Assessment of systematic theory uncertainties in IAM unitarization

Effective Field Theories (EFTs) for Goldstone Boson scattering at a low order allow the computation of near–threshold observables in terms few coefficients arranged by counting. As matter principle they should make sense up to an energy scale E ∼ 4πF but expansion powers momentum violates exact elastic unitarity and renders derivative unreliable much lower energies. If new–physics deviations from Standard Model are found encoded low-energy coefficients, perhaps LHC, it will be profitable extend reach EFT regimes where partial waves saturating unitarity. The methods known hadron physics as “Unitarized Chiral Perturbation Theory” its nominal or first new resonance structure (if below that reach) wave amplitude, usually have unknown uncertainties. We recapitulate our analysis systematic theory uncertainties well Inverse Amplitude Method (IAM).