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Revision 1.19 by vuko, Fri Jun 27 23:38:48 2008 UTC

+\section{Event reconstruction}
+\label{sec:eventReconstruction}
-<
+\subsection{Trigger selection and efficiencies}
->
+We categorize \WZ\ three-lepton final state as following
->
+\begin{itemize}
->
+\item $3e$: for \WZ events with $\W \to e \nu$ and $\Z\to \epem$.
->
+\item $2e1\mu$: for \WZ events with $\W \to \mu \nu$ and $\Z\to \epem$.
->
+\item $2\mu 1e$: for \WZ events with $\W \to e \nu$ and $\Z\to \mumu$.
->
+\item $3\mu$: for \WZ events with $\W \to \mu \nu$ and $\Z\to \mumu$.
->
+\end{itemize}
-<
+\subsection{Lepton identification}
->
+\subsection{Trigger selection and efficiencies}
-+
+Events stemming from the three-lepton final states of $\WZ$ production
-+
+are collected by the electron and/or muon triggers. For each channel,
-+
+a minimun number of HLT requirements is chosen while keeping
-+
+the HLT efficiency for selected events close to 100\%. The same
-+
+HLT requirements are used for channels with the same \Z decay mode:
-+
+\begin{itemize}
-+
+\item for $3e$ and $2e1\mu$: HLTSingleElectron or HLTDoubleElectronRelaxed
-+
+\item for $2\mu1e$ and $3\mu$: HLTSingleMuonIso
-+
+\end{itemize}
-+
+The HLT efficiencies for all modes for events passing the full
-+
+selection described in this section are given in table~\ref{tab:hlteff}.
-+
-+
+\begin{table}[tbph]
-+
+\begin{center}
-+
-+
+\begin{tabular}{llc} \hline \hline
-+
+Channel    &   HLT selection                                   & HLT efficiency \\ \hline
-+
+$3e$       &   HLTSingleElectron or HLTDoubleElectronRelaxed   &  0.996         \\
-+
+$2e1\mu$   &   HLTSingleElectron or HLTDoubleElectronRelaxed   &  0.969         \\
-+
+$2\mu 1e$  &   HLTSingleMuonIso                                &  0.966         \\
-+
+$3\mu$     &   HLTSingleMuonIso                                &  0.994         \\ \hline \hline
-+
+\end{tabular}
-+
-+
+\end{center}
-+
+\caption{HLT Efficiencies for all the events in the generated phase space that
-+
+  have been retained  by the complete event selection.}
-+
+\label{tab:hlteff}
-+
+\end{table}
-+
-+
-+
+\begin{figure}[tbp]
-+
+  \begin{center}
-+
+  \scalebox{0.7}{\includegraphics{figs/mu_isol.eps}}
-+
+  \caption{Muon isolation variables for the muon associated
-+
+    to the \W boson decay in $2e1\mu$ events: in the left plot
-+
+    we illustrate the sum of calorimetric energy in a $\Delta R=0.3$ cone
-+
+    around the muon candidate; in the right plot we display the sum of
-+
+    transverse momenta of tracks within a $\Delta R = 0.25$ cone around
-+
+    the muon candidate. The normalization of signal and background
-+
+    distributions is arbitrary.
-+
+}
-+
+  \label{fig:mu_isol}
-+
+  \end{center}
-+
+\end{figure}
-+
-+
+\begin{figure}[tb]
-+
+  \begin{center}
-+
+  \scalebox{0.6}{\includegraphics{figs/mu_SIP.eps}}
-+
+  \caption{
-+
+    Muon impact parameter significance distribution
-+
+    in $2e1\mu$ events. The normalization of signal and background
-+
+    distributions is arbitrary.
-+
+  }
-+
+  \label{fig:mu_SIP}
-+
+  \end{center}
-+
+\end{figure}
-<
+\subsection{\WZ candidate selection}
->
+\subsection{Lepton identification}
->
+\label{sec:leptonId}
-+
+The requirements used for electron identification in this analysis are described
-+
+in~\cite{noteElectronID}.
-<
+\subsection{Signal extraction}
->
+Muon candidates are selected from global muons, which are reconstructed
->
+by combining measurements in the muon chambers and the central tracker.
->
+An additional isolation criterion is imposed to require the energy
->
+measured in the calorimeters within a $\Delta R = 0.3$ cone around the
->
+muon to be smaller than 3 GeV and the sum of the $p_T$ of tracks
->
+within a $\Delta R = 0.25$ cone around the muon must be smaller than 2 GeV.
->
+These cuts reduce the background from muons originated in
->
+\b-quark decays of the $\Zbbbar$ background, which are close to tracks
->
+and clusters from the other \b-quark decay products.
->
+The signal and background distributions of these isolation variables
->
+are shown in Figure~\ref{fig:mu_isol} for the muon in $2e1\mu$ candidate
->
+events.
->
->
+%Figures~\ref{fig:muonisol} and ~\ref{fig:muonisoleffi} show the
->
+%performance of the isolation cut. The distribution of the isolation
->
+%variables for the $\Z\b\bbar(\epem\b\bbar)$ is particularly
->
+%interesting, since muons only stem from  \b-quark decays.
->
->
+The significance of the muon impact parameter in the plane
->
+transverse to the beam, $S_{IP}$, discriminates against leptons from
->
+heavy-quark decays in all standard model background processes. This
->
+variable is defined as the ratio between the measured impact parameter
->
+and its uncertainty: $S_{IP}=IP/\sigma_{IP}$, and is required to
->
+satisfy $S_{IP}<3$. This requirement is applied only for muon candidates
->
+and not for electrons. For electron candidates, a significant fraction of the
->
+background comes from misidentified light quark jets. Thus,
->
+the requirement on the impact parameter significance does not
->
+increase the significance of the $\W\to e$ channels, as can be seen in
->
+Fig.~\ref{fig:wl_IP_SvsCut}. The distribution of $S_{IP}$ for the muon
->
+in $2e1\mu$ candidate events is shown in Figure~\ref{fig:mu_SIP}.
->
->
+The muons fullfilling all these requirements will be called ``tight'', while global
->
+muons without requirements on isolation or impact parameter significance are called ``loose''.
->
->
+\begin{figure}[p]
->
+  \begin{center}
->
+  \scalebox{0.6}{\includegraphics{figs/wl_IP_eff.eps}}
->
+  \caption{Efficiency for signal and background as a function
->
+    of the requirement on the \W-boson lepton impact parameter
->
+    significance. All other criteria but the one on impact parameter
->
+    significance are applied.
->
+%    Only events with 81 GeV $< M_Z < $ 101 \gev
->
+%    are considered.
->
+  }
->
+  \label{fig:wl_IP_eff}
->
+  \end{center}
->
+%\end{figure}
->
->
+%\begin{figure}[bt]
->
+  \begin{center}
->
+  \scalebox{0.6}{\includegraphics{figs/wl_IP_SvsCut.eps}}
->
+  \caption{Signal significance as a function of requirement on
->
+    the \W-boson lepton impact parameter significance. All other criteria but
->
+    the requirement on the impact parameter significance are applied.
->
+%    Only events with 81 GeV $< M_Z < $ 101 \gev are considered.
->
+  }
->
+  \label{fig:wl_IP_SvsCut}
->
+  \end{center}
->
+\end{figure}
->
->
->
+\begin{table}[tbp]
->
+\begin{tabular}{|l|c|c|c|c|} \hline
->
+              &  $3e$ & $2e1\mu$ & $2\mu 1e$ & $3\mu$ \\ \hline \hline
->
+\multicolumn{5}{|c|}{Lepton selection} \\ \hline
->
+Electrons     &   \multicolumn{3}{|c|}{{\tt SimpleLoose} requirements for \Z reconstruction} & \\
->
+              &   \multicolumn{3}{|c|}{{\tt SimpleTight} requirements for \W} &  \\ \hline
->
+Muons         &  &  \multicolumn{3}{|c|}{ Track Isolation:$ {\tt IsoTrack}(\Delta R= 0.25) < 2 \gev$}  \\
->
+              &  &  \multicolumn{3}{|c|}{ Calorimetric Isolation:$  {\tt IsoCalo}(\Delta R = 0.3)  < 5 \gev$}  \\
->
+              &  &  \multicolumn{3}{|c|}{$S_{IP}=IP/\sigma_{IP}<3$ }  \\ \hline
->
+HLT requirement & \multicolumn{2}{|c|}{ HLTSingleElectron or HLTDoubleElectronRelaxed}
->
+                & \multicolumn{2}{|c|}{  HLTSingleMuonIso} \\ \hline
->
+\multicolumn{5}{|c|}{\Z reconstruction} \\ \hline
->
+Lepton cuts   &  \multicolumn{4}{|c|}{for both \Z leptons: $p_T > 15$ GeV} \\
->
+Mass window   &  \multicolumn{4}{|c|}{$50 \gev < M_Z < 120 \gev $ } \\
->
+Second \Z veto &  \multicolumn{4}{|c|}{No independent second \Z candidate with $50 \gev < M_Z < 120 \gev $ } \\ \hline
->
+\multicolumn{5}{|c|}{\W lepton selection} \\ \hline
->
->
+Other cuts    &     &        & $\Delta R(\mu_Z,e_W)>0.1$ &  \\ \hline
->
+Signal region  &    \multicolumn{4}{|c|}{$81 \gev < M_Z < 101 \gev $ } \\ \hline \hline
->
->
+\end{tabular}
->
+\caption{Summary of the criteria we use to select \WZ\ final state}
->
+\label{tab:allcuts}
->
+\end{table}
->
->
->
+\begin{figure}[p]
->
+  \begin{center}
->
+  \scalebox{0.6}{\includegraphics{figs/wlpt_cuteff.eps}}
->
+  \caption{Efficiency for signal and background as a function
->
+    of the cut value on the \W-boson lepton transverse momentum.
->
+    All other cuts but the cut on this variable are applied.
->
+    Only events with 81 GeV $< M_Z < $ 101 \gev
->
+    are considered.}
->
+  \label{fig:wlpt_cuteff}
->
+  \end{center}
->
+%\end{figure}
->
->
+%\begin{figure}[bt]
->
+  \begin{center}
->
+  \scalebox{0.6}{\includegraphics{figs/wlpt_cutS.eps}}
->
+  \caption{Signal significance as a function of the cut value on
->
+    the \W-boson lepton transverse momentum. All other cuts but
->
+    the cut on this variable are applied. Only events with
->
+GeV $< M_Z < $ 101 \gev are considered.}
->
+  \label{fig:wlpt_cutS}
->
+  \end{center}
->
+\end{figure}
-<
+\subsection{Systematic uncertainties}
->
+\subsection{\WZ candidate selection}
-+
+Events are accepted if they contain at least three charged leptons,
-+
+either electrons or muons, with $p_T > 15\,\mathrm{GeV}$ and $| \eta | < 2.5$ for
-+
+electrons,$| \eta | < 2.4$ for muons, as discussed in Section~\ref{sec:leptonId}.
-+
-+
+The \WZ candidate selection proceeds from building all possible
-+
+\Z-boson candidates from same-flavour opposite-charge lepton pairs.
-+
+For $\Z \to ee$ decays, electron candidates have to fulfill the loose requirements
-+
+defined in~\cite{noteElectronID}.
-+
-+
+Events are retained if the mass of the \Z boson candidate is
-+
+within 20 GeV of the \Z boson mass, $m_Z$. The event is
-+
+rejected if a second \Z candidate is found. This second \Z boson candidate is formed
-+
+using all possible same-flavour opposite-charge combinations which are left
-+
+after removing the two leptons already used for the first \Z boson candidate. This
-+
+secondary \Z boson veto helps to suppress $\Z\Z$ events.
-+
+%The invariant
-+
+%mass distribution for accepted \Z candidates is shown in
-+
+%Figure~\ref{fig:zcandidates}.
-+
-+
+% and the \Z mass resolution is shown in
-+
+%Figure~\ref{fig:dzmass}.
-+
-+
+After the \Z boson candidate is identified, the remaining leptons in the event
-+
+are required, for electrons, to pass the tight criteria described in~\cite{noteElectronID}
-+
+or, for muons, all criteria described in section~\ref{sec:leptonId}.
-+
+If more than one lepton candidate satisfies the tight requirements, the one with the
-+
+highest $p_T$ is associated with \W boson decay. This lepton's $p_T$ is effective
-+
+discriminant against \Zbbbar and \Zjets production (see Fig.~\ref{fig:wlpt_cuteff}).
-+
+We require the transverse momentum to exceed 20 GeV, as it maximizes
-+
+the significance of the \WZ\ signal with respect to background as shown in
-+
+Fig.~\ref{fig:wlpt_cutS}.
-+
-+
+An additional requirement on the isolation between electron and muon candidates is applied
-+
+for the $2\mu 1e$ channel, by demanding the value of $\Delta R$ between the electron
-+
+candidate associated with the \W boson decay and any of the two muons associated with
-+
+the \Z boson decay to be greater than 0.1.
-+
-+
+This requirement allows suppressing the contribution of $\Z \to \mu\mu$
-+
+decays, where one of the two muons radiates a photon which is reconstructed
-+
+as an electron, possibly after conversion.
-+
+% ADD THE PLOT TO JUSTIFY THIS COMMENT
-+
+% This can be seen as a peak in the dimuon
-+
+%invariant mass at  around 60 GeV in Fig.~\ref{fig:Z2mu1e_60GeVPeak}.
-+
-+
+The summary of the selection criteria is given in Table~\ref{tab:allcuts}.
-+
-+
+The expected number of the events satisfying the sequential steps of the selection
-+
+is listed in Tables~\ref{tab:sel-effA}.
-+
+In Table~\ref{tab:wz-effimatrix} we list the total selection efficiency for  different
-+
+\W and \Z boson decay modes. It can be seen lepton candidates from \W and \Z
-+
+boson decays are almost always are reconstructed with the correct flavor. As expected,
-+
+there is a small contribution from $\W \to \tau \nu_\tau \to \ell \nu_\ell \nu_\tau$
-+
+decays. However, this contribution is suppressed, mostly due to $p_T$ requirement
-+
+on the third lepton, as leptons from $\tau$ decays are not as energetic as those from
-+
+$\W \to \ell \nu$ processes.
-+
-+
+In Tables~\ref{tab:wz-matcheffi-Zee} and \ref{tab:wz-matcheffi-Zmumu} we
-+
+display the fraction of reconstructed \WZ events with correctly-matched leptons.
-+
+It can be seen that the lepton associated with the \W boson decay is correctly matched
-+
+to the true Monte Carlo lepton from the \W boson decay in more than 90\% of
-+
+the cases, even for events with several lepton candidates available to be associated
-+
+to the \W boson decay. The choice to take the lepton candidate with the leading $p_T$ is,
-+
+therefore, justified.
-+
-+
+\begin{table}[p]
-+
+  \begin{center}
-+
-+
+\begin{tabular}{lcc|cc|cc|cc|} \hline
-+
+\multicolumn{9}{c}{ {\bf $3e$ Channel}} \\ \hline  \hline
-+
+Step   & $\WZ \to 3e\nu$ &  $ \epsilon$  & $\Z+jets$ &  $ \epsilon$  & $t\bar{t}+jets$ &  $ \epsilon$  & $b\bar{b}\ell\ell$ &  $ \epsilon$\\ \hline
-+
+All events       & 185 &         & $5.82\cdot 10^6$ &    & $8.27\cdot 10^5$ &    & $1.44\cdot 10^5$ &  \\
-+
+Found $\Z \to ee$         & 73.9 & 39.9\%        & $5.02\cdot 10^5$ & 8.63\%    & $2.92\cdot 10^3$ & 0.353\%   & $2.78\cdot 10^4$ & 19.4\% \\
-+
+Second \Z veto            & 73.9 & 100\%         & $5.02\cdot 10^5$ & 100\%     & $2.92\cdot 10^3$ & 99.9\%    & $2.78\cdot 10^4$ & 100\% \\
-+
+Found $\W \to e\nu$          & 37.4 & 50.6\%        & 310 & 0.062\%       & 13.8 & 0.474\%       & 171 & 0.61\% \\
-+
+\W lepton $p_T$ cut          & 32.5 & 86.7\%        & 86.8 & 28\%  & 8.26 & 59.7\%        & 23.4 & 13.7\% \\
-+
+Passes HLT               & 32.3 & 99.6\%        & 86.8 & 100\%         & 8.26 & 100\%         & 23.3 & 99.7\% \\
-+
+\Z mass window    & 29.5 & 91.2\%        & 51.9 & 59.8\%        & 3.26 & 39.5\%        & 17.3 & 74\% \\
-+
+ \hline
-+
+  Overall efficiency  &  &  15.9\% &  &  0.00089\% &  &  0.00039\% &  &  0.012\% \\
-+
+\hline
-+
-+
+\multicolumn{9}{c}{ {\bf $2e1\mu$ Channel}} \\ \hline  \hline
-+
+Step   & $\WZ \to 2e1\mu\nu$ &  $ \epsilon$  & $\Z+jets$ &  $ \epsilon$  & $t\bar{t}+jets$ &  $ \epsilon$  & $b\bar{t}\ell\ell$ &  $ \epsilon$\\ \hline
-+
+All events       & 185 &         & $5.82\cdot 10^6$ &    & $8.27\cdot 10^5$ &    & $1.44\cdot 10^5$ &  \\
-+
+Found $\Z \to ee$         & 63.8 & 34.5\%        & $5.02\cdot 10^5$ & 8.63\%    & $2.92\cdot 10^3$ & 0.35\%   & $2.78\cdot 10^4$ & 19.4\% \\
-+
+Second \Z veto            & 63.7 & 99.9\%        & $5.02\cdot 10^5$ & 100\%     & $2.92\cdot 10^3$ & 99.9\%    & $2.78\cdot 10^4$ & 100\% \\
-+
+Found $\W \to \mu\nu$        & 42.6 & 66.8\%        & $2.19\cdot 10^3$ & 0.44\%   & 55.6 & 1.91\%        & 748 & 2.69\% \\
-+
+\W lepton $p_T$ cut          & 35.1 & 82.5\%        & 9.58 & 0.44\%       & 16.4 & 29.5\%        & 9.49 & 1.27\% \\
-+
+Passes HLT               & 34.3 & 97.6\%        & 8.32 & 86.9\%        & 14.1 & 86\%  & 9.12 & 96.1\% \\
-+
+\Z mass window    & 30.8 & 89.8\%        & 7.31 & 87.9\%        & 3.76 & 26.7\%        & 8 & 87.8\% \\
-+
+ \hline
-+
+  Overall efficiency  &  &  16.7\% &  &  0.00013\% &  &  0.00045\% &  &  0.0056\% \\
-+
+\hline
-+
-+
+\multicolumn{9}{c}{ {\bf $2\mu1e$ Channel}} \\ \hline  \hline
-+
+Step   & $\WZ \to 2\mu1e$ &  $ \epsilon$  & $\Z+jets$ &  $ \epsilon$  & $t\bar{t}+jets$ &  $ \epsilon$  & $b\bar{b}\ell\ell$ &  $ \epsilon$\\ \hline
-+
+All events       & 190 &         & $5.82\cdot 10^6$ &    & $8.27\cdot 10^5$ &    & $1.44\cdot 10^5$ &  \\
-+
+Found $\Z \to \mu\mu$     & 75.2 & 39.7\%        & $5.77\cdot 10^5$ & 9.92\%    & $2.78\cdot 10^3$ & 0.336\%   & $3.19\cdot 10^4$ & 22.2\% \\
-+
+Second \Z veto            & 75.2 & 100\%         & $5.77\cdot 10^5$ & 100\%     & $2.77\cdot 10^3$ & 99.9\%    & $3.19\cdot 10^4$ & 100\% \\
-+
+Found $\W \to e\nu$          & 44 & 58.5\%  & 702 & 0.12\%        & 15.1 & 0.54\%       & 213 & 0.67\% \\
-+
+\W lepton $p_T$ cut                  & 38.4 & 87.2\%        & 464 & 66.2\%         & 10.3 & 68\%  & 50.5 & 23.7\% \\
-+
+$\Delta R(e,\mu)$ cut    & 38.4 & 99.9\%        & 93 & 20\%    & 7.15 & 69.6\%        & 23.3 & 46\% \\
-+
+Passes HLT                       & 37.3 & 97.1\%        & 88.8 & 95.5\%        & 6.62 & 92.7\%        & 23.1 & 99.4\% \\
-+
+\Z mass window    & 33.6 & 90.1\%        & 50.3 & 56.6\%        & 2.84 & 42.9\%        & 18.8 & 81.4\% \\
-+
+ \hline
-+
+  Overall efficiency  &  &  17.7\% &  &  0.00086\% &  &  0.00034\% &  &  0.013\% \\
-+
+\hline
-+
+%\end{tabular}
-+
+%\begin{tabular}{lcc|cc|cc|cc|} \hline
-+
+\multicolumn{9}{c}{ {\bf $3\mu$ Channel}} \\ \hline  \hline
-+
+Step   & $\WZ \to 3\mu$ &  $ \epsilon$  & $\Z+jets$ &  $ \epsilon$  & $t\bar{t}+jets$ &  $ \epsilon$  & $b\bar{b}\ell\ell$ &  $ \epsilon$\\ \hline
-+
+All events       & 189 &         & $5.82\cdot 10^6$ &    & $8.27\cdot 10^5$ &    & $1.44\cdot 10^5$ &  \\
-+
+Found $\Z \to \mu\mu$     & 83.8 & 44.3\%        & $5.77\cdot 10^5$ & 9.92\%    & $2.78\cdot 10^3$ & 0.336\%   & $3.19\cdot 10^4$ & 22.2\% \\
-+
+Second \Z veto            & 83.6 & 99.8\%        & $5.77\cdot 10^5$ & 100\%     & $2.77\cdot 10^3$ & 99.9\%    & $3.19\cdot 10^4$ & 100\% \\
-+
+Found $\W \to \mu\nu$        & 51.8 & 62\%  & $2.52\cdot 10^3$ & 0.44\%   & 34.8 & 1.25\%        & 810 & 2.54\% \\
-+
+\W lepton $p_T$ cut                  & 42.5 & 81.9\%        & 1.84 & 0.07\%       & 1.16 & 3.33\%        & 8.89 & 1.1\% \\
-+
+Passes HLT                       & 42.2 & 99.4\%        & 1.84 & 100\%         & 1.16 & 100\%         & 8.89 & 100\% \\
-+
+\Z mass window    & 38.5 & 91.1\%        & 1.84 & 100\%         & 1.16 & 100\%         & 7.78 & 87.5\% \\
-+
+ \hline
-+
+Overall efficiency  &  &  20.3\% &  &  0.000032\% &  &  0.00014\% &  &  0.0054\% \\
-+
+\hline
-+
+\end{tabular}
-+
-+
+\caption{Expected number of signal and background events passing the different
-+
+  selections steps together with the efficiency of each requirement and total efficiency of
-+
+  selection criteria in the \WZ, \Zbbbar, \Zjets and \ttjets samples for an integrated luminosity
-+
+  of 1 \invfb.}
-+
+\label{tab:sel-effA}
-+
+\end{center}
-+
+\end{table}
-+
-+
+\begin{table}[p]
-+
+\begin{center}
-+
+\begin{tabular}{l|ccccc}
-+
+\hline \hline
-+
+   & \multicolumn{5}{c}{$\Z \to ee$ and \W decay modes below} \\
-+
+Reconstruction channel  &  $e \nu$
-+
+   &  $\mu \nu $
-+
+   &  $\tau \nu \to e \nu \nu  $
-+
+   &  $\tau \nu \to \mu \nu \nu $
-+
+   &  $\tau \nu \to {\rm hadrons~} \nu$
-+
+\\ \hline
-+
+$3e$       &  17.4\%  &  0.0319\%  &  6.42\%  &  0\%  &  0.162\% \\
-+
+$2e1\mu$   &  0\%  &  18.6\%  &  0\%  &  5.53\%  &  0.0485\% \\
-+
+$2\mu1e$   &  0\%  &  0\%  &  0\%  &  0\%  &  0\% \\
-+
+$3\mu$     &  0\%  &  0\%  &  0\%  &  0\%  &  0\% \\
-+
+\hline \hline
-+
-+
+ & \multicolumn{5}{c}{$\Z \to \mu\mu$ and \W decay modes below} \\
-+
+ Reconstruction channel  &  $e\nu$
-+
+   &  $\mu\nu$
-+
+   &  $\tau\nu \to e\nu\nu$
-+
+   &  $\tau\nu \to \mu\nu\nu$
-+
+   &  $\tau\nu \to {\rm hadrons~}\nu$
-+
+\\ \hline
-+
+$3e$        &  0\%  &  0\%  &  0\%  &  0\%  &  0\% \\
-+
+$2e1\mu$   &  0.0104\%  &  0\%  &  0\%  &  0\%  &  0\% \\
-+
+$2\mu1e$   &  19.6\%  &  0.0208\%  &  5.56\%  &  0\%  &  0.18\% \\
-+
+$3\mu$     &  0\%  &  23.4\%  &  0.0573\%  &  6.77\%  &  0.0164\% \\
-+
+\hline \hline
-+
+\end{tabular}
-+
+\end{center}
-+
+\caption{Selection efficiency for signal events in the four selection channels for the different
-+
+  generated \W and \Z decay channels.}
-+
+\label{tab:wz-effimatrix}
-+
-+
+%\end{table}
-+
+%\begin{table}[tbp]
-+
+\begin{center}
-+
+\begin{tabular}{llcc} \hline
-+
+  & & \multicolumn{2}{c}{Generated decay} \\
-+
+  & & \multicolumn{2}{c}{$\Z \to ee $} \\
-+
+Selection channel  &    &  $\W \to e\nu$   &  $\W \to \mu\nu$ \\
-+
+\hline \hline
-+
+\multicolumn{4}{c}{all} \\ \hline
-+
+$3e$        & all & 1644 events         & 3 events    \\
-+
+$3e$        & matched \Z & 93$\pm$1\% & 100\%\\
-+
+$3e$        & matched \W & 92$\pm$1\% & 0\\
-+
+$3e$        & matched \WZ & 91$\pm$1\% & 0\\
-+
+\hline \hline
-+
-+
+\multicolumn{4}{c}{exactly 1 \W lepton candidate} \\ \hline
-+
+$3e$        & all & 1602  events       & 0 events    \\
-+
+$3e$        & matched \Z & 94$\pm$1\% & 0\\
-+
+$3e$        & matched \W & 92$\pm$1\% & 0\\
-+
+$3e$        & matched \WZ & 91$\pm$1\% & 0\\
-+
+\hline \hline
-+
-+
+\multicolumn{4}{c}{more than 1 \W lepton candidate} \\ \hline
-+
+$3e$        & all & 42 events  & 3 events   \\
-+
+$3e$        & matched \Z & 93$\pm$4\% & 100\%\\
-+
+$3e$        & matched \W & 91 $\pm$5\% & 0\\
-+
+$3e$        & matched \WZ & 91$\pm$5\% & 0\\
-+
+\hline \hline
-+
-+
+\multicolumn{4}{c}{all} \\ \hline
-+
+$2e1\mu$   & all & 0  events   & 1746 events \\
-+
+$2e1\mu$   & matched \Z & 0 & 100\%\\
-+
+$2e1\mu$   & matched \W & 0 & 100\%\\
-+
+$2e1\mu$   & matched \WZ & 0 & 100\%\\
-+
+\hline \hline
-+
-+
+\multicolumn{4}{c}{exactly 1 \W lepton candidate} \\ \hline
-+
+$2e1\mu$   & all & 0 events    & 1715 events \\
-+
+$2e1\mu$   & matched \Z & 0 & 100\%\\
-+
+$2e1\mu$   & matched \W & 0 & 100\%\\
-+
+$2e1\mu$   & matched \WZ & 0 & 100\%\\
-+
+\hline \hline
-+
-+
+\multicolumn{4}{c}{more than 1 \W lepton candidate} \\ \hline
-+
+$2e1\mu$   & all & 0     & 31   \\
-+
+$2e1\mu$   & matched \Z & 0 & 100\%\\
-+
+$2e1\mu$   & matched \W & 0 & 100\%\\
-+
+$2e1\mu$   & matched \WZ & 0 & 100\% \\ \hline \hline
-+
+\end{tabular}
-+
+\end{center}
-+
+\caption{Fractions of events with correctly matched leptons
-+
+  to true decay product of \W and \Z decays for final states
-+
+  with generated $\Z\to ee$ decays}
-+
+\label{tab:wz-matcheffi-Zee}
-+
+\end{table}
-+
-+
-+
-+
+\begin{table}[tbp]
-+
+\begin{center}
-+
+\begin{tabular}{llcc} \hline
-+
+  & & \multicolumn{2}{c}{Generated decay:} \\
-+
+ & & \multicolumn{2}{c}{$\Z \to \mu\mu $} \\
-+
+Selection channel  &    &  $\W \to e\nu$   &  $\W \to \mu\nu$
-+
+\\
-+
+\hline \hline
-+
+\multicolumn{4}{c}{all} \\ \hline
-+
+$2\mu1e$   & all & 1895 events  & 2 events   \\
-+
+$2\mu1e$   & matched \Z & 100\% & 100\%\\
-+
+$2\mu1e$   & matched \W & 99$\pm$1\% & 0\\
-+
+$2\mu1e$   & matched \WZ & 99$\pm$1\% & 0\\
-+
+\hline \hline
-+
-+
+\multicolumn{4}{c}{exactly 1 \W lepton candidate} \\ \hline
-+
+$2\mu1e$   & all & 1847 events & 0 events    \\
-+
+$2\mu1e$   & matched \Z & 100\% & 0\\
-+
+$2\mu1e$   & matched \W & 99$\pm$1\% & 0\\
-+
+$2\mu1e$   & matched \WZ & 99$\pm$1\% & 0\\
-+
+\hline \hline
-+
-+
+\multicolumn{4}{c}{more than 1 \W lepton candidate} \\ \hline
-+
+$2\mu1e$   & all & 48 events   & 2 events    \\
-+
+$2\mu1e$   & matched \Z & 100\% & 100\%\\
-+
+$2\mu1e$   & matched \W & 94$\pm$3.5\%& 0\\
-+
+$2\mu1e$   & matched \WZ & 94$\pm$3.5\% & 0\\
-+
+\hline \hline
-+
-+
+\multicolumn{4}{c}{all} \\ \hline
-+
+$3\mu$     & all & 0 events   & 2251 events \\
-+
+$3\mu$     & matched \Z & 0 & 94$\pm$1\%\\
-+
+$3\mu$     & matched \W & 0 & 93$\pm$1\%\\
-+
+$3\mu$     & matched \WZ & 0 & 93$\pm$1\%\\
-+
+\hline \hline
-+
-+
+\multicolumn{4}{c}{exactly 1 \W lepton candidate} \\ \hline
-+
+$3\mu$     & all & 0 events    & 2207 events \\
-+
+$3\mu$     & matched \Z & 0 & 94$\pm$1\%\\
-+
+$3\mu$     & matched \W & 0 & 93$\pm$1\%\\
-+
+$3\mu$     & matched \WZ & 0 & 93$\pm$1\%\\
-+
+\hline \hline
-+
-+
+\multicolumn{4}{c}{more than 1 \W lepton candidate} \\ \hline
-+
+$3\mu$     & all & 0 events    & 44 events  \\
-+
+$3\mu$     & matched \Z & 0 & 91$\pm$4\%\\
-+
+$3\mu$     & matched \W & 0 & 91$\pm$4\%\\
-+
+$3\mu$     & matched \WZ & 0 & 91$\pm$4\%\\ \hline \hline
-+
+\end{tabular}
-+
+\end{center}
-+
+\caption{Fractions of MC \WZ events with correctly matched leptons
-+
+  to true decay product of \W and \Z decays for final states
-+
+  with generated $\Z\to \mu\mu$ decays}
-+
+\label{tab:wz-matcheffi-Zmumu}
-+
+\end{table}
-+
-+
-+
+\subsection{Complementary studies: can we use the neutrino?}
-+
-+
+In $\WZ \to  \ell^{\pm}\nu \ellell (\ell=e,\mu)$ events, the neutrino
-+
+coming from the \W-boson decay leaves the detector with a significant
-+
+amount of energy, which should reflect in a large transverse missing
-+
+energy measurement. On the other side, no large MET is expected for
-+
+the  most  important background categories, especially \Zjets,
-+
+\Zbbbar, \ZZ and \Zgamma. This expectation is confirmed, as can be
-+
+seen in Figure~\ref{fig:met}.
-+
-+
+Another variable sensitive to the presence of the neutrino
-+
+is the W transverse mass $m_T^W$, obtained by combining the missing
-+
+energy vector and the lepton associated to the \W-boson decay.
-+
+The distribution of $m_T^W$ is shown in Figure~\ref{fig:mtw}.
-+
+The signal yield could be extracted from that distribution.
-+
+This requires however additional studies and it has not been
-+
+done at this stage.
-+
-+
+%\subsection{Signal extraction}
-+
+%\input D0Matrix
-+
+\input zjetbackground
-+
-+
-+
+\section{Systematic uncertainties}
-+
+\input Sys
-+
-+
-+
+\begin{figure}[bt]
-+
+  \begin{center}
-+
+  \scalebox{0.8}{\includegraphics{figs/met_by_channel.eps}}
-+
+  \caption{Missing transverse energy for the four signal categories.
-+
+    The distributions  show the number of expected events
-+
+    for $1 fb^{-1}$. Only events with 81 GeV $< M_Z < $ 101 \gev
-+
+    are shown. All selection cuts are applied.}
-+
+  \label{fig:met}
-+
+  \end{center}
-+
+\end{figure}
-+
-+
+\begin{figure}[bt]
-+
+  \begin{center}
-+
+  \scalebox{0.8}{\includegraphics{figs/mtw_by_channel.eps}}
-+
+  \caption{\W transverse mass for the four signal categories.
-+
+    The distributions  show the number of expected events
-+
+    for $1 fb^{-1}$. Only events with 81 GeV $< M_Z < $ 101 GeV are shown.
-+
+    All selection cuts are applied.}
-+
+  \label{fig:mtw}
-+
+  \end{center}
-+
+\end{figure}

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Comparing UserCode/Vuko/Notes/WZCSA07/selection.tex (file contents): Revision 1.1 by vuko, Wed Jun 11 15:18:44 2008 UTC vs. Revision 1.19 by vuko, Fri Jun 27 23:38:48 2008 UTC

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Comparing UserCode/Vuko/Notes/WZCSA07/selection.tex (file contents):
Revision 1.1 by vuko, Wed Jun 11 15:18:44 2008 UTC vs.
Revision 1.19 by vuko, Fri Jun 27 23:38:48 2008 UTC