ar X iv : h ep - p h / 04 02 29 3 v 1 2 7 Fe b 20 04 η , η ′ photoproduction and electroproduction off protons

ar X iv : h ep - p h / 04 02 23 9 v 1 2 3 Fe b 20 04 The η → π 0 π 0 γγ decay in Generalized χ PT

Calculations of η → ππγγ decay in Generalized chiral perturbation theory are presented. Tree level and next-to-leading corrections are involved. Sensitivity to violation of the Standard counting is discussed.

ar X iv : h ep - p h / 02 12 25 6 v 1 1 7 D ec 2 00 2 η , η ′ photo - and electroproduction off nucleons

The photo-and electroproduction of the η, η ′ mesons on nucleons are investigated within a relativistic chiral unitary approach based on coupled channels. The s-wave potentials for electroproduction and meson-baryon scattering are derived from a chiral effective Lagrangian which includes the η ′ as an explicit degree of freedom and incorporates important features of the underlying QCD Lagrangia...

ar X iv : h ep - p h / 04 02 29 2 v 1 2 7 Fe b 20 04 1 SU ( 3 ) Chiral Effective Field

A personal overview on the present status of SU(3) chiral perturbation theory in the baryonic sector is given. Recent developments are presented and remaining challenges are pointed out.

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 / 04 05 03 9 v 1 5 M ay 2 00 4 η , η ′ → π + π − γ with coupled channels