Next-to-leading-order QCD and electroweak corrections to triple-W production with leptonic decays at the LHC

We present a calculation of the next-to-leading-order QCD and electroweak corrections to WWW production with leptonically decaying $\mathrm{W}$ bosons at the LHC, fully taking into account off-shell contributions, intermediary resonances, and spin correlations. The contributions of the quark-antiquark-induced electroweak correction to typical fiducial cross sections at the LHC are of the order of 5-8% and grow to tens of percent in the high-energy tails of distributions. We observe strong cancellations among the positive quark-photon and negative quark-antiquark-induced electroweak corrections. In addition to results based on full $2\to 6/7$-particle next-to-leading-order matrix elements, we present a calculation based on the triple-pole approximation, which expands the matrix elements around the poles of three simultaneously resonant $\mathrm{W}$ bosons. The triple-pole approximation performs particularly well for integrated cross sections and for differential cross sections that are insensitive to off-shell effects, such as angular and rapidity distributions.