Light fermionic NNLO QCD corrections to top-antitop production in the quark-antiquark channel

Understand

We present the NNLO corrections to top pair production in the quark-antiquark channel proportional to the number of light quark flavors $N_l$.

• While the double real corrections were derived previously, here we compute the real-virtual and virtual-virtual contributions in this partonic channel.
• Using the antenna subtraction formalism, we show that the subtraction terms correctly approximate the real-virtual contributions in all their infrared limits.
• Combined with the integrated forms of the double real and real-virtual subtraction terms, we show analytically that the explicit infrared poles cancel at the real-virtual and virtual-virtual levels respectively, thereby demonstrating the validity of the massive extension of the NNLO antenna formalism.