Physical properties of resonances as the building blocks of multichannel scattering amplitudes

We propose a simple formula for multichannel resonant scattering with related to physical resonant properties. It can be used to predict phase from other resonant parameters and describe the shape of amplitudes close to the resonance without any background or fitting. It works well even for overlapping resonances. unitarity to the proposed formula enabled us to explain some puzzling of much more advanced models.