Texture zeros for the Standard Model quark mass matrices

A way of counting free parameters in the quark mass matrices of the standard model, including the constraints coming from weak basis transformations, is presented; this allows one to understand the exact physical meaning of the parallel and non-parallel texture zeros which appear in some “ansätze” of the 3×3 quark mass matrices, including the CP violation phenomena in the analysis; it is shown why the six texture zeros are ruled out. Finally, a five texture zeros “ansatz” which properly copes with all experimental constrains, including the angles of the unitary triangle, is presented