Comparison of $t\bar{t}W$ theory predictions in the $3\ell$ channel

TL;DR

This paper compares various theoretical predictions for the $t\bar{t}W$ process in the three-lepton decay channel, analyzing fixed-order, off-shell, and parton-shower matched approaches to assess their differences and accuracies.

Contribution

It provides a comprehensive comparison of multiple theoretical approaches, including off-shell effects and parton-shower matching, for $t\bar{t}W$ predictions in the 3-lepton channel.

Findings

Differences observed between fixed-order and parton-shower predictions.

Off-shell effects significantly impact the predicted signatures.

Parton-shower matched predictions show good agreement with fixed-order results.

Abstract

We report on our recent comparison of various theoretical approaches to predict fiducial signatures for $pp\to t\bar{t}W$ in the $3\ell$ decay channel at $\mathcal{O}(\alpha_s^3\alpha^6)$ and $\mathcal{O}(\alpha_s\alpha^8)$. The comparison includes fixed-order predictions including full off-shell effects as well as predictions based only on the double-resonant contributions by employing the Narrow-Width-Approximation. Furthermore, we include parton-shower matched predictions using the MG5 and POWHEG-BOX frameworks.