X iv : h ep - p h / 03 01 05 8 v 1 9 J an 2 00 3 Hadronic decays of η and η ′ with coupled channels 1

ar X iv : h ep - p h / 04 05 03 9 v 1 5 M ay 2 00 4 η , η ′ → π + π − γ with coupled channels

ar X iv : h ep - p h / 03 09 01 1 v 1 1 S ep 2 00 3 Two - photon decays of π 0 , η and η ′

We investigate the decays of π 0 , η and η ′ into two photons in an effective U (3) chiral Lagrangian approach without employing large N c arguments. Tree level and one-loop contributions from the anomalous Wess-Zumino-Witten Lagrangian are calculated and the importance of η-η ′ mixing and isospin violation due to different up-and down-quark masses is discussed. Unitarity corrections beyond one...

ar X iv : h ep - p h / 01 05 03 3 v 1 3 M ay 2 00 1 Threshold η and η ′ electroproduction off nucleons 1

The electroproduction of η and η ′ mesons on the proton and the neutron is investigated at tree level within the framework of U (3) chiral perturbation theory. In addition to the Born terms low-lying resonances such as the vector mesons and J P = 1/2 + , 1/2 − baryon resonances are included explicitly and their contributions are calculated. Results for the separated differential cross sections ...

ar X iv : h ep - p h / 98 06 20 9 v 1 1 J un 1 99 8 Exclusive Hadronic D Decays to η ′ and η

Hadronic decay modes D0 → (K, K)η() and (D+,D+ s ) → (π+, ρ+)η( ) are studied in the generalized factorization approach. Form factors for (D,D+ s ) → (η, η′) transitions are carefully evaluated by taking into account the wave function normalization of the η and η′. The predicted branching ratios are generally in agreement with experiment except for D0 → Kη′, D+ → π+η and D+ s → ρ+η′; the calcul...

ar X iv : h ep - p h / 05 10 20 6 v 1 1 5 O ct 2 00 5 Two mixing angle description of radiative

An analysis of various radiative V P γ decays is performed using the two mixing angle description of the η-η ′ system. The agreement is excellent. Our results are expressed both in the " octet-singlet " and in the " quark-flavour " basis. It turns out that at the present experimental accuracy, the two angles are significantly different in the former, but not in the latter basis.