Abstract
We review recent theoretical improvements of Monte Carlo event generators for top-quark pair production and decay at the LHC based on the POWHEG method. We present an event generator that implements spin correlations and off-shell effects in top-decay chains described in terms of exact matrix elements for pp→ℓ+νℓl−ν¯lbb¯ at order α4α2s, including full NLO QCD corrections and interference effects with single-top and non-resonant topologies yielding to the same final state. We then compare its predictions to previous generators that implement NLO corrections only in the top-pair production dynamics. We consider the mass distributions of the WjB and ℓjB systems, proxies for direct top-mass determinations, and jet-vetoed cross section, a probe of the Wt single top contribution.
Ježo, Tomáš