Abstract
By identifying the recently introduced Barbero-Immirzi field with the QCD axion, the strong problem can be solved through the Peccei-Quinn mechanism. A specific energy scale for the Peccei-Quinn symmetry breaking is naturally predicted by this model. This provides a complete dynamical setting to evaluate the contribution of such an axion to the cold dark matter content of the Universe. Furthermore, a tight upper bound on the tensor-to-scalar ratio production of primordial gravitational waves can be fixed, representing a strong experimental test for this model.
- Received 4 December 2009
DOI:https://doi.org/10.1103/PhysRevD.81.125015
©2010 American Physical Society