Flavor symmetry breaking and mixing effects in the

Electromagnetic axial anomaly in a generalized linear sigma model

“…It is worth here to make a short comparison of our generalized linear sigma model with standard results in chiral perturbation theory. In [34], [35] and [36] a two mixing angle scheme for the decay of the pseudoscalar mesons in chiral perturbation theory was introduced which was further discussed in [37], [38] and [26]. It is interesting to note how our model fits into this scheme.…”

On theη′gluonic admixture

“…Recently, there has been considerable progress on the parametrization of the decay constants of η − η ′ system [22][23][24]. Following Reference [24], we utilize the decay constants defined by…”

“…The formalism for studying the radiative light meson decays is presented in Section 3. The recent discussions on the definition of the decay constants for η and η ′ [22][23][24] are taken into account. We then proceed to obtain the pseudoscalar mixing angle θ p and the possible gluonic content of η ′ in Section 4.…”

Properties of flavour-singlet pseudoscalar mesons from lattice QCD

“…However, they can also be used to estimate phenomenologically interesting quantities, most prominently the decay widths of η, η → γγ. To the same order in the effective theory we worked until here, one can relate the decays widths with the mixing parameters in the quark flavour basis as follows [50,51] (see Refs. [41,42] for how to include these quantities into the effective field theory framework)…”