Anomalous solutions to the strong CP problem.
Anomalous solutions to the strong CP problem.
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强CP问题的反常解。
DOI：
10.1103/physrevlett.114.141801
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发表时间：
2014
影响因子：
8.6
通讯作者：
A. Hook
中科院分区：
文献类型：
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作者：
A. Hook
利用Z_{2}离散对称性和反常U（1）对称性，提出了一种求解强CP问题的新机制.利用Z_{2}对称性使两个规范群具有相同的θ角。反常的U（1）对称性使得两个θ角之间的差是物理的，而和是非物理的。提出了两种模型，其中异常对称性以不同的方式体现在IR中。在第一个模型中，有无质量的双基本夸克，这一解让人想起无质量的上夸克解。在这个模型的IR中，η^π '}玻色子将QCD θ角松弛到两个θ角之间的差-在这种情况下为零。在第二个模型中，反常的U（1）对称性在IR中被实现为一个动态产生的质量项，该质量项恰好具有抵消θ角所需的相位。这两个模型都做出了非常具体的预测，即在TeV尺度上存在新的有色粒子。
We present a new mechanism for solving the strong CP problem using a Z_{2} discrete symmetry and an anomalous U(1) symmetry. A Z_{2} symmetry is used so that two gauge groups have the same theta angle. An anomalous U(1) symmetry makes the difference between the two theta angles physical and the sum unphysical. Two models are presented where the anomalous symmetry manifests itself in the IR in different ways. In the first model, there are massless bifundamental quarks, a solution reminiscent of the massless up quark solution. In the IR of this model, the η^{'} boson relaxes the QCD theta angle to the difference between the two theta angles-in this case zero. In the second model, the anomalous U(1) symmetry is realized in the IR as a dynamically generated mass term that has exactly the phase needed to cancel the theta angle. Both of these models make the extremely concrete prediction that there exist new colored particles at the TeV scale.