Two-loop helicity amplitudes for W/Z boson pair production in gluon fusion with exact top mass dependence

Abstract

We compute the top quark contribution to the two-loop amplitudes for on-shell $W$/$Z$ boson pair production in gluon fusion, $gg \to WW$ and $gg \to ZZ$. Exact dependence on the top quark mass is retained, the bottom quark is considered massless. Integral reduction is performed numerically for each phase space point and the master integrals are evaluated using the auxiliary mass flow method. This allows for fast computation of the amplitudes to very high precision.