Relativistic three-body model of the pi pi pi system

A three-body isobar model which satisfies Lorentz invariance and two- and three-body unitarity is used to study the continuum three-pion problem. This model has as input the pi pi amplitudes in the channels with l=0 and l=1. The authors have found that most of the low-lying resonances that decay predominantly into three pions can be explained as being due to the three-body mechanism. The model also predicts resonances with isospin 2. They have calculated the phase shifts of the pi rho system in the channel of the omega resonance.