New solutions on the scalar – isoscalar ππ phase shifts are analysed together with previous KK results using a separable potential model of three coupled channels (ππ , KK and an effective 2π2π system). Model parameters are fitted to two sets of solutions obtained in a recent analysis of the CERN-Cracow-Munich measurements of the πp↑ → π +π−n reaction on a polarized target. A relatively narrow ...

We show that the non-strange scalar meson, as now reported in the 1996 PDG tables, is a natural consequence of crossing symmetry as well as chiral dynamics for both strong interaction low energy scattering and alsoK ! 2 weak decays.

Low-energy scattering processes of vector meson and nucleon are an important window for studying non-perturbative QCD. The interaction with nucleon, meson-nucleon length $|\alpha_{VN}|$, is component the study hadronic interactions. Nowadays many values $|\alpha_{VN}|$ have been reported using recent photoproduction experiment data or quasi data. In addition, trace anomalous energy contribution...

One of the primary interests in investigating η meson-production reactions is that they may be suited to extract information on nucleon resonances, N, in the less-explored higher N mass region. Current knowledge of most of the nucleon resonances is mainly due to the study of πN scattering and/or pion photoproduction off the nucleon. Since the η meson is much heavier than a pion, η meson-product...

Important contributions to meson–nucleus scattering are produced by terms in the multiple-scattering series, which is defined as the sum of all diagrams where the meson scatters back and forth between a pair of static nucleons before leaving the nucleus. In particular, the sum of this series is needed for an accurate description of kaon– deuteron scattering, and appears as part of the nucleon–n...

Considering four-point correlation functions of color-singlet quark bilinears, we investigate, in the largeNc limit of QCD, the subleading diagrams that involve, in the s-channel of meson–meson scattering amplitudes, two-quark–two-antiquark intermediate states. The latter contribute, together with gluon exchanges, to the formation, at the hadronic level, of two-meson and tetraquark intermediate...