Recursion relations for one-loop Goldstone boson amplitudes

In this paper, we construct the recursion relations for one-loop planar integrands in $SU(N)$ nonlinear sigma model. This generalizes soft recursions tree-level amplitudes a variety of quantum field theories with special limits. The main ingredient is definition integrand, which fixed by cuts sense generalized unitarity and requiring Adler zero on all external legs. We show that does not uniquely fix so additional constraints behavior loop momentum have to be imposed. Our work first step extending modern methods effective