Search

We present the helicity formalism for e e annihilation into two-body resonance states, and show how to systematically extract the magnitudes and relative phases of the form factors present in the one-photon exchange approximation. This entails measurement of one-particle density matrices and certain polarization correlations in the final state. We discuss, as an example, the vector meson dominance expectations for annihilation into meson resonances and show how this model can be tested. [ABSTRACT FROM AUTHOR]

Photoproduction of ρ- and ω-mesons on nucleons is considered. The possible matrix elements according to the peripheral model are constructed and the cross section is calculated, π, η, σ ( ABC) and vector meson exchange is taken into account. The angular distribution for the decay pions of polarized ρ's is discussed with particular reference to peripheral production [ABSTRACT FROM AUTHOR]

The enhancement of the K-decay compared to the K-decay is discussed on the basis of the $$|\mathop {\Delta {\rm I}}\limits^ \to | = \tfrac{1}{2}$$ -rule. The enhancement factor is calculated by dispersion methods which yield an expression depending only on the phase shift of the two pion system in the J=0, I=0,2 state. This expression has been studied in the framework of simple models for the two-pion interaction in order to obtain a survey of the possibilities for the cause of the anomalous large ratio K/ K. Only characteristic cases have been considered and, as far as possible, experimental results of the π- π-interaction are taken into account. [ABSTRACT FROM AUTHOR]