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 \V-ub/V-cb\ and the CP-violating parameter sin2beta, 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 \V-us\ approximate to rootm(u)/m(c) + m(d)/m(s) and \V-td/V-ts\ approximate to rootm(d)/m(s) obtained previously from the six-zero texture of Hermitian quark mass matrices remain unchanged in the new ansatz. (C) 2003 Elsevier Science B.V. All rights reserved.