Solving the strong CP problem with discrete symmetries and the right unitarity triangle

We present a solution to the strong CP problem based on spontaneous CP violation and discrete family symmetries. The model predicts in a natural way the almost right-angled quark unitarity triangle angle (alpha similar or equal to 90 degrees) by making the entries of the quark mass matrices either real or imaginary. By this choice the determinants of the mass matrices are rendered real and hence the strong CP phase vanishes. We present a toy model for the quark sector that demonstrates the viability of our approach. (C) 2013 Elsevier B.V. All rights reserved.