Mixing and decay constants of pseudoscalar mesons - art. no. 114006

We propose a new eta-eta' mixing scheme where we start from the quark flavo r basis and assume that the decay constants in that basis follow the patter n of particle state mixing. On exploiting the divergences of the axial vect or currents - which embody the axial vector anomaly - all basic parameters are fixed to first order of flavor symmetry breaking. That approach natural ly leads to a mass matrix, quadratic in the masses, with specified elements . We also test our mixing scheme against experiment and determine correctio ns to the first order values of the basic parameters from phenomenology. Fi nally, we generalize the mixing scheme to include the eta(c) Again the dive rgences of the axial vector currents fix the mass matrix and, hence, mixing angles and the charm content of the eta and eta'. [S0556-2821(98)08919-X].