Phenomenology of scalar and vector mesons in the linear σ model

A generalization of the linear σ model that includes vector and axial vector mesons is presented. The resulting effective Lagrangian incorporates some new features not previously considered. The consistency of the model is successfully checked by applying it to a variety of processes, including low-energy ππ scattering and a1 decays. An interesting feature of this new effective Lagrangian is that it provides a natural mechanism leading to a reduction of the σ→ππ decay width relative to the expected value in the original linear σ model. The generalization of the Wess-Zumino effective action appropriate to the linear σ model is also considered.