The masses of the lighter quarks

Simple observations are made about both the current masses and the constituent masses of the lighter quarks. The latest values of the decay constants fπ, fK, and fD of the pseudoscalar mesons suggest that the current-quark mass ratio 2s/(u + d) of the mass of strange quark to the average mass of the up and down quarks is closer to 14 than to 26 as is usually assumed. Such heavier masses for mu and md are also implied by a model in which the masses of the first family of fermions arise from their electric and chromoelectric fields rather than from the Higgs mechanism. Since constituent-quark masses incorporate some of the energy of the interaction, which is different for mesons and baryons, it might be useful to consider two sets of constituent-quark masses, one for mesons and one for baryons. Plausible quark mass values in MeV are u = 303, d = 307, s = 490 and c = 1668 for the meson constituents and U = 326, D = 328, S = 510 and C = 1726 for the baryon constituents. (author)