guest ::
| Home > Publications database > Towards a Systematic Uncertainty Model for the $\text{Powheg}$ $bb4\ell$ Monte Carlo sample |
| Home > Publications database > Towards a Systematic Uncertainty Model for the $\text{Powheg}$ $bb4\ell$ Monte Carlo sample |
| Report | PUBDB-2025-04914 |
2025
This record in other databases: 
Please use a persistent id in citations: doi:10.3204/PUBDB-2025-04914
Report No.: ATL-PHYS-PUB-2025-036
Abstract: This note presents a study of the ATLAS Monte Carlo (MC) sample describing $pp \to b \bar{b} \ell^+ \ell^- \nu_{\ell} \bar{\nu}_{\ell}$ events at next-to-leading order in quantum chromodynamics. Events are generated using the $\text{Powheg Box Res}$ implementation of the $bb4\ell$ process and are interfaced with $\text{Pythia 8}$ for parton showering and hadronization. The nominal ATLAS $bb4\ell$ MC sample is compared to predictions from $\text{Powheg}$+$\text{Pythia 8}$ for top-quark pair production ($t\bar{t}$) and single-top production in association with a $W$-boson ($tW$). The $bb4\ell$ MC sample is intended to reduce modelling uncertainties in precision top-quark physics analyses with respect to the modelling uncertainties associated with the $t\bar{t}+tW$ MC predictions. The impact of theoretical modeling variations is evaluated and compared to the corresponding uncertainty estimate in the $t\bar{t}$ simulation. The studied uncertainties include matrix-element scale variations, changes in the $\text{Powheg}$+$\text{Pythia 8}$ matching parameters, modification of the $\text{Pythia 8}$ final-state splitting kernel via $\mu_{R}$ variations, the use of parton distribution function (PDF) sets with an alternative value of $\alpha_S(M_Z)$ and the inclusion of inverse width corrections in $bb4\ell$. These studies support the development of a systematic uncertainty model for the $bb4\ell$ simulation.
Keyword(s): TOP
; 
|
The record appears in these collections: |
PDF
PDF (PDFA)