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\section{Acceptance systematics} |
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\section{Acceptance and efficiency systematics} |
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\label{sec:systematics} |
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{\bf \color{red} MANY OF THESE STUDIES NEED TO BE UPDATED WITH 38X MC} |
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This is a search for new physics contributions to |
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events with high \met and lots of jet activity. |
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As seen in Section~\ref{sec:results}, there is no |
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evidence for a contribution beyond SM expectations. |
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Strictly speaking it is impossible to talk about |
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``acceptance systematics'' because these kinds of |
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``acceptance and efficiency systematics'' because these kinds of |
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systematics only apply to a well defined final state. |
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Nevertheless, we can at least make some qualitative |
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statements. |
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Nevertheless, we can make general statements about the |
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systematic uncertainties, including quantitative |
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estimates of the systematic uncertainties associated with |
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a few specific processes. |
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The systematic uncertainty on the lepton acceptance consists |
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of two parts: the trigger efficiency uncertainty and the |
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ID and isolation of uncertainty. We discuss these in turn. |
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ID and isolation uncertainty. We discuss these in turn. |
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The trigger efficiency |
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for two leptons of $P_T>10$ GeV, with one lepton of |
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$P_T>20$ GeV is very high, except in some corners |
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of phase space, see Section~\ref{sec:trgEff}. |
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of phase space, see Section~\ref{sec:trgeffsum}. |
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We estimate the efficiency uncertainty to be a few percent, |
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mostly in the low $P_T$ region. |
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\begin{figure}[tbh] |
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\begin{center} |
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\includegraphics[width=0.75\linewidth]{eff_11.png} |
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\includegraphics[width=1.0\linewidth]{eff_35.png} |
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\includegraphics[width=1.0\linewidth]{isoEff.png} |
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\caption{\label{fig:effttbar}\protect |
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Identification and isolation efficiencies for |
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leptons from $t \to W \to \ell$ and |
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the final state. For example, in MC we find that the |
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lepton isolation efficiency differs by $\approx 4\%$ |
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{\bf per lepton} between $Z$ events and $t\bar{t}$ events\cite{ref:top}. |
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%\noindent {\bf This figure should be cut off at 100 GeV, and |
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%the y-axis should be zero-suppressed} |
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Another significant source of systematic uncertainty is |
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associated with the jet and $\met$ energy scale. The impact |
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of this uncertainty is very final-state dependent. Final |
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states characterized by lots of hadronic activity and \met are much |
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of this uncertainty is final-state dependent. Final |
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states characterized by lots of hadronic activity and \met are |
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less sensitive than final states where the \met and SumJetPt |
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are typically close to the requirement. To be more quantitative, |
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we have used the method of Reference~\cite{ref:top} to evaluate |
