The Full-Color Two-Loop Four-Gluon Amplitude in $\mathcal{N}=2$ Super-QCD

Abstract

We present the fully integrated form of the two-loop four-gluon amplitude in $\mathcal{N}=2$ supersymmetric quantum chromodynamics with gauge group SU$(N_c)$ and with $N_f$ massless supersymmetric quarks (hypermultiplets) in the fundamental representation. Our result maintains full dependence on $N_c$ and $N_f$, and relies on the existence of a compact integrand representation that exhibits the duality between color and kinematics. Specializing to the $\mathcal{N}=2$ superconformal theory, where $N_f=2N_c$ , we obtain remarkably simple amplitudes that have an analytic structure close to that of $\mathcal{N}=4$ super-Yang-Mills theory, except that now certain lower-weight terms appear. We comment on the corresponding results for other gauge groups.

Comments: 5 pages + refs, 1 figure, 2 ancillary files