Precise tests of a quark mass texture Original Research Article

The relations |Vub/Vcb| = (mu/mc)12 and |Vtd/Vts| = (md/ms)12 between theCKM matrix elements and the quark masses are shown to imply a remarkably precise determination of the CKM unitarity triangle or of the Wolfenstein parameters ϱ, η consistent with the data so far. We view this as a clean test of a quark mass texture neatly arising from a hierarchical breaking of a U(2) flavour symmetry.