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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  
# Line 51 | Line 46 | $3\mu$     &   HLTSingleMuonIso
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: the left plot
50 <    shows the sum of calorimetric energy in a $\Delta R=0.3$ cone
51 <    around the muon candidate; the right plot shows the sum of
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.
# Line 82 | 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 98 | 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, as can be seen in Figure~\ref{fig:wl_IP_SvsCut}.
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 cut value on the \W-boson lepton impact parameter
115 <    significance. All other cuts but the cut on this variable
116 <    are applied.
117 < %    Only events with 81.1 GeV $< M_Z < $ 101.1 \gev
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}
# Line 124 | Line 124 | in significance there, as can be seen in
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 the cut value on
128 <    the \W-boson lepton impact parameter significance. All other cuts but
129 <    the cut on this variable are applied.
130 < %    Only events with 81.1 GeV $< M_Z < $ 101.1 \gev are considered.
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}
# Line 138 | Line 138 | in significance there, as can be seen in
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 166 | 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 178 | 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 187 | 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.
192 < 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
227 < to the \W-decay and any of the two muons associated to the \Z-decay be greater than
228 < 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}
# Line 250 | Line 254 | muons from $W \to \tau \to e/\mu$ decays
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
266 < Overall efficiency  & 5.77899 \% & 0.0240354 \% & 0.00409279 \% & 0.0185605 \% \\
267 < \hline
268 < \end{tabular}
269 < \begin{tabular}{lcccc} \hline
270 < \multicolumn{5}{c}{ {\bf $2e1\mu$ Channel}} \\ \hline  \hline
271 < Step   & WZ  & bbll  & Z+jets  & \ttjets\\ \hline
272 < All events       & 546   & 72770.4       & 1.2679e+06    & 17556.1 \\
273 < Found $Z \to ee$         & 204.969 (37.5401 \%)  & 27800.5 (38.203 \%)   & 502344 (39.62 \%)     & 2920.59 (16.6357 \%) \\
274 < Found $W \to \mu$        & 47.9099 (23.3743 \%)  & 747.725 (2.68961 \%)  & 2194.09 (0.436771 \%)         & 56.7645 (1.9436 \%) \\
275 < W Lepton Pt cut          & 37.0973 (77.4313 \%)  & 9.63467 (1.28853 \%)  & 9.57604 (0.436446 \%)         & 17.5382 (30.8965 \%) \\
276 < Passes HLT               & 36.1929 (97.5623 \%)  & 9.26411 (96.1538 \%)  & 8.32189 (86.9033 \%)  & 15.2488 (86.9457 \%) \\
277 < Z mass window    & 32.5166 (89.8425 \%)  & 8.15242 (88 \%)       & 7.31467 (87.8968 \%)  & 4.91533 (32.2343 \%) \\ \hline
278 < Overall efficiency  & 5.95542 \% & 0.0112029 \% & 0.000576911 \% & 0.0279978 \% \\
279 < \hline
280 < \end{tabular}
281 <
282 < \begin{tabular}{lcccc} \hline
283 < \multicolumn{5}{c}{ {\bf $2\mu1e$ 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 $W \to e$          & 48.7553 (20.8579 \%)  & 213.519 (0.669562 \%)         & 701.695 (0.121557 \%)         & 15.1085 (0.543704 \%) \\
288 < W Lepton Pt cut                  & 40.6556 (83.3871 \%)  & 50.6191 (23.707 \%)   & 464.493 (66.196 \%)   & 10.2745 (68.0047 \%) \\
289 < $\Delta R(e,\mu)$ cut    & 40.5573 (99.7582 \%)  & 23.3456 (46.1201 \%)  & 92.9813 (20.0178 \%)  & 7.14967 (69.5865 \%) \\
290 < Passes HLT                       & 39.4171 (97.1886 \%)  & 23.1973 (99.3651 \%)  & 88.7791 (95.4806 \%)  & 6.6245 (92.6546 \%) \\
291 < Z mass window    & 35.5638 (90.2244 \%)  & 18.8988 (81.4696 \%)  & 50.2509 (56.6022 \%)  & 2.84083 (42.8837 \%) \\ \hline
292 < Overall efficiency  & 6.51352 \% & 0.0259704 \% & 0.00396331 \% & 0.0161814 \% \\
293 < \hline
294 < \end{tabular}
295 <
296 <
297 < \begin{tabular}{lcccc} \hline
298 < \multicolumn{5}{c}{ {\bf $3\mu$ Channel}} \\ \hline  \hline
299 < Step   & WZ  & bbll  & Z+jets  & TTbar+jets\\ \hline
300 < All events       & 546   & 72770.4       & 1.2679e+06    & 17556.1 \\
297 < Found $Z \to \mu\mu$     & 233.75 (42.8114 \%)   & 31889.4 (43.8219 \%)  & 577257 (45.5284 \%)   & 2778.81 (15.8282 \%) \\
298 < Found $W \to \mu$        & 57.7986 (24.7267 \%)  & 810.721 (2.54229 \%)  & 2520.69 (0.436668 \%)         & 35.3061 (1.27054 \%) \\
299 < W Lepton Pt cut                  & 44.2533 (76.5646 \%)  & 8.89355 (1.09699 \%)  & 1.84115 (0.0730414 \%)        & 1.683 (4.76688 \%) \\
300 < Passes HLT                       & 43.9977 (99.4225 \%)  & 8.89355 (100 \%)      & 1.84115 (100 \%)      & 1.683 (100 \%) \\
301 < Z mass window    & 40.0462 (91.0188 \%)  & 7.78185 (87.5 \%)     & 1.84115 (100 \%)      & 1.15783 (68.7957 \%) \\ \hline
302 < Overall efficiency  & 7.33446 \% & 0.0106937 \% & 0.000145212 \% & 0.00659501 \% \\
257 > \begin{tabular}{lcc|cc|cc|cc|c} \hline \hline
258 > \multicolumn{9}{c}{ {\bf $3e$ Channel}} \\ \hline  \hline
259 > Step                                 & \WZ  & $\epsilon$ & $b\bar{b}\ell\ell$  & $\epsilon$ & $\Z+jets$  & $\epsilon$ & $t\bar{t}+jets$  & $\epsilon$ \\ \hline
260 > All events                       & 546   &                    & 72,700 &                     & 1,268,000       &                       & 17,600     &               \\
261 > Found $\Z \to ee$         & 205   & 38\%         & 27,800 & 38\%            & 502,300          & 40\%            & 2,920        & 17\%    \\
262 > Found $\W \to e\nu$    & 42.0  & 21\%         & 171       & 0.6\%           & 309.6               & 0.06\%        & 13.8           & 0.5\%   \\
263 > \W lepton $p_T$ cut    & 34.9  & 83\%          & 23.7     & 14\%            & 86.8                  & 28 \%          &   8.3            & 60\%   \\
264 > Passes HLT                  & 34.7  & 100\%        & 23.6     & 99\%            & 86.8                  &100\%         &   8.3            & 100\%  \\
265 > \Z mass window           & 31.6  & 91\%          & 17.5     & 74\%            & 51.9                  &60\%           &    3.3            & 39\%    \\ \hline
266 > Overall efficiency        &           &  5.8\%        &              &   0.024\%    &                            & 0.0041\%  &                     & 0.019\% \\
267 > \hline\hline
268 >
269 > \multicolumn{9}{c}{ {\bf $2e1\mu$ Channel}} \\ \hline  \hline
270 > Step   & \WZ  & $\epsilon$ & $b\bar{b}\ell\ell$ & $\epsilon$ & $\Z+jets$  & $\epsilon$ & $t\bar{t}+jets$ & $\epsilon$  \\ \hline
271 > All events                        & 546  &             & 72,770 &                 & 1,268,000       &                    & 17,600            &             \\
272 > Found $\Z \to ee$          & 201  & 38\%  & 27,800  & 38\%      &  502,300          &  40\%     &     2,921          &17\% \\
273 > Found $\W \to \mu\nu$ & 47.9 & 23\%  & 748       & 2.7\%      &  2194         &  0.43\%  &      56.8          &1.9\% \\
274 > \W lepton $p_T$ cut      & 37.1 & 77\%  & 9.6        & 1.3\%      &   9.6                  &  0.4\%         &      17.5         &31\% \\
275 > Passes HLT                    & 36.2 & 98\%  & 9.3        & 96\%       &   8.3                  &  87\%    &     15.2   & 87 \%) \\
276 > \Z mass window             & 32.5 & 90\%  & 8.2        &  88\%      &    7.3                 &  88\%            &       4.9         & 32\%) \\ \hline
277 > Overall efficiency          &          & 6.0\% &               & 0.011\% &                           &  0.00058\% &                      &     0.028\% \\
278 > \hline \hline
279 >
280 > \multicolumn{9}{c}{ {\bf $2\mu1e$ Channel}} \\ \hline  \hline
281 > Step   & \WZ   & $\epsilon$ & $b\bar{b}\ell\ell$   & $\epsilon$ & $\Z+jets$   & $\epsilon$ & $t\bar{t}+jets$  & $\epsilon$ \\ \hline
282 > All events       & 546  &   & 72,770   &    & 1,268,000 &    & 17,600 &  \\
283 > Found $\Z \to \mu\mu$     & 234  &43\%&      31,890 & 44\% & 577,200 & 46\%   & 2779 & 16\% \\
284 > Found $\W \to e\nu$          & 48.8 &21\%&    214        & 0.67\%   & 702 & 0.12\%         & 15.1 & 0.54\% \\
285 > \W lepton $p_T$ cut          & 40.7 &83\%&      50.6      & 24\%      & 464.0 & 66\%      & 10.3 & 68\% \\
286 > $\Delta R(e,\mu)$ cut       & 40.6&100\%&      23.3     & 46\%     & 93.0 & 20\%         & 7.1 & 70\%  \\
287 > Passes HLT                       & 39.4 &97\%&        23.2     & 99\%      & 88.8 & 95\%        & 6.6  & 93\%  \\
288 > \Z mass window                & 35.6 & 90\% &          18.9 & 81\%      & 50.3 & 57\%       & 2.8   &44\%  \\ \hline
289 > Overall efficiency              &           &6.5\%  &                  & 0.026\% &           & 0.0040\%  &          & 0.016\% \\
290 > \hline \hline
291 >
292 > \multicolumn{9}{c}{ {\bf $3\mu$ Channel}} \\ \hline  \hline
293 > Step   & \WZ   & $\epsilon$ & ${b\bar{b}\ell\ell}$   & $\epsilon$ & $\Z+jets$   & $\epsilon$ & ${t\bar{t}+jets}$  & $\epsilon$ \\ \hline
294 > All events       & 546 &   & 72,770  &      & 1,268,000  &   & 17,600 &  \\
295 > Found $Z \to \mu\mu$        & 234     & 43\%   & 31,900 & 44\%       & 577,000 & 45\%          & 2779  & 16 \% \\
296 > Found $W \to \mu$             & 58        & 25 \%  & 811      & 2.5\%      & 2521       & 0.44\%       & 35.3   & 1.23 \% \\
297 > W Lepton Pt cut                   & 44.2    & 77 \% & 8.9         & 1.1\%      & 1.8          & 0.07\%        & 1.7     & 4.8 \% \\
298 > Passes HLT                         & 44.0    & 99\%  & 8.9          & 100\%    & 1.8         & 100 \%        & 1.7     & 100 \% \\
299 > Z mass window                   & 40.0    & 91 \%)  & 7.8        & 88\%      & 1.8          & 100 \%        & 1.2     & 69\% \\ \hline
300 > Overall efficiency               &             & 7.3 \% &                & 0.011\% &                & 0.00015\% &            & 0.0065\% \\
301   \hline
302   \end{tabular}
303  
304  
305   \caption{Expected number of signal and background events passing the different
306 <  selections steps in the \WZ, \Zbbbar, \Zjets and \ttjets samples for an integrated luminosity
306 >  selections steps together with the efficiency of each requirement and total efficiency of
307 >  selection criteria in the \WZ, \Zbbbar, \Zjets and \ttjets samples for an integrated luminosity
308    of 1 \invfb.}
309   \label{tab:sel-effA}
310   \end{center}
311   \end{table}
312  
313 <
315 <
316 < %\subsection{Signal extraction}
317 < %\input D0Matrix
318 < \input zjetbackground
319 <
320 <
321 < \section{Systematic uncertainties}
322 < \input Sys
323 <
324 <
325 < \begin{figure}[bt]
326 <  \begin{center}
327 <  \scalebox{0.8}{\includegraphics{figs/met_by_channel.eps}}
328 <  \caption{Missing transverse mass for the four signal categories.
329 <    The distributions  show the number of expected events
330 <    for $1 fb^{-1}$. Only events with 81.1 GeV $< M_Z < $ 101.1 \gev
331 <    are shown. All selection cuts are applied.}
332 <  \label{fig:met}
333 <  \end{center}
334 < \end{figure}
335 <
336 < \begin{figure}[bt]
337 <  \begin{center}
338 <  \scalebox{0.8}{\includegraphics{figs/mtw_by_channel.eps}}
339 <  \caption{W transverse mass for the four signal categories.
340 <    The distributions  show the number of expected events
341 <    for $1 fb^{-1}$. Only events with 81.1 GeV $< M_Z < $ 101.1 GeV are shown.
342 <    All selection cuts are applied.}
343 <  \label{fig:mtw}
344 <  \end{center}
345 < \end{figure}
346 <
347 <
348 <
349 <
350 < \begin{table}[tbp]
313 > \begin{table}[p]
314   \begin{center}
315 < \begin{tabular}{lccccc}
315 > \begin{tabular}{l|ccccc}
316   \hline \hline
317 < & \multicolumn{5}{c}{$Z \to ee $} \\
318 <   &  $W \to e$
319 <   &  $W \to \mu$
320 <   &  $W \to \tau \to e$
321 <   &  $W \to \tau \to \mu$
322 <   &  $W \to \tau \to hadrons$
317 >   & \multicolumn{5}{c}{$\Z \to ee$ and \W decay modes below} \\
318 > Reconstruction channel  &  $e \nu$
319 >   &  $\mu \nu $
320 >   &  $\tau \nu \to e \nu \nu  $
321 >   &  $\tau \nu \to \mu \nu \nu $
322 >   &  $\tau \nu \to {\rm hadrons~} \nu$
323   \\ \hline
324   $3e$       &  17.4 \%  &  0.0319 \%  &  6.42 \%  &  0 \%  &  0.162 \% \\
325   $2e1\mu$   &  0 \%  &  18.6 \%  &  0 \%  &  5.53 \%  &  0.0485 \% \\
326   $2\mu1e$   &  0 \%  &  0 \%  &  0 \%  &  0 \%  &  0 \% \\
327   $3\mu$     &  0 \%  &  0 \%  &  0 \%  &  0 \%  &  0 \% \\
328   \hline \hline
329 < & \multicolumn{5}{c}{$Z \to \mu\mu $} \\
330 <   &  $W \to e$
331 <   &  $W \to \mu$
332 <   &  $W \to \tau \to e$
333 <   &  $W \to \tau \to \mu$
334 <   &  $W \to \tau \to hadrons$
329 >
330 > & \multicolumn{5}{c}{$\Z \to \mu\mu$ and \W decay modes below} \\
331 > Reconstruction channel  &  $e\nu$
332 >   &  $\mu\nu$
333 >   &  $\tau\nu \to e\nu\nu$
334 >   &  $\tau\nu \to \mu\nu\nu$
335 >   &  $\tau\nu \to {\rm hadrons~}\nu$
336   \\ \hline
337   $3e$        &  0 \%  &  0 \%  &  0 \%  &  0 \%  &  0 \% \\
338   $2e1\mu$   &  0.0104 \%  &  0 \%  &  0 \%  &  0 \%  &  0 \% \\
# Line 380 | Line 344 | $3\mu$     &  0 \%  &  23.4 \%  &  0.057
344   \caption{Selection efficiency for signal events in the four selection channels for the different
345    generated \W and \Z decay channels.}
346   \label{tab:wz-effimatrix}
383 \end{table}
384
347  
348 < \begin{table}[tbp]
348 > %\end{table}
349 > %\begin{table}[tbp]
350   \begin{center}
351   \begin{tabular}{llcc} \hline
352 <  & & \multicolumn{2}{c}{Generated decay:} \\
353 <  & & \multicolumn{2}{c}{$Z \to ee $} \\
354 < Selection channel  &    &  $W \to e$   &  $W \to \mu$ \\ \hline
352 >  & & \multicolumn{2}{c}{Generated decay} \\
353 >  & & \multicolumn{2}{c}{$\Z \to ee $} \\
354 > Selection channel  &    &  $\W \to e\nu$   &  $\W \to \mu\nu$ \\
355   \hline \hline
356   \multicolumn{4}{c}{all} \\ \hline
357 < $3e$        & all & 1644         & 3    \\
358 < $3e$        & matched Z & 0.937+/-0.00598 & 1+/-0\\
359 < $3e$        & matched W & 0.915+/-0.00688 & 0+/--1\\
360 < $3e$        & matched WZ & 0.914+/-0.00691 & 0+/--1\\
361 < \hline \hline
362 < \multicolumn{4}{c}{exactly 1 W lepton candidate} \\ \hline
363 < $3e$        & all & 1602         & 0    \\
364 < $3e$        & matched Z & 0.938+/-0.00604 & -1+/--1\\
365 < $3e$        & matched W & 0.915+/-0.00696 & -1+/--1\\
366 < $3e$        & matched WZ & 0.914+/-0.00699 & -1+/--1\\
367 < \hline \hline
368 < \multicolumn{4}{c}{more than 1 W lepton candidate} \\ \hline
369 < $3e$        & all & 42   & 3    \\
370 < $3e$        & matched Z & 0.929+/-0.0397 & 1+/-0\\
371 < $3e$        & matched W & 0.905+/-0.0453 & 0+/--1\\
372 < $3e$        & matched WZ & 0.905+/-0.0453 & 0+/--1\\
357 > $3e$        & all & 1644 events         & 3 events    \\
358 > $3e$        & matched \Z & 93$\pm$1\% & 100\%\\
359 > $3e$        & matched \W & 92$\pm$1\% & 0\\
360 > $3e$        & matched \WZ & 91$\pm$1\% & 0\\
361 > \hline \hline
362 >
363 > \multicolumn{4}{c}{exactly 1 \W lepton candidate} \\ \hline
364 > $3e$        & all & 1602  events       & 0 events    \\
365 > $3e$        & matched \Z & 94$\pm$1\% & 0\\
366 > $3e$        & matched \W & 92$\pm$1\% & 0\\
367 > $3e$        & matched \WZ & 91$\pm$1\% & 0\\
368 > \hline \hline
369 >
370 > \multicolumn{4}{c}{more than 1 \W lepton candidate} \\ \hline
371 > $3e$        & all & 42 events  & 3 events   \\
372 > $3e$        & matched \Z & 93$\pm$4\% & 100\%\\
373 > $3e$        & matched \W & 91 $\pm$5\% & 0\\
374 > $3e$        & matched \WZ & 91$\pm$5\% & 0\\
375   \hline \hline
376 +
377   \multicolumn{4}{c}{all} \\ \hline
378 < $2e1\mu$   & all & 0     & 1746 \\
379 < $2e1\mu$   & matched Z & -1+/--1 & 0.999+/-0.000573\\
380 < $2e1\mu$   & matched W & -1+/--1 & 1+/-0\\
381 < $2e1\mu$   & matched WZ & -1+/--1 & 0.999+/-0.000573\\
382 < \hline \hline
383 < \multicolumn{4}{c}{exactly 1 W lepton candidate} \\ \hline
384 < $2e1\mu$   & all & 0     & 1715 \\
385 < $2e1\mu$   & matched Z & -1+/--1 & 0.999+/-0.000583\\
386 < $2e1\mu$   & matched W & -1+/--1 & 1+/-0\\
387 < $2e1\mu$   & matched WZ & -1+/--1 & 0.999+/-0.000583\\
378 > $2e1\mu$   & all & 0  events   & 1746 events \\
379 > $2e1\mu$   & matched \Z & 0 & 100\%\\
380 > $2e1\mu$   & matched \W & 0 & 100\%\\
381 > $2e1\mu$   & matched \WZ & 0 & 100\%\\
382 > \hline \hline
383 >
384 > \multicolumn{4}{c}{exactly 1 \W lepton candidate} \\ \hline
385 > $2e1\mu$   & all & 0 events    & 1715 events \\
386 > $2e1\mu$   & matched \Z & 0 & 100\%\\
387 > $2e1\mu$   & matched \W & 0 & 100\%\\
388 > $2e1\mu$   & matched \WZ & 0 & 100\%\\
389   \hline \hline
390 < \multicolumn{4}{c}{more than 1 W lepton candidate} \\ \hline
390 >
391 > \multicolumn{4}{c}{more than 1 \W lepton candidate} \\ \hline
392   $2e1\mu$   & all & 0     & 31   \\
393 < $2e1\mu$   & matched Z & -1+/--1 & 1+/-0\\
394 < $2e1\mu$   & matched W & -1+/--1 & 1+/-0\\
395 < $2e1\mu$   & matched WZ & -1+/--1 & 1+/-0\\ \hline \hline
393 > $2e1\mu$   & matched \Z & 0 & 100\%\\
394 > $2e1\mu$   & matched \W & 0 & 100\%\\
395 > $2e1\mu$   & matched \WZ & 0 & 100\% \\ \hline \hline
396   \end{tabular}
397   \end{center}
398   \caption{Fractions of events with correctly matched leptons
# Line 439 | Line 407 | $2e1\mu$   & matched WZ & -1+/--1 & 1+/-
407   \begin{center}
408   \begin{tabular}{llcc} \hline
409    & & \multicolumn{2}{c}{Generated decay:} \\
410 < & & \multicolumn{2}{c}{$Z \to \mu\mu $} \\
411 < Selection channel  &    &  $W \to e$   &  $W \to \mu$
412 < \\ \hline
410 > & & \multicolumn{2}{c}{$\Z \to \mu\mu $} \\
411 > Selection channel  &    &  $\W \to e\nu$   &  $\W \to \mu\nu$
412 > \\
413   \hline \hline
414   \multicolumn{4}{c}{all} \\ \hline
415 < $2\mu1e$   & all & 1895  & 2    \\
416 < $2\mu1e$   & matched Z & 1+/-0 & 1+/-0\\
417 < $2\mu1e$   & matched W & 0.985+/-0.00282 & 0+/--1\\
418 < $2\mu1e$   & matched WZ & 0.985+/-0.00282 & 0+/--1\\
419 < \hline \hline
420 < \multicolumn{4}{c}{exactly 1 W lepton candidate} \\ \hline
421 < $2\mu1e$   & all & 1847  & 0    \\
422 < $2\mu1e$   & matched Z & 1+/-0 & -1+/--1\\
423 < $2\mu1e$   & matched W & 0.986+/-0.00274 & -1+/--1\\
424 < $2\mu1e$   & matched WZ & 0.986+/-0.00274 & -1+/--1\\
425 < \hline \hline
426 < \multicolumn{4}{c}{more than 1 W lepton candidate} \\ \hline
427 < $2\mu1e$   & all & 48    & 2    \\
428 < $2\mu1e$   & matched Z & 1+/-0 & 1+/-0\\
429 < $2\mu1e$   & matched W & 0.938+/-0.0349 & 0+/--1\\
430 < $2\mu1e$   & matched WZ & 0.938+/-0.0349 & 0+/--1\\
415 > $2\mu1e$   & all & 1895 events  & 2 events   \\
416 > $2\mu1e$   & matched \Z & 100\% & 100\%\\
417 > $2\mu1e$   & matched \W & 99$\pm$1\% & 0\\
418 > $2\mu1e$   & matched \WZ & 99$\pm$1\% & 0\\
419 > \hline \hline
420 >
421 > \multicolumn{4}{c}{exactly 1 \W lepton candidate} \\ \hline
422 > $2\mu1e$   & all & 1847 events & 0 events    \\
423 > $2\mu1e$   & matched \Z & 100\% & 0\\
424 > $2\mu1e$   & matched \W & 99$\pm$1\% & 0\\
425 > $2\mu1e$   & matched \WZ & 99$\pm$1\% & 0\\
426 > \hline \hline
427 >
428 > \multicolumn{4}{c}{more than 1 \W lepton candidate} \\ \hline
429 > $2\mu1e$   & all & 48 events   & 2 events    \\
430 > $2\mu1e$   & matched \Z & 100\% & 100\%\\
431 > $2\mu1e$   & matched \W & 94$\pm$3.5\%& 0\\
432 > $2\mu1e$   & matched \WZ & 94$\pm$3.5\% & 0\\
433   \hline \hline
434 +
435   \multicolumn{4}{c}{all} \\ \hline
436 < $3\mu$     & all & 0     & 2251 \\
437 < $3\mu$     & matched Z & -1+/--1 & 0.943+/-0.00488\\
438 < $3\mu$     & matched W & -1+/--1 & 0.933+/-0.00526\\
439 < $3\mu$     & matched WZ & -1+/--1 & 0.933+/-0.00526\\
440 < \hline \hline
441 < \multicolumn{4}{c}{exactly 1 W lepton candidate} \\ \hline
442 < $3\mu$     & all & 0     & 2207 \\
443 < $3\mu$     & matched Z & -1+/--1 & 0.944+/-0.0049\\
444 < $3\mu$     & matched W & -1+/--1 & 0.934+/-0.00529\\
445 < $3\mu$     & matched WZ & -1+/--1 & 0.934+/-0.00529\\
446 < \hline \hline
447 < \multicolumn{4}{c}{more than 1 W lepton candidate} \\ \hline
448 < $3\mu$     & all & 0     & 44   \\
449 < $3\mu$     & matched Z & -1+/--1 & 0.909+/-0.0433\\
450 < $3\mu$     & matched W & -1+/--1 & 0.909+/-0.0433\\
451 < $3\mu$     & matched WZ & -1+/--1 & 0.909+/-0.0433\\ \hline \hline
436 > $3\mu$     & all & 0 events   & 2251 events \\
437 > $3\mu$     & matched \Z & 0 & 94$\pm$1\%\\
438 > $3\mu$     & matched \W & 0 & 93$\pm$1\%\\
439 > $3\mu$     & matched \WZ & 0 & 93$\pm$1\%\\
440 > \hline \hline
441 >
442 > \multicolumn{4}{c}{exactly 1 \W lepton candidate} \\ \hline
443 > $3\mu$     & all & 0 events    & 2207 events \\
444 > $3\mu$     & matched \Z & 0 & 94$\pm$1\%\\
445 > $3\mu$     & matched \W & 0 & 93$\pm$1\%\\
446 > $3\mu$     & matched \WZ & 0 & 93$\pm$1\%\\
447 > \hline \hline
448 >
449 > \multicolumn{4}{c}{more than 1 \W lepton candidate} \\ \hline
450 > $3\mu$     & all & 0 events    & 44 events  \\
451 > $3\mu$     & matched \Z & 0 & 91$\pm$4\%\\
452 > $3\mu$     & matched \W & 0 & 91$\pm$4\%\\
453 > $3\mu$     & matched \WZ & 0 & 91$\pm$4\%\\ \hline \hline
454   \end{tabular}
455   \end{center}
456   \caption{Fractions of MC \WZ events with correctly matched leptons
# Line 486 | Line 459 | $3\mu$     & matched WZ & -1+/--1 & 0.90
459   \label{tab:wz-matcheffi-Zmumu}
460   \end{table}
461  
462 +
463 + %\subsection{Signal extraction}
464 + %\input D0Matrix
465 + \input zjetbackground
466 +
467 +
468 + \subsection{Complementary studies: can we use the neutrino?}
469 +
470 + In $\WZ \to  \ell^{\pm}\nu \ellell (\ell=e,\mu)$ events, the neutrino
471 + coming from the \W-boson decay leaves the detector with a significant
472 + amount of energy, which should reflect in a large transverse missing
473 + energy measurement. On the other side, no large MET is expected for
474 + the  most  important background categories, especially \Zjets,
475 + \Zbbbar, \ZZ and \Zgamma. This expectation is confirmed, as can be
476 + seen in Figure~\ref{fig:met}.
477 +
478 + Another variable sensitive to the presence of the neutrino
479 + is the W transverse mass $m_T^W$, obtained by combining the missing
480 + energy vector and the lepton associated to the \W-boson decay.
481 + The distribution of $m_T^W$ is shown in Figure~\ref{fig:mtw}.
482 + The signal yield could be extracted from that distribution.
483 + This requires however additional studies and it has not been
484 + done at this stage.
485 +
486 +
487 + \section{Systematic uncertainties}
488 + \input Sys
489 +
490 +
491 + \begin{figure}[bt]
492 +  \begin{center}
493 +  \scalebox{0.8}{\includegraphics{figs/met_by_channel.eps}}
494 +  \caption{Missing transverse mass for the four signal categories.
495 +    The distributions  show the number of expected events
496 +    for $1 fb^{-1}$. Only events with 81 GeV $< M_Z < $ 101 \gev
497 +    are shown. All selection cuts are applied.}
498 +  \label{fig:met}
499 +  \end{center}
500 + \end{figure}
501 +
502 + \begin{figure}[bt]
503 +  \begin{center}
504 +  \scalebox{0.8}{\includegraphics{figs/mtw_by_channel.eps}}
505 +  \caption{\W transverse mass for the four signal categories.
506 +    The distributions  show the number of expected events
507 +    for $1 fb^{-1}$. Only events with 81 GeV $< M_Z < $ 101 GeV are shown.
508 +    All selection cuts are applied.}
509 +  \label{fig:mtw}
510 +  \end{center}
511 + \end{figure}
512 +
513 +
514 +
515 +
516 +

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