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# Line 1 | Line 1
1   \section{Event reconstruction}
2   \label{sec:eventReconstruction}
3  
4 < The four possible final states of \WZ
5 < production with electrons and muons in the final state are studied, $\rm e^\pm \epem$, $\mu^\pm \epem$, $\rm e^\pm \mu^+\mu^-$
6 < and $\mu^\pm \mu^+\mu^-$. They are associated to four possible classes,
7 < denoted as follows:
4 > We categorize \WZ\ three-lepton final state as following
5   \begin{itemize}
6   \item $3e$: for \WZ events with $\W \to e \nu$ and $\Z\to \epem$.
7   \item $2e1\mu$: for \WZ events with $\W \to \mu \nu$ and $\Z\to \epem$.
# Line 19 | Line 16 | Events stemming from the three-lepton fi
16   are collected by the electron and/or muon triggers. For each channel,
17   a minimun number of HLT requirements is chosen while keeping
18   the HLT efficiency for selected events close to 100\%. The same
19 < HLT requirements are used for channels with the same Z decay mode:
19 > HLT requirements are used for channels with the same \Z decay mode:
20   \begin{itemize}
21   \item for $3e$ and $2e1\mu$: HLTSingleElectron or HLTDoubleElectronRelaxed
22   \item for $2\mu1e$ and $3\mu$: HLTSingleMuonIso
# Line 27 | Line 24 | HLT requirements are used for channels w
24   The HLT efficiencies for all modes for events passing the full
25   selection described in this section are given in table~\ref{tab:hlteff}.
26  
30
27   \begin{table}[tbph]
28   \begin{center}
29  
# Line 40 | Line 36 | $3\mu$     &   HLTSingleMuonIso
36   \end{tabular}
37  
38   \end{center}
39 < \caption{HLT Efficiencies, in percent, for all
40 <  the events in the generated phase space for events retained  by
45 <  the complete event selection.}
39 > \caption{HLT Efficiencies for all the events in the generated phase space that
40 >  have been retained  by the complete event selection.}
41   \label{tab:hlteff}
42   \end{table}
43  
44 +
45 + \begin{figure}[tbp]
46 +  \begin{center}
47 +  \scalebox{0.7}{\includegraphics{figs/mu_isol.eps}}
48 +  \caption{Muon isolation variables for the muon associated
49 +    to the \W boson decay in $2e1\mu$ events: in the left plot
50 +    we illustrate the sum of calorimetric energy in a $\Delta R=0.3$ cone
51 +    around the muon candidate; in the right plot we display the sum of
52 +    transverse momenta of tracks within a $\Delta R = 0.25$ cone around
53 +    the muon candidate. The normalization of signal and background
54 +    distributions is arbitrary.
55 + }
56 +  \label{fig:mu_isol}
57 +  \end{center}
58 + \end{figure}
59 +
60 + \begin{figure}[tb]
61 +  \begin{center}
62 +  \scalebox{0.6}{\includegraphics{figs/mu_SIP.eps}}
63 +  \caption{
64 +    Muon impact parameter significance distribution
65 +    in $2e1\mu$ events. The normalization of signal and background
66 +    distributions is arbitrary.
67 +  }
68 +  \label{fig:mu_SIP}
69 +  \end{center}
70 + \end{figure}
71 +
72 +
73   \subsection{Lepton identification}
74   \label{sec:leptonId}
75  
# Line 53 | Line 77 | The requirements used for electron ident
77   in~\cite{noteElectronID}.
78  
79   Muon candidates are selected from global muons, which are reconstructed
80 < combining measurements in the muon chambers and the central tracker.
81 < An additional isolation criterion requires that the energy
80 > by combining measurements in the muon chambers and the central tracker.
81 > An additional isolation criterion is imposed to require the energy
82   measured in the calorimeters within a $\Delta R = 0.3$ cone around the
83 < muon must be smaller than 3 GeV and the sum of the $p_t$ of tracks
84 < within a $\Delta R = 0.25$ cone around the muon must be smaller than 2 \gev.
83 > muon to be smaller than 3 GeV and the sum of the $p_T$ of tracks
84 > within a $\Delta R = 0.25$ cone around the muon must be smaller than 2 GeV.
85   These cuts reduce the background from muons originated in
86   \b-quark decays of the $\Zbbbar$ background, which are close to tracks
87   and clusters from the other \b-quark decay products.
88 + The signal and background distributions of these isolation variables
89 + are shown in Figure~\ref{fig:mu_isol} for the muon in $2e1\mu$ candidate
90 + events.
91  
92   %Figures~\ref{fig:muonisol} and ~\ref{fig:muonisoleffi} show the
93   %performance of the isolation cut. The distribution of the isolation
# Line 69 | Line 96 | and clusters from the other \b-quark dec
96  
97   The significance of the muon impact parameter in the plane
98   transverse to the beam, $S_{IP}$, discriminates against leptons from
99 < heavy-quark decays in all Standard Model background processes. This
99 > heavy-quark decays in all standard model background processes. This
100   variable is defined as the ratio between the measured impact parameter
101   and its uncertainty: $S_{IP}=IP/\sigma_{IP}$, and is required to
102 < satisfy $S_{IP}<3$. This requirement is applied only for muons
103 < and not for electrons. For electrons, a significant fraction of the
104 < background comes from fake electrons and not from heavy quark decays,
105 < and a cut on the impact parameter significance shows no improvement
106 < in significance there.
102 > satisfy $S_{IP}<3$. This requirement is applied only for muon candidates
103 > and not for electrons. For electron candidates, a significant fraction of the
104 > background comes from misidentified light quark jets. Thus,
105 > the requirement on the impact parameter significance does not
106 > increase the significance of the $\W\to e$ channels, as can be seen in
107 > Fig.~\ref{fig:wl_IP_SvsCut}. The distribution of $S_{IP}$ for the muon
108 > in $2e1\mu$ candidate events is shown in Figure~\ref{fig:mu_SIP}.
109 >
110 > \begin{figure}[p]
111 >  \begin{center}
112 >  \scalebox{0.6}{\includegraphics{figs/wl_IP_eff.eps}}
113 >  \caption{Efficiency for signal and background as a function
114 >    of the requirement on the \W-boson lepton impact parameter
115 >    significance. All other criteria but the one on impact parameter
116 >    significance are applied.
117 > %    Only events with 81 GeV $< M_Z < $ 101 \gev
118 > %    are considered.
119 >  }
120 >  \label{fig:wl_IP_eff}
121 >  \end{center}
122 > %\end{figure}
123  
124 + %\begin{figure}[bt]
125 +  \begin{center}
126 +  \scalebox{0.6}{\includegraphics{figs/wl_IP_SvsCut.eps}}
127 +  \caption{Signal significance as a function of requirement on
128 +    the \W-boson lepton impact parameter significance. All other criteria but
129 +    the requirement on the impact parameter significance are applied.
130 + %    Only events with 81 GeV $< M_Z < $ 101 \gev are considered.
131 +  }
132 +  \label{fig:wl_IP_SvsCut}
133 +  \end{center}
134 + \end{figure}
135  
136  
137   \begin{table}[tbp]
138   \begin{tabular}{|l|c|c|c|c|} \hline
139                &  $3e$ & $2e1\mu$ & $2\mu 1e$ & $3\mu$ \\ \hline \hline
140   \multicolumn{5}{|c|}{Lepton selection} \\ \hline
141 < Electrons     &   \multicolumn{3}{|c|}{{\tt SimpleLoose} requirements for Z reconstruction} & \\
142 <              &   \multicolumn{3}{|c|}{{\tt SimpleTight} requirements for W} &  \\ \hline
141 > Electrons     &   \multicolumn{3}{|c|}{{\tt SimpleLoose} requirements for \Z reconstruction} & \\
142 >              &   \multicolumn{3}{|c|}{{\tt SimpleTight} requirements for \W} &  \\ \hline
143   Muons         &  &  \multicolumn{3}{|c|}{ Track Isolation:$ {\tt IsoTrack}(\Delta R= 0.25) < 2 \gev$}  \\
144                &  &  \multicolumn{3}{|c|}{ Calorimetric Isolation:$  {\tt IsoCalo}(\Delta R = 0.3)  < 5 \gev$}  \\
145                &  &  \multicolumn{3}{|c|}{$S_{IP}=IP/\sigma_{IP}<3$ }  \\ \hline
146   HLT requirement & \multicolumn{2}{|c|}{ HLTSingleElectron or HLTDoubleElectronRelaxed}
147                  & \multicolumn{2}{|c|}{  HLTSingleMuonIso} \\ \hline
148 < \multicolumn{5}{|c|}{Z reconstruction} \\ \hline
149 < Lepton cuts   &  \multicolumn{4}{|c|}{for both Z leptons: $p_t > 15 GeV$} \\
148 > \multicolumn{5}{|c|}{\Z reconstruction} \\ \hline
149 > Lepton cuts   &  \multicolumn{4}{|c|}{for both \Z leptons: $p_T > 15$ GeV} \\
150   Mass window   &  \multicolumn{4}{|c|}{$50 \gev < M_Z < 120 \gev $ } \\
151 < Second Z veto &  \multicolumn{4}{|c|}{No independent second Z candidate with $50 \gev < M_Z < 120 \gev $ } \\ \hline
152 < \multicolumn{5}{|c|}{W lepton selection} \\ \hline
151 > Second \Z veto &  \multicolumn{4}{|c|}{No independent second \Z candidate with $50 \gev < M_Z < 120 \gev $ } \\ \hline
152 > \multicolumn{5}{|c|}{\W lepton selection} \\ \hline
153  
154   Other cuts    &     &        & $\Delta R(\mu_Z,e_W)>0.1$ &  \\ \hline
155   Signal region  &    \multicolumn{4}{|c|}{$81 \gev < M_Z < 101 \gev $ } \\ \hline \hline
156  
157   \end{tabular}
158 < \caption{Summary of all cuts used in the WZ selection}
158 > \caption{Summary of the criteria we use to select \WZ\ final state}
159   \label{tab:allcuts}
160   \end{table}
161  
# Line 112 | Line 166 | Signal region  &    \multicolumn{4}{|c|}
166    \caption{Efficiency for signal and background as a function
167      of the cut value on the \W-boson lepton transverse momentum.
168      All other cuts but the cut on this variable are applied.
169 <    Only events with 81.1 GeV $< M_Z < $ 101.1 \gev
169 >    Only events with 81 GeV $< M_Z < $ 101 \gev
170      are considered.}
171    \label{fig:wlpt_cuteff}
172    \end{center}
# Line 124 | Line 178 | Signal region  &    \multicolumn{4}{|c|}
178    \caption{Signal significance as a function of the cut value on
179      the \W-boson lepton transverse momentum. All other cuts but
180      the cut on this variable are applied. Only events with
181 <    81.1 GeV $< M_Z < $ 101.1 \gev are considered.}
181 >    81 GeV $< M_Z < $ 101 \gev are considered.}
182    \label{fig:wlpt_cutS}
183    \end{center}
184   \end{figure}
# Line 133 | Line 187 | Signal region  &    \multicolumn{4}{|c|}
187   \subsection{\WZ candidate selection}
188  
189   Events are accepted if they contain at least three charged leptons,
190 < either electrons or muons, with $p_t > 15\,\mathrm{GeV}$ and $| \eta | < 2.5$ for
191 < electrons,$| \eta | < 2.4$ for muons.
138 < as discussed in~\ref{sec:leptonId}.
190 > either electrons or muons, with $p_T > 15\,\mathrm{GeV}$ and $| \eta | < 2.5$ for
191 > electrons,$| \eta | < 2.4$ for muons, as discussed in Section~\ref{sec:leptonId}.
192  
193   The \WZ candidate selection proceeds from building all possible
194   \Z-boson candidates from same-flavour opposite-charge lepton pairs.
195 < For $\Z \to ee$ decays, electrons have to fullfil the loose requirements
195 > For $\Z \to ee$ decays, electron candidates have to fulfill the loose requirements
196   defined in~\cite{noteElectronID}.
197  
198 < Events are retained if the mass of this \Z-boson candidate is
199 < within 20 GeV of the Z-boson mass,$m_Z$. The event is
200 < rejected if a second Z candidate is found. This second Z candidate is done
201 < with all possible same-flavour opposite-charge combinations which are left
202 < after removing the two leptons already used for the first Z candidate. This
203 < veto on the presence of a second Z helps to suppress $ZZ$ events. The invariant
204 < mass distribution for accepted \Z candidates is shown in
205 < Figure~\ref{fig:zcandidates}.
198 > Events are retained if the mass of the \Z boson candidate is
199 > within 20 GeV of the \Z boson mass, $m_Z$. The event is
200 > rejected if a second \Z candidate is found. This second \Z boson candidate is formed
201 > using all possible same-flavour opposite-charge combinations which are left
202 > after removing the two leptons already used for the first \Z boson candidate. This
203 > secondary \Z boson veto helps to suppress $\Z\Z$ events.
204 > %The invariant
205 > %mass distribution for accepted \Z candidates is shown in
206 > %Figure~\ref{fig:zcandidates}.
207  
208   % and the \Z mass resolution is shown in
209   %Figure~\ref{fig:dzmass}.
210  
211 < After the \Z-boson candidate is identified, the lepton associated
212 < to the  \W-boson decay is chosen from the remaining electrons and muons
213 < in the event that have not been used for reconstructing the \Z-boson.
214 < Electrons are required to pass the tight criteria described in
215 < \cite{noteElectronID}.  If the event contains more than three leptons,
216 < the highest $p_t$ is chosen as the one from the \W-boson decay, and
217 < the additional leptons are not considered further.
218 < The transverse momentum of this lepton is required to be larger
219 < than 20 GeV. This last requirement is effective in rejecting
220 < the \Zbbbar and \Zjets backgrounds, see Figure~\ref{fig:wlpt_cuteff},
221 < and the cut value is chosen in
222 < the range that maximises the significance as shown in
223 < Figure~\ref{fig:wlpt_cutS}.
224 <
225 < An additional requirement on the isolation between electron and muons is applied
226 < for the $2\mu 1e$ channel, by demanding $\Delta R$ between the electron associated
173 < to the \W-decay and any of the two muons associated to the \Z-decay be greater than
174 < 0.1. This requirement allows to suppress the contributions of $\Z \to \mu\mu$
211 > After the \Z boson candidate is identified, the remaining leptons in the event
212 > are required, for electrons, to pass the tight criteria described in~\cite{noteElectronID}
213 > or, for muons, all criteria described in section~\ref{sec:leptonId}.
214 > If more than one lepton candidate satisfies the tight requirements, the one with the
215 > highest $p_T$ is associated with \W boson decay. This lepton's $p_T$ is effective
216 > discriminant against \Zbbbar and \Zjets production (see Fig.~\ref{fig:wlpt_cuteff}).
217 > We require the transverse momentum to exceed 20 GeV, as it maximizes
218 > the significance of the \WZ\ signal with respect to background as shown in
219 > Fig.~\ref{fig:wlpt_cutS}.
220 >
221 > An additional requirement on the isolation between electron and muon candidates is applied
222 > for the $2\mu 1e$ channel, by demanding the value of $\Delta R$ between the electron
223 > candidate associated with the \W boson decay and any of the two muons associated with
224 > the \Z boson decay to be greater than 0.1.
225 >
226 > This requirement allows suppressing the contribution of $\Z \to \mu\mu$
227   decays, where one of the two muons radiates a photon which is reconstructed
228 < as electrons, possibly after conversion, which shows up as a peak at  around 60 GeV
229 < in the Z mass distribution, as shown in figure~\ref{fig:Z2mu1e_60GeVPeak}.
228 > as an electron, possibly after conversion. This can be seen as a peak in the dimuon
229 > invariant mass at  around 60 GeV in Fig.~\ref{fig:Z2mu1e_60GeVPeak}.
230  
231 < The summary of the selection can be seen in Table~\ref{tab:allcuts}.
231 > The summary of the selection criteria is given in Table~\ref{tab:allcuts}.
232  
233 < The expected number of events passing the various steps of the selection
234 < is listed in Tables~\ref{tab:sel-effA} and~\ref{tab:sel-effB}.
235 < Table~\ref{tab:wz-effimatrix} lists the final selection efficiency for
236 < the different generated \W and \Z decays. It can be seen there that \WZ\
237 < events with both the \W and the \Z boson decaying into electrons or muons
238 < almost always get reconstructed with the correct flavour. It is to be
239 < noted in addition that each of our four selection channels gets a small
240 < contribution from $W \to \tau \to e/\mu$ decays as one would expect. The
241 < selection efficiency for these events is however smaller which is mostly due
242 < to the \pt cut on the third lepton, since the \pt spectrum of electrons or
243 < muons from $W \to \tau \to e/\mu$ decays is softer.
233 > The expected number of the events satisfying the sequential steps of the selection
234 > is listed in Tables~\ref{tab:sel-effA}.  
235 > In Table~\ref{tab:wz-effimatrix} we list the total selection efficiency for  different
236 > \W and \Z boson decay modes. It can be seen lepton candidates from \W and \Z
237 > boson decays are almost always are reconstructed with the correct flavor. As expected,
238 > there is a small contribution from $\W \to \tau \nu_\tau \to \ell \nu_\ell \nu_\tau$
239 > decays. However, this contribution is suppressed, mostly due to $p_T$ requirement
240 > on the third lepton, as leptons from $\tau$ decays are not as energetic as those from
241 > $\W \to \ell \nu$ processes.
242 >
243 > In Tables~\ref{tab:wz-matcheffi-Zee} and \ref{tab:wz-matcheffi-Zmumu} we
244 > display the fraction of reconstructed \WZ events with correctly-matched leptons.
245 > It can be seen that the lepton associated with the \W boson decay is correctly matched
246 > to the true Monte Carlo lepton from the \W boson decay in more than 90\% of
247 > the cases, even for events with several lepton candidates available to be associated
248 > to the \W boson decay. The choice to take the lepton candidate with the leading $p_T$ is,
249 > therefore, justified.
250  
251   \begin{table}[p]
252    \begin{center}
253  
254 <
255 <
256 <
257 < \begin{tabular}{lcccc} \hline
258 < \multicolumn{5}{c}{ {\bf $3e$ Channel}} \\ \hline  \hline
259 < Step   & WZ  & bbll  & Z+jets  & TTbar+jets\\ \hline
260 < All events       & 546   & 72770.4       & 1.2679e+06    & 17556.1 \\
261 < Found $Z \to ee$         & 204.969 (37.5401 \%)  & 27800.5 (38.203 \%)   & 502344 (39.62 \%)     & 2920.59 (16.6357 \%) \\
262 < Found $W \to e$          & 41.9925 (20.4872 \%)  & 171.053 (0.615286 \%)         & 309.563 (0.0616238 \%)        & 13.8293 (0.473511 \%) \\
263 < W Lepton Pt cut          & 34.8561 (83.0056 \%)  & 23.7161 (13.8648 \%)  & 86.7924 (28.037 \%)   & 8.25515 (59.6931 \%) \\
264 < Passes HLT               & 34.7185 (99.6052 \%)  & 23.5679 (99.375 \%)   & 86.7924 (100 \%)      & 8.25515 (100 \%) \\
265 < Z mass window    & 31.5533 (90.8834 \%)  & 17.4906 (74.2138 \%)  & 51.8927 (59.7894 \%)  & 3.2585 (39.4724 \%) \\ \hline
208 < Overall efficiency  & 5.77899 \% & 0.0240354 \% & 0.00409279 \% & 0.0185605 \% \\
254 > \begin{tabular}{lcc|cc|cc|cc|} \hline
255 > \multicolumn{9}{c}{ {\bf $3e$ Channel}} \\ \hline  \hline
256 > Step   & $\WZ \to 3e\nu$ &  $ \epsilon$  & $\Z+jets$ &  $ \epsilon$  & $t\bar{t}+jets$ &  $ \epsilon$  & $b\bar{b}\ell\ell$ &  $ \epsilon$\\ \hline
257 > All events       & 185 &         & $5.82\cdot 10^6$ &    & $8.27\cdot 10^5$ &    & $1.44\cdot 10^5$ &  \\
258 > 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\% \\
259 > 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\% \\
260 > Found $\W \to e\nu$          & 37.4 & 50.6\%        & 310 & 0.062\%       & 13.8 & 0.474\%       & 171 & 0.61\% \\
261 > \W lepton $p_T$ cut          & 32.5 & 86.7\%        & 86.8 & 28\%  & 8.26 & 59.7\%        & 23.4 & 13.7\% \\
262 > Passes HLT               & 32.3 & 99.6\%        & 86.8 & 100\%         & 8.26 & 100\%         & 23.3 & 99.7\% \\
263 > \Z mass window    & 29.5 & 91.2\%        & 51.9 & 59.8\%        & 3.26 & 39.5\%        & 17.3 & 74\% \\
264 > \hline
265 >  Overall efficiency  &  &  15.9\% &  &  0.00089\% &  &  0.00039\% &  &  0.012\% \\
266   \hline
210 \end{tabular}
211 \begin{tabular}{lcccc} \hline
212 \multicolumn{5}{c}{ {\bf $2e1\mu$ Channel}} \\ \hline  \hline
213 Step   & WZ  & bbll  & Z+jets  & \ttjets\\ \hline
214 All events       & 546   & 72770.4       & 1.2679e+06    & 17556.1 \\
215 Found $Z \to ee$         & 204.969 (37.5401 \%)  & 27800.5 (38.203 \%)   & 502344 (39.62 \%)     & 2920.59 (16.6357 \%) \\
216 Found $W \to \mu$        & 47.9099 (23.3743 \%)  & 747.725 (2.68961 \%)  & 2194.09 (0.436771 \%)         & 56.7645 (1.9436 \%) \\
217 W Lepton Pt cut          & 37.0973 (77.4313 \%)  & 9.63467 (1.28853 \%)  & 9.57604 (0.436446 \%)         & 17.5382 (30.8965 \%) \\
218 Passes HLT               & 36.1929 (97.5623 \%)  & 9.26411 (96.1538 \%)  & 8.32189 (86.9033 \%)  & 15.2488 (86.9457 \%) \\
219 Z mass window    & 32.5166 (89.8425 \%)  & 8.15242 (88 \%)       & 7.31467 (87.8968 \%)  & 4.91533 (32.2343 \%) \\ \hline
220 Overall efficiency  & 5.95542 \% & 0.0112029 \% & 0.000576911 \% & 0.0279978 \% \\
221 \hline
222 \end{tabular}
267  
268 < \begin{tabular}{lcccc} \hline
269 < \multicolumn{5}{c}{ {\bf $2\mu1e$ Channel}} \\ \hline  \hline
270 < Step   & WZ  & bbll  & Z+jets  & TTbar+jets\\ \hline
271 < All events       & 546   & 72770.4       & 1.2679e+06    & 17556.1 \\
272 < Found $Z \to \mu\mu$     & 233.75 (42.8114 \%)   & 31889.4 (43.8219 \%)  & 577257 (45.5284 \%)   & 2778.81 (15.8282 \%) \\
273 < Found $W \to e$          & 48.7553 (20.8579 \%)  & 213.519 (0.669562 \%)         & 701.695 (0.121557 \%)         & 15.1085 (0.543704 \%) \\
274 < W Lepton Pt cut                  & 40.6556 (83.3871 \%)  & 50.6191 (23.707 \%)   & 464.493 (66.196 \%)   & 10.2745 (68.0047 \%) \\
275 < $\Delta R(e,\mu)$ cut    & 40.5573 (99.7582 \%)  & 23.3456 (46.1201 \%)  & 92.9813 (20.0178 \%)  & 7.14967 (69.5865 \%) \\
276 < Passes HLT                       & 39.4171 (97.1886 \%)  & 23.1973 (99.3651 \%)  & 88.7791 (95.4806 \%)  & 6.6245 (92.6546 \%) \\
277 < Z mass window    & 35.5638 (90.2244 \%)  & 18.8988 (81.4696 \%)  & 50.2509 (56.6022 \%)  & 2.84083 (42.8837 \%) \\ \hline
278 < Overall efficiency  & 6.51352 \% & 0.0259704 \% & 0.00396331 \% & 0.0161814 \% \\
268 > \multicolumn{9}{c}{ {\bf $2e1\mu$ Channel}} \\ \hline  \hline
269 > Step   & $\WZ \to 2e1\mu\nu$ &  $ \epsilon$  & $\Z+jets$ &  $ \epsilon$  & $t\bar{t}+jets$ &  $ \epsilon$  & $b\bar{t}\ell\ell$ &  $ \epsilon$\\ \hline
270 > All events       & 185 &         & $5.82\cdot 10^6$ &    & $8.27\cdot 10^5$ &    & $1.44\cdot 10^5$ &  \\
271 > 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\% \\
272 > 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\% \\
273 > Found $\W \to \mu\nu$        & 42.6 & 66.8\%        & $2.19\cdot 10^3$ & 0.44\%   & 55.6 & 1.91\%        & 748 & 2.69\% \\
274 > \W lepton $p_T$ cut          & 35.1 & 82.5\%        & 9.58 & 0.44\%       & 16.4 & 29.5\%        & 9.49 & 1.27\% \\
275 > Passes HLT               & 34.3 & 97.6\%        & 8.32 & 86.9\%        & 14.1 & 86\%  & 9.12 & 96.1\% \\
276 > \Z mass window    & 30.8 & 89.8\%        & 7.31 & 87.9\%        & 3.76 & 26.7\%        & 8 & 87.8\% \\
277 > \hline
278 >  Overall efficiency  &  &  16.7\% &  &  0.00013\% &  &  0.00045\% &  &  0.0056\% \\
279   \hline
236 \end{tabular}
280  
281 <
282 < \begin{tabular}{lcccc} \hline
283 < \multicolumn{5}{c}{ {\bf $3\mu$ Channel}} \\ \hline  \hline
284 < Step   & WZ  & bbll  & Z+jets  & TTbar+jets\\ \hline
285 < All events       & 546   & 72770.4       & 1.2679e+06    & 17556.1 \\
286 < Found $Z \to \mu\mu$     & 233.75 (42.8114 \%)   & 31889.4 (43.8219 \%)  & 577257 (45.5284 \%)   & 2778.81 (15.8282 \%) \\
287 < Found $W \to \mu$        & 57.7986 (24.7267 \%)  & 810.721 (2.54229 \%)  & 2520.69 (0.436668 \%)         & 35.3061 (1.27054 \%) \\
288 < W Lepton Pt cut                  & 44.2533 (76.5646 \%)  & 8.89355 (1.09699 \%)  & 1.84115 (0.0730414 \%)        & 1.683 (4.76688 \%) \\
289 < Passes HLT                       & 43.9977 (99.4225 \%)  & 8.89355 (100 \%)      & 1.84115 (100 \%)      & 1.683 (100 \%) \\
290 < Z mass window    & 40.0462 (91.0188 \%)  & 7.78185 (87.5 \%)     & 1.84115 (100 \%)      & 1.15783 (68.7957 \%) \\ \hline
291 < Overall efficiency  & 7.33446 \% & 0.0106937 \% & 0.000145212 \% & 0.00659501 \% \\
281 > \multicolumn{9}{c}{ {\bf $2\mu1e$ Channel}} \\ \hline  \hline
282 > Step   & $\WZ \to 2\mu1e$ &  $ \epsilon$  & $\Z+jets$ &  $ \epsilon$  & $t\bar{t}+jets$ &  $ \epsilon$  & $b\bar{b}\ell\ell$ &  $ \epsilon$\\ \hline
283 > All events       & 190 &         & $5.82\cdot 10^6$ &    & $8.27\cdot 10^5$ &    & $1.44\cdot 10^5$ &  \\
284 > 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\% \\
285 > 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\% \\
286 > Found $\W \to e\nu$          & 44 & 58.5\%  & 702 & 0.12\%        & 15.1 & 0.54\%       & 213 & 0.67\% \\
287 > \W lepton $p_T$ cut                  & 38.4 & 87.2\%        & 464 & 66.2\%         & 10.3 & 68\%  & 50.5 & 23.7\% \\
288 > $\Delta R(e,\mu)$ cut    & 38.4 & 99.9\%        & 93 & 20\%    & 7.15 & 69.6\%        & 23.3 & 46\% \\
289 > Passes HLT                       & 37.3 & 97.1\%        & 88.8 & 95.5\%        & 6.62 & 92.7\%        & 23.1 & 99.4\% \\
290 > \Z mass window    & 33.6 & 90.1\%        & 50.3 & 56.6\%        & 2.84 & 42.9\%        & 18.8 & 81.4\% \\
291 > \hline
292 >  Overall efficiency  &  &  17.7\% &  &  0.00086\% &  &  0.00034\% &  &  0.013\% \\
293 > \hline
294 > %\end{tabular}
295 > %\begin{tabular}{lcc|cc|cc|cc|} \hline
296 > \multicolumn{9}{c}{ {\bf $3\mu$ Channel}} \\ \hline  \hline
297 > Step   & $\WZ \to 3\mu$ &  $ \epsilon$  & $\Z+jets$ &  $ \epsilon$  & $t\bar{t}+jets$ &  $ \epsilon$  & $b\bar{b}\ell\ell$ &  $ \epsilon$\\ \hline
298 > All events       & 189 &         & $5.82\cdot 10^6$ &    & $8.27\cdot 10^5$ &    & $1.44\cdot 10^5$ &  \\
299 > 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\% \\
300 > 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\% \\
301 > Found $\W \to \mu\nu$        & 51.8 & 62\%  & $2.52\cdot 10^3$ & 0.44\%   & 34.8 & 1.25\%        & 810 & 2.54\% \\
302 > \W lepton $p_T$ cut                  & 42.5 & 81.9\%        & 1.84 & 0.07\%       & 1.16 & 3.33\%        & 8.89 & 1.1\% \\
303 > Passes HLT                       & 42.2 & 99.4\%        & 1.84 & 100\%         & 1.16 & 100\%         & 8.89 & 100\% \\
304 > \Z mass window    & 38.5 & 91.1\%        & 1.84 & 100\%         & 1.16 & 100\%         & 7.78 & 87.5\% \\
305 > \hline
306 > Overall efficiency  &  &  20.3\% &  &  0.000032\% &  &  0.00014\% &  &  0.0054\% \\
307   \hline
308   \end{tabular}
309  
252
310   \caption{Expected number of signal and background events passing the different
311 <  selections steps in the \WZ, \Zbbbar, \Zjets and \ttjets samples for an integrated luminosity
311 >  selections steps together with the efficiency of each requirement and total efficiency of
312 >  selection criteria in the \WZ, \Zbbbar, \Zjets and \ttjets samples for an integrated luminosity
313    of 1 \invfb.}
314   \label{tab:sel-effA}
315   \end{center}
316   \end{table}
317  
318 <
261 <
262 < %\subsection{Signal extraction}
263 < %\input D0Matrix
264 < \input zjetbackground
265 <
266 <
267 < \section{Systematic uncertainties}
268 < \input Sys
269 <
270 <
271 < \begin{figure}[bt]
272 <  \begin{center}
273 <  \scalebox{0.8}{\includegraphics{figs/met_by_channel.eps}}
274 <  \caption{Missing transverse mass for the four signal categories.
275 <    The distributions  show the number of expected events
276 <    for $1 fb^{-1}$. Only events with 81.1 GeV $< M_Z < $ 101.1 \gev
277 <    are shown. All selection cuts are applied.}
278 <  \label{fig:met}
279 <  \end{center}
280 < \end{figure}
281 <
282 < \begin{figure}[bt]
283 <  \begin{center}
284 <  \scalebox{0.8}{\includegraphics{figs/mtw_by_channel.eps}}
285 <  \caption{W transverse mass for the four signal categories.
286 <    The distributions  show the number of expected events
287 <    for $1 fb^{-1}$. Only events with 81.1 GeV $< M_Z < $ 101.1 GeV are shown.
288 <    All selection cuts are applied.}
289 <  \label{fig:mtw}
290 <  \end{center}
291 < \end{figure}
292 <
293 <
294 <
295 <
296 < \begin{table}[tbp]
318 > \begin{table}[p]
319   \begin{center}
320 < \begin{tabular}{lccccc}
320 > \begin{tabular}{l|ccccc}
321   \hline \hline
322 < & \multicolumn{5}{c}{$Z \to ee $} \\
323 <   &  $W \to e$
324 <   &  $W \to \mu$
325 <   &  $W \to \tau \to e$
326 <   &  $W \to \tau \to \mu$
327 <   &  $W \to \tau \to hadrons$
322 >   & \multicolumn{5}{c}{$\Z \to ee$ and \W decay modes below} \\
323 > Reconstruction channel  &  $e \nu$
324 >   &  $\mu \nu $
325 >   &  $\tau \nu \to e \nu \nu  $
326 >   &  $\tau \nu \to \mu \nu \nu $
327 >   &  $\tau \nu \to {\rm hadrons~} \nu$
328   \\ \hline
329 < $3e$       &  17.4 \%  &  0.0319 \%  &  6.42 \%  &  0 \%  &  0.162 \% \\
330 < $2e1\mu$   &  0 \%  &  18.6 \%  &  0 \%  &  5.53 \%  &  0.0485 \% \\
331 < $2\mu1e$   &  0 \%  &  0 \%  &  0 \%  &  0 \%  &  0 \% \\
332 < $3\mu$     &  0 \%  &  0 \%  &  0 \%  &  0 \%  &  0 \% \\
333 < \hline \hline
334 < & \multicolumn{5}{c}{$Z \to \mu\mu $} \\
335 <   &  $W \to e$
336 <   &  $W \to \mu$
337 <   &  $W \to \tau \to e$
338 <   &  $W \to \tau \to \mu$
339 <   &  $W \to \tau \to hadrons$
329 > $3e$       &  17.4\%  &  0.0319\%  &  6.42\%  &  0\%  &  0.162\% \\
330 > $2e1\mu$   &  0\%  &  18.6\%  &  0\%  &  5.53\%  &  0.0485\% \\
331 > $2\mu1e$   &  0\%  &  0\%  &  0\%  &  0\%  &  0\% \\
332 > $3\mu$     &  0\%  &  0\%  &  0\%  &  0\%  &  0\% \\
333 > \hline \hline
334 >
335 > & \multicolumn{5}{c}{$\Z \to \mu\mu$ and \W decay modes below} \\
336 > Reconstruction channel  &  $e\nu$
337 >   &  $\mu\nu$
338 >   &  $\tau\nu \to e\nu\nu$
339 >   &  $\tau\nu \to \mu\nu\nu$
340 >   &  $\tau\nu \to {\rm hadrons~}\nu$
341   \\ \hline
342 < $3e$        &  0 \%  &  0 \%  &  0 \%  &  0 \%  &  0 \% \\
343 < $2e1\mu$   &  0.0104 \%  &  0 \%  &  0 \%  &  0 \%  &  0 \% \\
344 < $2\mu1e$   &  19.6 \%  &  0.0208 \%  &  5.56 \%  &  0 \%  &  0.18 \% \\
345 < $3\mu$     &  0 \%  &  23.4 \%  &  0.0573 \%  &  6.77 \%  &  0.0164 \% \\
342 > $3e$        &  0\%  &  0\%  &  0\%  &  0\%  &  0\% \\
343 > $2e1\mu$   &  0.0104\%  &  0\%  &  0\%  &  0\%  &  0\% \\
344 > $2\mu1e$   &  19.6\%  &  0.0208\%  &  5.56\%  &  0\%  &  0.18\% \\
345 > $3\mu$     &  0\%  &  23.4\%  &  0.0573\%  &  6.77\%  &  0.0164\% \\
346   \hline \hline
347   \end{tabular}
348   \end{center}
349   \caption{Selection efficiency for signal events in the four selection channels for the different
350    generated \W and \Z decay channels.}
351   \label{tab:wz-effimatrix}
329 \end{table}
330
352  
353 < \begin{table}[tbp]
353 > %\end{table}
354 > %\begin{table}[tbp]
355   \begin{center}
356   \begin{tabular}{llcc} \hline
357 <  & & \multicolumn{2}{c}{Generated decay:} \\
358 <  & & \multicolumn{2}{c}{$Z \to ee $} \\
359 < Selection channel  &    &  $W \to e$   &  $W \to \mu$ \\ \hline
357 >  & & \multicolumn{2}{c}{Generated decay} \\
358 >  & & \multicolumn{2}{c}{$\Z \to ee $} \\
359 > Selection channel  &    &  $\W \to e\nu$   &  $\W \to \mu\nu$ \\
360   \hline \hline
361   \multicolumn{4}{c}{all} \\ \hline
362 < $3e$        & all & 1644         & 3    \\
363 < $3e$        & matched Z & 0.937+/-0.00598 & 1+/-0\\
364 < $3e$        & matched W & 0.915+/-0.00688 & 0+/--1\\
365 < $3e$        & matched WZ & 0.914+/-0.00691 & 0+/--1\\
366 < \hline \hline
367 < \multicolumn{4}{c}{exactly 1 W lepton candidate} \\ \hline
368 < $3e$        & all & 1602         & 0    \\
369 < $3e$        & matched Z & 0.938+/-0.00604 & -1+/--1\\
370 < $3e$        & matched W & 0.915+/-0.00696 & -1+/--1\\
371 < $3e$        & matched WZ & 0.914+/-0.00699 & -1+/--1\\
372 < \hline \hline
373 < \multicolumn{4}{c}{more than 1 W lepton candidate} \\ \hline
374 < $3e$        & all & 42   & 3    \\
375 < $3e$        & matched Z & 0.929+/-0.0397 & 1+/-0\\
376 < $3e$        & matched W & 0.905+/-0.0453 & 0+/--1\\
377 < $3e$        & matched WZ & 0.905+/-0.0453 & 0+/--1\\
362 > $3e$        & all & 1644 events         & 3 events    \\
363 > $3e$        & matched \Z & 93$\pm$1\% & 100\%\\
364 > $3e$        & matched \W & 92$\pm$1\% & 0\\
365 > $3e$        & matched \WZ & 91$\pm$1\% & 0\\
366 > \hline \hline
367 >
368 > \multicolumn{4}{c}{exactly 1 \W lepton candidate} \\ \hline
369 > $3e$        & all & 1602  events       & 0 events    \\
370 > $3e$        & matched \Z & 94$\pm$1\% & 0\\
371 > $3e$        & matched \W & 92$\pm$1\% & 0\\
372 > $3e$        & matched \WZ & 91$\pm$1\% & 0\\
373 > \hline \hline
374 >
375 > \multicolumn{4}{c}{more than 1 \W lepton candidate} \\ \hline
376 > $3e$        & all & 42 events  & 3 events   \\
377 > $3e$        & matched \Z & 93$\pm$4\% & 100\%\\
378 > $3e$        & matched \W & 91 $\pm$5\% & 0\\
379 > $3e$        & matched \WZ & 91$\pm$5\% & 0\\
380   \hline \hline
381 +
382   \multicolumn{4}{c}{all} \\ \hline
383 < $2e1\mu$   & all & 0     & 1746 \\
384 < $2e1\mu$   & matched Z & -1+/--1 & 0.999+/-0.000573\\
385 < $2e1\mu$   & matched W & -1+/--1 & 1+/-0\\
386 < $2e1\mu$   & matched WZ & -1+/--1 & 0.999+/-0.000573\\
387 < \hline \hline
388 < \multicolumn{4}{c}{exactly 1 W lepton candidate} \\ \hline
389 < $2e1\mu$   & all & 0     & 1715 \\
390 < $2e1\mu$   & matched Z & -1+/--1 & 0.999+/-0.000583\\
391 < $2e1\mu$   & matched W & -1+/--1 & 1+/-0\\
392 < $2e1\mu$   & matched WZ & -1+/--1 & 0.999+/-0.000583\\
383 > $2e1\mu$   & all & 0  events   & 1746 events \\
384 > $2e1\mu$   & matched \Z & 0 & 100\%\\
385 > $2e1\mu$   & matched \W & 0 & 100\%\\
386 > $2e1\mu$   & matched \WZ & 0 & 100\%\\
387 > \hline \hline
388 >
389 > \multicolumn{4}{c}{exactly 1 \W lepton candidate} \\ \hline
390 > $2e1\mu$   & all & 0 events    & 1715 events \\
391 > $2e1\mu$   & matched \Z & 0 & 100\%\\
392 > $2e1\mu$   & matched \W & 0 & 100\%\\
393 > $2e1\mu$   & matched \WZ & 0 & 100\%\\
394   \hline \hline
395 < \multicolumn{4}{c}{more than 1 W lepton candidate} \\ \hline
395 >
396 > \multicolumn{4}{c}{more than 1 \W lepton candidate} \\ \hline
397   $2e1\mu$   & all & 0     & 31   \\
398 < $2e1\mu$   & matched Z & -1+/--1 & 1+/-0\\
399 < $2e1\mu$   & matched W & -1+/--1 & 1+/-0\\
400 < $2e1\mu$   & matched WZ & -1+/--1 & 1+/-0\\ \hline \hline
398 > $2e1\mu$   & matched \Z & 0 & 100\%\\
399 > $2e1\mu$   & matched \W & 0 & 100\%\\
400 > $2e1\mu$   & matched \WZ & 0 & 100\% \\ \hline \hline
401   \end{tabular}
402   \end{center}
403   \caption{Fractions of events with correctly matched leptons
# Line 385 | Line 412 | $2e1\mu$   & matched WZ & -1+/--1 & 1+/-
412   \begin{center}
413   \begin{tabular}{llcc} \hline
414    & & \multicolumn{2}{c}{Generated decay:} \\
415 < & & \multicolumn{2}{c}{$Z \to \mu\mu $} \\
416 < Selection channel  &    &  $W \to e$   &  $W \to \mu$
417 < \\ \hline
415 > & & \multicolumn{2}{c}{$\Z \to \mu\mu $} \\
416 > Selection channel  &    &  $\W \to e\nu$   &  $\W \to \mu\nu$
417 > \\
418   \hline \hline
419   \multicolumn{4}{c}{all} \\ \hline
420 < $2\mu1e$   & all & 1895  & 2    \\
421 < $2\mu1e$   & matched Z & 1+/-0 & 1+/-0\\
422 < $2\mu1e$   & matched W & 0.985+/-0.00282 & 0+/--1\\
423 < $2\mu1e$   & matched WZ & 0.985+/-0.00282 & 0+/--1\\
424 < \hline \hline
425 < \multicolumn{4}{c}{exactly 1 W lepton candidate} \\ \hline
426 < $2\mu1e$   & all & 1847  & 0    \\
427 < $2\mu1e$   & matched Z & 1+/-0 & -1+/--1\\
428 < $2\mu1e$   & matched W & 0.986+/-0.00274 & -1+/--1\\
429 < $2\mu1e$   & matched WZ & 0.986+/-0.00274 & -1+/--1\\
430 < \hline \hline
431 < \multicolumn{4}{c}{more than 1 W lepton candidate} \\ \hline
432 < $2\mu1e$   & all & 48    & 2    \\
433 < $2\mu1e$   & matched Z & 1+/-0 & 1+/-0\\
434 < $2\mu1e$   & matched W & 0.938+/-0.0349 & 0+/--1\\
435 < $2\mu1e$   & matched WZ & 0.938+/-0.0349 & 0+/--1\\
420 > $2\mu1e$   & all & 1895 events  & 2 events   \\
421 > $2\mu1e$   & matched \Z & 100\% & 100\%\\
422 > $2\mu1e$   & matched \W & 99$\pm$1\% & 0\\
423 > $2\mu1e$   & matched \WZ & 99$\pm$1\% & 0\\
424 > \hline \hline
425 >
426 > \multicolumn{4}{c}{exactly 1 \W lepton candidate} \\ \hline
427 > $2\mu1e$   & all & 1847 events & 0 events    \\
428 > $2\mu1e$   & matched \Z & 100\% & 0\\
429 > $2\mu1e$   & matched \W & 99$\pm$1\% & 0\\
430 > $2\mu1e$   & matched \WZ & 99$\pm$1\% & 0\\
431 > \hline \hline
432 >
433 > \multicolumn{4}{c}{more than 1 \W lepton candidate} \\ \hline
434 > $2\mu1e$   & all & 48 events   & 2 events    \\
435 > $2\mu1e$   & matched \Z & 100\% & 100\%\\
436 > $2\mu1e$   & matched \W & 94$\pm$3.5\%& 0\\
437 > $2\mu1e$   & matched \WZ & 94$\pm$3.5\% & 0\\
438   \hline \hline
439 +
440   \multicolumn{4}{c}{all} \\ \hline
441 < $3\mu$     & all & 0     & 2251 \\
442 < $3\mu$     & matched Z & -1+/--1 & 0.943+/-0.00488\\
443 < $3\mu$     & matched W & -1+/--1 & 0.933+/-0.00526\\
444 < $3\mu$     & matched WZ & -1+/--1 & 0.933+/-0.00526\\
445 < \hline \hline
446 < \multicolumn{4}{c}{exactly 1 W lepton candidate} \\ \hline
447 < $3\mu$     & all & 0     & 2207 \\
448 < $3\mu$     & matched Z & -1+/--1 & 0.944+/-0.0049\\
449 < $3\mu$     & matched W & -1+/--1 & 0.934+/-0.00529\\
450 < $3\mu$     & matched WZ & -1+/--1 & 0.934+/-0.00529\\
451 < \hline \hline
452 < \multicolumn{4}{c}{more than 1 W lepton candidate} \\ \hline
453 < $3\mu$     & all & 0     & 44   \\
454 < $3\mu$     & matched Z & -1+/--1 & 0.909+/-0.0433\\
455 < $3\mu$     & matched W & -1+/--1 & 0.909+/-0.0433\\
456 < $3\mu$     & matched WZ & -1+/--1 & 0.909+/-0.0433\\ \hline \hline
441 > $3\mu$     & all & 0 events   & 2251 events \\
442 > $3\mu$     & matched \Z & 0 & 94$\pm$1\%\\
443 > $3\mu$     & matched \W & 0 & 93$\pm$1\%\\
444 > $3\mu$     & matched \WZ & 0 & 93$\pm$1\%\\
445 > \hline \hline
446 >
447 > \multicolumn{4}{c}{exactly 1 \W lepton candidate} \\ \hline
448 > $3\mu$     & all & 0 events    & 2207 events \\
449 > $3\mu$     & matched \Z & 0 & 94$\pm$1\%\\
450 > $3\mu$     & matched \W & 0 & 93$\pm$1\%\\
451 > $3\mu$     & matched \WZ & 0 & 93$\pm$1\%\\
452 > \hline \hline
453 >
454 > \multicolumn{4}{c}{more than 1 \W lepton candidate} \\ \hline
455 > $3\mu$     & all & 0 events    & 44 events  \\
456 > $3\mu$     & matched \Z & 0 & 91$\pm$4\%\\
457 > $3\mu$     & matched \W & 0 & 91$\pm$4\%\\
458 > $3\mu$     & matched \WZ & 0 & 91$\pm$4\%\\ \hline \hline
459   \end{tabular}
460   \end{center}
461   \caption{Fractions of MC \WZ events with correctly matched leptons
# Line 432 | Line 464 | $3\mu$     & matched WZ & -1+/--1 & 0.90
464   \label{tab:wz-matcheffi-Zmumu}
465   \end{table}
466  
467 +
468 + %\subsection{Signal extraction}
469 + %\input D0Matrix
470 + \input zjetbackground
471 +
472 +
473 + \subsection{Complementary studies: can we use the neutrino?}
474 +
475 + In $\WZ \to  \ell^{\pm}\nu \ellell (\ell=e,\mu)$ events, the neutrino
476 + coming from the \W-boson decay leaves the detector with a significant
477 + amount of energy, which should reflect in a large transverse missing
478 + energy measurement. On the other side, no large MET is expected for
479 + the  most  important background categories, especially \Zjets,
480 + \Zbbbar, \ZZ and \Zgamma. This expectation is confirmed, as can be
481 + seen in Figure~\ref{fig:met}.
482 +
483 + Another variable sensitive to the presence of the neutrino
484 + is the W transverse mass $m_T^W$, obtained by combining the missing
485 + energy vector and the lepton associated to the \W-boson decay.
486 + The distribution of $m_T^W$ is shown in Figure~\ref{fig:mtw}.
487 + The signal yield could be extracted from that distribution.
488 + This requires however additional studies and it has not been
489 + done at this stage.
490 +
491 +
492 + \section{Systematic uncertainties}
493 + \input Sys
494 +
495 +
496 + \begin{figure}[bt]
497 +  \begin{center}
498 +  \scalebox{0.8}{\includegraphics{figs/met_by_channel.eps}}
499 +  \caption{Missing transverse energy for the four signal categories.
500 +    The distributions  show the number of expected events
501 +    for $1 fb^{-1}$. Only events with 81 GeV $< M_Z < $ 101 \gev
502 +    are shown. All selection cuts are applied.}
503 +  \label{fig:met}
504 +  \end{center}
505 + \end{figure}
506 +
507 + \begin{figure}[bt]
508 +  \begin{center}
509 +  \scalebox{0.8}{\includegraphics{figs/mtw_by_channel.eps}}
510 +  \caption{\W transverse mass for the four signal categories.
511 +    The distributions  show the number of expected events
512 +    for $1 fb^{-1}$. Only events with 81 GeV $< M_Z < $ 101 GeV are shown.
513 +    All selection cuts are applied.}
514 +  \label{fig:mtw}
515 +  \end{center}
516 + \end{figure}
517 +
518 +
519 +
520 +
521 +

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