Isospin breaking exposed in f0(980)−a0(980) mixing

Isospin breaking exposed in f 0 ( 980 ) − a 0 ( 980 ) mixing

We suggest that mixing between the f0(980) and a0(980), due to their dynamical interaction with the nearby KK̄ thresholds, can give rise to a significantly enhanced production rate of a0(980) relative to a2(1320) in pp → ps(ηπ)pf as xF → 0. The peaking of the cross section as φ → 0 should also occur. We show that such effects are seen in data and deduce that the f0(980) − a0(980) mixing intensit...

Mixing of Pseudoscalar Mesons and Isospin Symmetry Breaking

Mixing of the pseudoscalar mesons is discussed in the quark-flavor basis with the hypothesis that the basis decay constants follow the pattern of particle state mixing. The divergences of the axial vector currents which embody the axial vector anomaly, combined with this hypothesis provide a calculational scheme for the parameters describing the mixing of the π, η and η mesons. Phenomenological...

Isospin Symmetry Breaking

Isospin symmetry breaking

We discuss the separation of isospin-symmetric and isospin-breaking contributions in the hadronic observables within the framework of QCD plus QED. Further, we briefly review some recent work on the low-energy hadron phenomenology, in which the isospin-breaking effect plays a prominent role.

Isospin breaking in Kl4 decays

Data on Ke4 decays allow one to extract experimental information on the elastic ππ scattering amplitude near threshold, and to confront the outcome of the analysis with predictions made in the framework of QCD. These predictions concern an isospin symmetric world, while experiments are carried out in the real world, where isospin breaking effects – generated by electromagnetic interactions and ...