Speaker
Description
see Summary
Summary
I present a Monte Carlo generator that implements significant theoretical improvements in the simulation of top-quark pair production and decay at the LHC. Spin correlations and off-shell effects in top-decay chains are described in terms of exact matrix elements for $pp\to \ell^+\nu_{\ell}\, l^-\bar{\nu}_{l} \, b \,\bar b$ at NLO QCD, where $\ell$ and $l$ are two different leptonic families, and the $b$ quark is massive. Thus, the contributions from $t\bar t$ and $Wt$ single-top production as well as their quantum interference are fully included.
Matrix elements are matched to the Pythia8 parton shower using a recently proposed method that allows for a consistent treatment of resonances in the POWHEG framework.
These theoretical improvements are especially important for the interpretation of precision measurements of the top-quark mass, for single-top analyses in the $Wt$ channel, and for $t\bar t$ and $Wt$ backgrounds in the presence of jet vetoes or cuts that enhance off-shell effects. The new generator is based on a process-independent interface of the OpenLoops amplitude generator with the POWHEG-BOX framework.
