Song HeYU-TIN HUANGChia-Kai KuoZhenjie Li2023-07-212023-07-212022-11-031029-8479https://scholars.lib.ntu.edu.tw/handle/123456789/63401857 pages, version accepted in JHEPIn this paper, we present the two-loop correction to scattering amplitudes in three-dimensional $\mathcal{N}=6$ Chern-Simons matter theory. We use eight-point case as our main example, but the method generalizes to all multiplicities. The integrand is completely fixed by dual conformal symmetry, maximal cuts, constraints from soft-collinear behavior and from vanishing of odd-multiplicity amplitudes. After performing integrations with Higgs regularizations, the integrated results demonstrate that the infrared divergence is again identical to that of ${\cal N}=4$ super Yang-Mills. After subtracting divergences, the finite part is dual conformal invariant, and respects various symmetries; it has uniform transcendentality weight two and exhibits nice analytic structure.1/N Expansion | Chern-Simons Theories | Scattering Amplitudes | Supersymmetric Gauge Theory; High Energy Physics - Theory; High Energy Physics - Theoryjournal article10.1007/JHEP02(2023)0652-s2.0-85148529980http://arxiv.org/abs/2211.01792v2