Diphoton Amplitudes in Three-Loop Quantum Chromodynamics

We consider the three-loop scattering amplitudes for production of a pair photons in quark-antiquark annihilation Quantum Chromodynamics (QCD). use suitably defined projectors to efficiently calculate all helicity amplitudes. obtain relatively compact analytic results, that we write terms harmonic polylogarithms or, alternatively, multiple up depth three. This is first calculation four-point amplitude full QCD.