Inverse amplitude method in pi pi scattering in chiral perturbation theory to two loops

The inverse amplitude method is used to unitarize the two-loop pipi scattering amplitudes of SU(2) chiral perturbation theory in the I=0,J=0,I=1,J=1, and I=2,J=0 channels. An error analysis in terms of the low energy one-loop parameters (l) over bar (1,2,3,4) and existing experimental data is undertaken. A comparison to standard resonance saturation values for the two-loop coefficients (b) over bar (1,2,3,4,5,6) is also carried out. Crossing violations are quantified and the convergence of the expansion is discussed