Abstract
We present a new mechanism for solving the strong problem using a discrete symmetry and an anomalous symmetry. A symmetry is used so that two gauge groups have the same theta angle. An anomalous 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 boson relaxes the QCD theta angle to the difference between the two theta angles—in this case zero. In the second model, the anomalous 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.
- Received 25 November 2014
DOI:https://doi.org/10.1103/PhysRevLett.114.141801
© 2015 American Physical Society