Interactions between vector mesons and dynamically generated resonances

Understand

The $\rho\rho$ interaction and the corresponding dynamically generated bound states are revisited.

• We demonstrate that an improved unitarization method is necessary to study the pole structures of amplitudes outside the near-threshold region.
• In this work, we extend the study of the covariant $\rho\rho$ scattering in a unitarized chiral theory to the $S$-wave interactions for the whole vector-meson nonet.
• We demonstrate that there are unphysical left-hand cuts in the on-shell factorization approach of the Bethe-Salpeter equation.