Two-loop helicity amplitudes for the production of two off-shell electroweak bosons in quark-antiquark collisions.

Knowledge of two-loop QCD amplitudes for processes qq′→V1V2→(l1l¯′1)(l2l¯′2)qq′→V1V2→(l1l¯1′)(l2l¯2′) is important for improving the theoretical description of four-lepton production in hadron collisions. In this paper we compute these helicity amplitudes for all intermediate vector bosons, V 1 V 2 = γ * γ *, W + W −, ZZ, W ± Z, W ± γ *, including off-shell effects and decays to leptons