New flavor-kinematics dualities and extensions of nonlinear sigma models
Ian Low, Z.W. Yin
Abstract
Nonlinear sigma model (nlσm) based on the coset SU(N)×SU(N)/SU(N) exhibits several intriguing features at the leading O(p2) in the derivative expansion, such as the flavor-kinematics duality and an extended theory controlling the single and triple soft limits. In both cases the cubic biadjoint scalar theory plays a prominent role. We extend these features in two directions. First we uncover a new extended theory for SO(N+1)/SO(N) nlσm at O(p2), which is a cubic bifundamental/biadjoint scalar theory. Next we provide evidence for flavor-kinematics dualities up to O(p4) for both SU(N) and SO(N) nlσm's. In particular, we introduce a new duality building block based on the symmetric tensor δab and demonstrate several flavor-kinematics dualities for 4-point amplitudes, which precisely match the soft blocks employed to soft-bootstrap the nlσm's up to O(p4).