1111.3821 (Alexander C. Edison et al.)

SU(N) group-theory constraints on color-ordered five-point amplitudes at
all loop orders    [PDF]

Alexander C. Edison, Stephen G. Naculich

Color-ordered amplitudes for the scattering of n particles in the adjoint
representation of SU(N) gauge theory satisfy constraints arising solely from
group theory. We derive these constraints for n=5 at all loop orders using an
iterative approach. These constraints generalize well-known tree-level and
one-loop group theory relations.

View original: http://arxiv.org/abs/1111.3821