Three-loop helicity amplitudes for four-quark scattering in massless QCD

We compute the three-loop corrections to helicity amplitudes for $q\bar{q}\to Q\bar{Q}$ scattering in massless QCD. In Lorentz decomposition of amplitude we avoid evanescent structures and map corresponding form factors directly physical amplitudes. reduce master integrals express them terms harmonic polylogarithms. The renormalised exhibit infrared divergences dipole quadrupole type, as predicted by previous work on structure multileg derive finite remainders present explicit results all relevant partonic channels, both equal different quark flavours.