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\begin{document}

\title[e Reco. Validation]{Offline Electron Seeding Validation \-- Update}
\author[C. Fangmeier]{\textbf{Caleb Fangmeier} \\ Ilya Kravchenko,  Greg Snow}
\institute[UNL]{University of Nebraska \-- Lincoln}
\date{EGamma Workshop | November 21, 2017}

\titlegraphic{%
\begin{figure}
  \includegraphics[width=1in]{CMSlogo.png}\hspace{0.75in}\includegraphics[width=1in]{nebraska-n.png}
\end{figure}
}

\begin{frame}[plain]
  \titlepage%
\end{frame}

\begin{frame}{Introduction}
  \begin{itemize}
    \item Our goal is to study \textbf{seeding} for the \textbf{offline} GSF tracking with the \textbf{new pixel detector}.
    \item Specifically, we want to optimize the window sizes used in the new pixel-matching scheme already implemented in HLT.
    \item Since last update\footnote{https://indico.cern.ch/event/662743/contributions/2744847/attachments/1534642/2403597/main.pdf},
    \begin{itemize}
        \item Migrated Code from \texttt{9\_0\_2} to \texttt{9\_2\_8}
        \item Integrated the new pixel matching into the trackingNtuple. (although still a work-in-progress)
        \item Regenerated \texttt{trackingNtuple}s for dataset \\
          {\tiny \vspace{0.05in}\hspace{-0.2in}\texttt{/ZToEE\_NNPDF30\_13TeV-powheg\_M\_120\_200/
              \vspace{-0.05in}\hspace{-0.2in}RunIISummer17DRStdmix-NZSFlatPU28to62\_92X\_upgrade2017\_realistic\_v10-v1/GEN-SIM-RAW}}\vspace{0.05in}
        \item Ongoing work happening here: \url{https://github.com/cfangmeier/cmssw/tree/ValidationGsfTracks928_dev}
    \end{itemize}
  \item This Talk:
    \begin{itemize}
      \item Description of current Offline electron seeding
      \item Description of current HLT (future Offline) electron seeding
      \item Plans for 2018
    \end{itemize}
  \end{itemize}
\end{frame}

\begin{frame}{Pair Electron Seeding I}
  \begin{columns}
  \begin{column}{0.75\textwidth}
    \begin{figure}
      \includegraphics[width=\textwidth]{diagrams/Gsf_Seeding1.png}
    \end{figure}
  \end{column}
  \begin{column}{0.25\textwidth}
    \begin{figure}
      \hspace{-1in}
      \vspace{-1in}
      \includegraphics[width=1.8\textwidth]{diagrams/window1.png}
    \end{figure}
  \end{column}
  \end{columns}
  \vfill
  \footnotesize{Windows from \url{https://indico.cern.ch/event/611042/contributions/2464057/attachments/1406271/2148742/ElectronTracking30112016.pdf}}
\end{frame}

\begin{frame}{Pair Electron Seeding II}
  \begin{columns}
  \begin{column}{0.66\textwidth}
    \begin{figure}
      \includegraphics[width=\textwidth]{diagrams/Gsf_Seeding2.png}
    \end{figure}
  \end{column}
  \begin{column}{0.33\textwidth}
    \begin{figure}
      \hspace{-0.75in}
      \vspace{1in}
      \includegraphics[width=1.5\textwidth]{diagrams/window2.png}
    \end{figure}
  \end{column}
  \end{columns}
\end{frame}

\begin{frame}{Pair Electron Seeding III}
  \begin{center}
    \begin{figure}
      \includegraphics[width=\textwidth]{diagrams/Gsf_Seeding3.png}
    \end{figure}
  \end{center}
\end{frame}

\begin{frame}{Triplet Electron Seeding - Setup}
  \begin{columns}
  \begin{column}{0.45\textwidth}
    \begin{itemize}
      \item Begin with ECAL super cluster and beam spot
    \end{itemize}
  \end{column}
  \begin{column}{0.55\textwidth}
    \begin{figure}
      \includegraphics[width=\textwidth]{diagrams/seeding_base.png}
    \end{figure}
  \end{column}
  \end{columns}
\end{frame}

\begin{frame}{Triplet Electron Seeding - Introduce Seed}
  \begin{columns}
  \begin{column}{0.45\textwidth}
    \begin{itemize}
      \item Now, examine, one-by-one seeds from general tracking*
      \item Note that we do not look at all hits in an event, but rather rely on general tracking to identify seeds.
    \end{itemize}
    \vspace{0.1in}
    \hline
    \vspace{0.1in}
    {\footnotesize *initialStepSeeds, highPtTripletStepSeeds, mixedTripletStepSeeds, pixelLessStepSeeds, tripletElectronSeeds, pixelPairElectronSeeds, stripPairElectronSeeds}
  \end{column}
  \begin{column}{0.55\textwidth}
    \begin{figure}
      \includegraphics[width=\textwidth]{diagrams/seeding_step1.png}
    \end{figure}
  \end{column}
  \end{columns}
\end{frame}

\begin{frame}{Triplet Electron Seeding - Match First Hit}
  \begin{columns}
  \begin{column}{0.5\textwidth}
    \begin{itemize}
      \item Using the beam spot, the SC position, and SC energy, propagate a path through the pixels.
      \item Next, require the first hit to be within a $\delta\phi$ and $\delta z$ window. ($\delta\phi$ and $\delta R$ for FPIX)
      \item $\delta z$ window for first hit is huge as SC and beam spot positions give very little information about $z$.
    \end{itemize}
  \end{column}
  \begin{column}{0.5\textwidth}
    \begin{figure}
      \includegraphics[width=\textwidth]{diagrams/seeding_step2.png}
    \end{figure}
  \end{column}
  \end{columns}
\end{frame}

\begin{frame}{Triplet Electron Seeding - Extrapolate Vertex}
  \begin{columns}
  \begin{column}{0.45\textwidth}
    \begin{itemize}
      \item Once we have a matched hit, use it with the SC position, to find the vertex z.
      \item Vertex x and y are still the beam spot's.
      \item Just a simple linear extrapolation.
    \end{itemize}
  \end{column}
  \begin{column}{0.55\textwidth}
    \begin{figure}
      \includegraphics[width=\textwidth]{diagrams/vertex_z.png}
    \end{figure}
  \end{column}
  \end{columns}
\end{frame}

\begin{frame}{Triplet Electron Seeding - Match Other Hits}
  \begin{columns}
  \begin{column}{0.45\textwidth}
    \begin{itemize}
      \item Now forget the SC position, and propagate a new track based on the vertex and first hit positions, and the SC energy.
      \item Progress one-by-one through the remaining hits in the seed and require each one fit within a specified window around the track.
      \item Quit when all hits are matched, or a hit falls outside the window. No skipping is allowed.
      \item However, \emph{layer} skipping is not ruled out if the original seed is missing a hit in a layer
    \end{itemize}
  \end{column}
  \begin{column}{0.55\textwidth}
    \begin{figure}
      \includegraphics[width=\textwidth]{diagrams/seeding_step3.png}
    \end{figure}
  \end{column}
  \end{columns}
\end{frame}

\begin{frame}{Triplet Electron Seeding - Window Sizes}
  \begin{columns}
  \begin{column}{0.55\textwidth}
    \begin{itemize}
      \item The $\delta\phi$ and $\delta R/z$ windows for each hit are defined using three parameters.
        \begin{itemize}
          \item \texttt{highEt}
          \item \texttt{highEtThreshold}
          \item \texttt{lowEtGradient}
        \end{itemize}
      \item From these, the window size is calculated as \\
        $\texttt{highEt} + \min(0,\texttt{Et}-\texttt{highEtThreshold})*\texttt{lowEtGradient}$.
      \item For the first hit, these parameters for the $\delta \phi$ window are,
        \begin{itemize}
          \item $\texttt{highEt}=0.05$
          \item $\texttt{highEtThreshold}=20$
          \item $\texttt{lowEtGradient}=-0.002$
        \end{itemize}
      \item For the first hit, these parameters for the $\delta \phi$ window are,
    \end{itemize}
  \end{column}
  \begin{column}{0.45\textwidth}
    \begin{figure}
      \includegraphics[width=\textwidth]{figures/dphi1_max.png}
    \end{figure}
  \end{column}
  \end{columns}
  \vspace{0.1in} \hrule \vspace{0.1in}
  These parameters can be specified for each successive hit, and in bins of $\eta$, so optimization is a challenge!
\end{frame}

\begin{frame}{Triplet Electron Seeding - Handle Missing Hits}
  \begin{columns}
  \begin{column}{0.45\textwidth}
    \begin{itemize}
      \item Finally, calculate the expected number of hits based on the number of working pixel modules the track passes through.
      \item Require exact$^1$ number of matched hits depending on the expected number of hits.
        \begin{itemize}
          \item If $N_{\textrm{exp}}=4$, require $N_{\textrm{match}}=3$
          \item If $N_{\textrm{exp}}&lt;4$, require $N_{\textrm{match}}=2$
        \end{itemize}
      \item If the seed passes all requirements, all information, including
        \begin{itemize}
          \item Super cluster
          \item Original Seed
          \item Residuals (For both charge hypotheses)
        \end{itemize}
        are wrapped up and sent downstream to GSF tracking
    \end{itemize}
  \end{column}
  \begin{column}{0.55\textwidth}
    \begin{figure}
      \includegraphics[width=\textwidth]{diagrams/seeding_step4.png}
    \end{figure}
  \end{column}
  \end{columns}
  \vspace{0.1in} \hrule \vspace{0.1in}
  {\footnotesize $^1$Exact, rather than minimum to deal with duplicate seeds in input collection. Could switch to minimum with offline cross-cleaned seeds.}
\end{frame}

\begin{frame}{Outlook and Plans for 2018}
  \begin{itemize}
    \item Construct framework to measure efficiencies and fake-rates using MC-truth information.
    \item Use this framework to identify sources of inefficiency.
    \item Finally, optimize the window sizes for offline reconstruction.
  \end{itemize}
\end{frame}

\end{document}
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