Subleading EW corrections and spin-correlation effects in $t\bar{t}W$ multi-lepton signatures

Understand

Recently a slight tension between data and predictions has been reported in $t\bar{t}W$ production by both the CMS and ATLAS collaborations.

• We revisit the theoretical predictions for this process, focussing on the following two effects.
• We disentangle various effects that lead to asymmetries among the leptonic decay products of the (anti-)top quarks and $W$ bosons, for which we find that the spin correlations in the top-quark pair are the dominant source.
• We also discuss the impact of the large, formally subleading, electroweak corrections to $t\bar{t}W$ production at the LHC.