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\section{Event Preselection} |
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\label{sec:eventSel} |
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{\color{red} This needs to be fixed up -- probably many mistakes present.}\\ |
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As mentioned in the introduction, the preselection is based on the |
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$t\bar{t}$ analysis. We select events with two opposite sign isolated |
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The purpose of the preselection is to define a data sample rich |
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in $t\bar{t} \to$ dileptons. We compare the kinematical |
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properties of this sample with expectations from $t\bar{t}$ |
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Monte Carlo. |
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The preselection is based on the |
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$t\bar{t}$ analysis~\cite{ref:top}. |
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We select events with two opposite sign isolated |
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leptons ($ee$, $e\mu$, or $\mu\mu$); one of the leptons must |
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have $P_T > 20$ GeV, |
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the other one must have $P_T > 10$ GeV; there must be two JPT |
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jets of $P_T > 30$ GeV and $|\eta| <$ {\color{red} xx}; the scalar sum of the |
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$P_T$ of all such jets must exceed 100 GeV; finally $\met > 50$ GeV |
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(we use tcMet). More details are given in the subsection below. |
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the other one must have $P_T > 10$ GeV. Events consistent with $Z$ are rejected. |
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In case of events with |
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more than two such leptons, we select the pair that maximizes the scalar |
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sum of lepton $P_T$'s. |
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There must be two JPT |
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jets of $P_T > 30$ GeV and $|\eta| < 2.5$; the scalar sum of the |
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$P_T$ of all such jets must exceed 100 GeV; jets must pass |
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{\tt caloJetId} and be separated by $\Delta R >$ 0.4 from any |
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lepton passing the selection. |
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Finally $\met > 50$ GeV (we use tcMet). More details are given in the subsections below. |
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\subsection{Event Cleanup} |
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\label{sec:cleanup} |
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requirements: |
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\begin{itemize} |
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\item $|\eta| < 2.5$. |
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\item $|\eta| < 2.4$. |
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\item Global Muon and Tracker Muon. |
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\item At least one of the hits from the |
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standalone muon must be used in the global fit. |
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\item Require tracker $\Delta P_T/P_T < 0.1$. This cut was not in the original top analysis. |
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It is motivated by the observation of |
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poorly measured muons in data with large |
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relative $P_T$ uncertainty, giving significant contributions to the \met. |
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%{\color{red} This is not applied to the 11 pb iteration.} |
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\end{itemize} |
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\begin{itemize} |
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\item $P_T > 10$ GeV. (The $t\bar{t}$ analysis uses 20 GeV but for |
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completeness we calculate FR down to 10 GeV). |
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% \item $P_T > 10$ GeV. (The $t\bar{t}$ analysis uses 20 GeV but for |
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% completeness we calculate FR down to 10 GeV). |
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\item $|\eta| < 2.5$. |
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where an additional GeneralTrack is found with $Dist < 0.02$ cm |
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and $\Delta \cot \theta < 0.02$ is vetoed\cite{ref:conv}. |
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\item Cleaning for ECAL spike (aka Swiss-Cross cleaning) has been applied. |
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{\color{red}Is this true?} |
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\item Cleaning for ECAL spike (aka Swiss-Cross cleaning) has been applied |
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at the reconstruction level (CMSSW 38x). |
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\end{itemize} |
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\subsection{Z veto} |
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\subsection{Invariant mass requirement} |
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\label{sec:zveto} |
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We remove $e^+e^-$ and $\mu^+ \mu^-$ events with invariant |
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mass between 76 and 105 GeV. |
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mass between 76 and 106 GeV. We also remove events |
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with invariant mass $<$ 10 GeV, since this kinematical region is |
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not well reprodced in CMS Monte Carlos. |
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In addition, we remove $Z \to \mu\mu\gamma$ |
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candidates with the $\gamma$ collinear with one of the muons. This is |
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done as follows: |
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if the ecal energy associated with one of the muons is greater than 6 GeV, |
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we add this energy to the momentum of the initial muon, and we recompute |
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the $\mu\mu$ mass. If this mass is between 76 and 106 GeV, the event is rejected. |
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\subsection{Trigger Selection} |
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\label{sec:trigSel} |
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Because most of the triggers implemented in the 2nd half of the |
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2010 run were not implemented in the Monte Carlo, no trigger |
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selection is applied on Monte Carlo data. As discussed in |
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2010 run were not implemented in the Monte Carlo, |
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we do not make any requirements on HLT bits in the Monte Carlo. |
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Instead, as discussed in |
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Section~\ref{sec:trgEff}, a trigger efficiency weight is applied |
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to each event, based on the trigger efficiencies measured on data. |
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Trigger efficiency weights are very close to 1. |
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For data, we require the logical OR of all (or most?) unprescaled |
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single and double lepton triggers that were deployed during the 2010 |
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run. These are: |
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{\color{red} Here we need to list the triggers, somehow.} |
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%For data, we require the logical OR of all (or most?) unprescaled |
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%single and double lepton triggers that were deployed during the 2010 |
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%run. These are: |
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%{\color{red} Here we need to list the triggers, somehow.} |
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For data, we use a cocktail of unprescaled single |
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and double lepton triggers. An event |
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in the $ee$ final state is required to pass at least 1 |
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single- or double-electron trigger, a |
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$\mu\mu$ event is required to pass at least 1 single |
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or double-muon trigger, while an $e\mu$ event |
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is required to pass at least 1 single-muon, single-electron, |
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or $e-\mu$ cross trigger. |
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% We currently |
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% do not require MC events to pass any triggers. |
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\begin{itemize} |
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\item single-muon triggers |
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\begin{itemize} |
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\item \verb=HLT_Mu5= |
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\item \verb=HLT_Mu7= |
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\item \verb=HLT_Mu9= |
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\item \verb=HLT_Mu11= |
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\item \verb=HLT_Mu13_v1= |
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\item \verb=HLT_Mu15_v1= |
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\item \verb=HLT_Mu17_v1= |
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\item \verb=HLT_Mu19_v1= |
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\end{itemize} |
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\item double-muon triggers |
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\begin{itemize} |
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\item \verb=HLT_DoubleMu3= |
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\item \verb=HLT_DoubleMu3_v2= |
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\item \verb=HLT_DoubleMu5_v1= |
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\end{itemize} |
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\item single-electron triggers |
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\begin{itemize} |
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\item \verb=HLT_Ele10_SW_EleId_L1R= |
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\item \verb=HLT_Ele10_LW_EleId_L1R= |
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\item \verb=HLT_Ele10_LW_L1R= |
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\item \verb=HLT_Ele10_SW_L1R= |
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\item \verb=HLT_Ele15_SW_CaloEleId_L1R= |
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\item \verb=HLT_Ele15_SW_EleId_L1R= |
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\item \verb=HLT_Ele15_SW_L1R= |
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\item \verb=HLT_Ele15_LW_L1R= |
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\item \verb=HLT_Ele17_SW_TightEleId_L1R= |
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\item \verb=HLT_Ele17_SW_TighterEleId_L1R_v1= |
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\item \verb=HLT_Ele17_SW_CaloEleId_L1R= |
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\item \verb=HLT_Ele17_SW_EleId_L1R= |
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\item \verb=HLT_Ele17_SW_LooseEleId_L1R= |
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\item \verb=HLT_Ele17_SW_TighterEleIdIsol_L1R_v2= |
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\item \verb=HLT_Ele20_SW_L1R= |
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\item \verb=HLT_Ele22_SW_TighterEleId_L1R_v2= |
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\item \verb=HLT_Ele32_SW_TightCaloEleIdTrack_L1R_v1= |
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\item \verb=HLT_Ele32_SW_TighterEleId_L1R_v2= |
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\item \verb=HLT_Ele27_SW_TightCaloEleIdTrack_L1R_v1= |
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\item \verb=HLT_Ele22_SW_TighterCaloIdIsol_L1R_v2= |
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\item \verb=HLT_Ele22_SW_TighterEleId_L1R_v3= |
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\item \verb=HLT_Ele22_SW_TighterCaloIdIsol_L1R_v2= |
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\end{itemize} |
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\item double-electron triggers |
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\begin{itemize} |
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\item \verb=HLT_DoubleEle15_SW_L1R_v1= |
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\item \verb=HLT_DoubleEle17_SW_L1R_v1= |
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\item \verb=HLT_Ele17_SW_TightCaloEleId_Ele8HE_L1R_v1= |
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\item \verb=HLT_Ele17_SW_TightCaloEleId_SC8HE_L1R_v1= |
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\item \verb=HLT_DoubleEle10_SW_L1R= |
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\item \verb=HLT_DoubleEle5_SW_L1R= |
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\end{itemize} |
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\item e-$\mu$ cross triggers |
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\begin{itemize} |
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\item \verb=HLT_Mu5_Ele5_v1= |
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\item \verb=HLT_Mu5_Ele9_v1= |
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\item \verb=HLT_Mu11_Ele8_v1= |
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\item \verb=HLT_Mu8_Ele8_v1= |
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\item \verb=HLT_Mu5_Ele13_v2= |
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\item \verb=HLT_Mu5_Ele17_v1= |
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\end{itemize} |
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\end{itemize} |
