Modelling uncertainties of $t\overline{t}W$ in multi-lepton channel

Abstract

We compare fixed order and parton shower matched predictions for the process $pp\to {\ell }^{+}{\nu }_{\ell }{\ell }^{-}{\bar{\nu }}_{\ell }{\ell }^{\pm }{\nu }_{\ell }b\bar{b}+X$ at NLO in QCD, including the orders $\mathcal{O}({\alpha }_s^3{\alpha }^6)$ and $\mathcal{O}({\alpha }_s{\alpha }^8)$. The comparison is performed at the integrated and differential fiducial level at the LHC with $\sqrt{s}=13$ TeV. In the absence of parton shower matching procedure that includes the full off-shell effects for this process at NLO in QCD, we propose a new prescription. It enables the inclusion of approximate full off-shell effects to currently available parton shower matched predictions at NLO in QCD.

Comments: Contribution to The Tenth Annual Conference on Large Hadron Collider Physics - LHCP 2022, 16-20 May 2022, online