Remark on Koide's Z3-symmetric parametrization of quark masses

The charged lepton masses may be parametrized in a Z3-symmetric language appropriate to the discussions of Koide’s formula. The phase parameter \delta_L appearing in this parametrization is experimentally indistinguishable from 2/9. We analyse Koide’s parametrization for the up (U) and down (D) quarks and argue that the data are suggestive of the low-energy values \delta_U=\delta_L/3=2/27 and \delta_D=2\delta_L/3=4/27.