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\section[\tttt production]{\tttt production}
\label{subsec:tttt}

\textbf{NOT UPDATED}

This section describes the MC samples used for the modelling of \tttt\ production.
\Cref{subsubsec:tttt_aMCP8} describes the \MGNLOPY[8] samples,
and \cref{subsubsec:tttt_aMCH7} describes the \MGNLOHER[7] samples.

\subsection[MadGraph5\_aMC@NLO+Pythia8]{\MGNLOPY[8]}
\label{subsubsec:tttt_aMCP8}

\paragraph{Samples}
%\label{par:tttt_aMCP8_samples}

The descriptions below correspond to the samples in \cref{tab:tttt_aMCP8}.

\begin{table}[htbp]
  \caption{Nominal \tttt\ samples produced with \MGNLOPY[8].}%
  \label{tab:tttt_aMCP8}
  \centering
  \begin{tabular}{l l}
    \toprule
    DSID range & Description \\
    \midrule
    412043 & \tttt \\
    \bottomrule
  \end{tabular}
\end{table}

\paragraph{Short description:}

The production of \tttt\ events was modelled using the \MGNLO[2.3.3]~\cite{Alwall:2014hca}
generator at NLO with the \NNPDF[3.1nlo]~\cite{Ball:2014uwa} parton distribution function~(PDF).
The events were interfaced with \PYTHIA[8.230]~\cite{Sjostrand:2014zea}~ using the A14 tune~\cite{ATL-PHYS-PUB-2014-021} and the
\NNPDF[2.3lo]~\cite{Ball:2014uwa} PDF set.
The decays of bottom and charm hadrons were simulated using the \EVTGEN[1.6.0] program~\cite{Lange:2001uf}.


\paragraph{Long description:}

The production of \tttt\ events was modelled using the \MGNLO[2.3.3]~\cite{Alwall:2014hca}
generator, which provided matrix elements at next-to-leading order~(NLO) in the strong coupling constant \alphas
with the \NNPDF[3.1nlo]~\cite{Ball:2014uwa} parton distribution function~(PDF).
The functional form of the renormalisation and factorisation scales was set to \(0.25\times \sum_i \sqrt{m^2_i+p^2_{\text{T},i}}\),
where the sum runs over all the particles generated from the matrix element calculation, following the Ref.~\cite{Frederix:2017wme}.
Top quarks were decayed at LO using \MADSPIN~\cite{Frixione:2007zp,Artoisenet:2012st} to preserve all spin correlations.
The events were interfaced with \PYTHIA[8.230]~\cite{Sjostrand:2014zea} for the parton shower and hadronisation,
using the A14 set of tuned parameters~\cite{ATL-PHYS-PUB-2014-021} and the \NNPDF[2.3lo]~\cite{Ball:2014uwa} PDF set.
The decays of bottom and charm hadrons were simulated using the \EVTGEN[1.6.0] program~\cite{Lange:2001uf}.


\subsection[MadGraph5\_aMC@NLO+Herwig7]{\MGNLOHER[7]}
\label{subsubsec:tttt_aMCH7}

\paragraph{Samples}
%\label{par:tttt_aMCH7_samples}

The descriptions below correspond to the samples in \cref{tab:tttt_aMCH7}.

\begin{table}[htbp]
  \caption{\tttt\ samples produced with \MGNLOHER[7].}%
  \label{tab:tttt_aMCH7}
  \centering
  \begin{tabular}{l l}
    \toprule
    DSID range & Description \\
    \midrule
    412044 & \tttt \\
    \bottomrule
  \end{tabular}
\end{table}

\paragraph{Description:}

Additional \tttt\ samples were produced with the parton shower of the nominal samples replaced by
\HERWIG[7.04]~\cite{Bahr:2008pv,Bellm:2015jjp} to evaluate the impact of using a different parton shower and hadronisation model. The H7UE set of
tuned parameters~\cite{Bellm:2015jjp} and the \MMHT[lo] PDF set~\cite{Harland-Lang:2014zoa} were used.
