Six-meson amplitude in QCD-like theories

We calculate the relativistic six-meson scattering amplitude at low energy within the framework of QCD-like theories with n degenerate quark flavors at next-to-leading order in the chiral counting. We discuss the cases of complex, real and pseudoreal representations, i.e. with global symmetry and breaking patterns SU(n)×SU(n)/SU(n) (extending the QCD case), SU(2n)/SO(2n), and SU(2n)/Sp(2n). In case of the one-particle-irreducible part, we obtain analytical expressions in terms of ten six-meson subamplitudes based on the flavor and group structures. We extend on our previous results obtained within the framework of the O(N+1)/O(N) nonlinear sigma model, with N being the number of meson flavors. This work allows for studying a number of properties of six-particle amplitudes at one-loop level.