Strong-$CP$ with and without gravity
论文作者
论文摘要
从传统上讲，强烈的CP $问题被认为是一种自然难题，有时将轴突解决方案视为临时修复。重力要么被忽略，要么被视为全球peccei-quinn对称性的威胁。我们解释说，情况在根本上是不同的。在重力中，轴轴是$ s $ -matrix施加的一致性问题：每个量规部门都必须包括轴，并确切放松相应的$ \barθ$。我们表明，这有利于通过QCD的规格冗余而完全固定的轴轴的替代性和非常简单的公式，而无需全局对称性。轴轴机制是QCD $ 3 $ form的HIGGS效果，可确保物理与操作员扩展中所有订单的$ \barθ$无关。中子EDM的近乎未来的实验检测将是$ CP $竞争物理的明确信号，而不是标准模型。轴耦合与重力尺度相关。
Conventionally, the strong-$CP$ problem is assumed to be a naturalness puzzle, with the axion solution sometimes viewed as an ad hoc fix. Gravity is either ignored or taken as a threat for the global Peccei-Quinn symmetry. We explain that the situation is fundamentally different. In gravity, axion is a matter of consistency imposed by the $S$-matrix: Each gauge sector must include axion with exact relaxation of the corresponding $\barθ$. We show that this favors an alternative and remarkably simple formulation of the axion, fully fixed by the gauge redundancy of QCD, without involvement of a global symmetry. The axion mechanism is a Higgs effect for the QCD $3$-form, ensuring that physics is independent of $\barθ$ to all orders in operator expansion. A near-future experimental detection of the neutron EDM will be an unambiguous signal of $CP$-violating physics beyond the Standard Model. The axion coupling is tied to the scale of gravity.
