Multi-scale improved predictions for \(pp\to t\overline{t}{W }^{+}+X\)

Abstract

We compare standard fixed-order NLO QCD predictions for the full off-shell \(pp\to {e}^{+}{\nu}_{e}{\mu }^{-}{\overline{\nu }}_{\mu }{\tau }^{+}{\nu}_{\tau }b\overline{b }\left(j\right)+X\) processes in the multi-lepton decay channel with the results obtained using the MiNLO approach. The MiNLO method, now also implemented in the Helac-NLO framework, provides a dynamic determination of the renormalization and factorization scale settings by identifying the most likely branching histories of the additional jets through an inverse k_T-clustering algorithm. The inclusion of Sudakov form factors accounts for the large logarithms that arise in the presence of widely separated scales. We perform a dedicated comparison of the two approaches at both the integrated and differential (fiducial) cross-section levels for the LHC Run II energy of \(\sqrt{s}=13\) TeV. Finally, we present the merging of the full off-shell predictions for \(pp\to {e}^{+}{\nu}_{e}{\mu }^{-}{\overline{\nu }}_{\mu }{\tau }^{+}{\nu}_{\tau }b\overline{b }+X\), \(pp\to {e}^{+}{\nu}_{e}{\mu }^{-}{\overline{\nu }}_{\mu }{\tau }^{+}{\nu}_{\tau }b\overline{b }j+X\) and \(pp\to {e}^{+}{\nu}_{e}{\mu }^{-}{\overline{\nu }}_{\mu }{\tau }^{+}{\nu}_{\tau }b\overline{b }jj\), with the aim of improving the description of the underlying \(pp\to {e}^{+}{\nu}_{e}{\mu }^{-}{\overline{\nu }}_{\mu }{\tau }^{+}{\nu}_{\tau }b\overline{b }+X\) process.