Four-zero texture of Hermitian quark mass matrices and current experimental tests

We show that the four-zero texture of Hermitian quark mass matrices can survive current experimental tests: it is able to yield sufficiently large predictions for the flavor mixing parameter |Vub/Vcb| and the CP-violating parameter sin2β, without fine-tuning of the input values of quark masses, provided the (2,2),(2,3) and (3,3) elements of up and down mass matrices roughly satisfy a geometrical hierarchy. The successful relations |Vus|≈mu/mc+md/ms and |Vtd/Vts|≈md/ms obtained previously from the six-zero texture of Hermitian quark mass matrices remain unchanged in the new ansatz.