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Revision 1.12 by ymaravin, Mon Jun 23 10:00:12 2008 UTC vs.
Revision 1.16 by vuko, Fri Jun 27 17:14:35 2008 UTC

# Line 36 | 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 that have been retained  by
41 <  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 86 | Line 85 | within a $\Delta R = 0.25$ cone around t
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 102 | Line 104 | and not for electrons. For electron cand
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}.
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}
# Line 111 | Line 114 | Fig.~\ref{fig:wl_IP_SvsCut}.
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 81.1 GeV $< M_Z < $ 101.1 \gev
117 > %    Only events with 81 GeV $< M_Z < $ 101 \gev
118   %    are considered.
119    }
120    \label{fig:wl_IP_eff}
# Line 124 | Line 127 | Fig.~\ref{fig:wl_IP_SvsCut}.
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 81.1 GeV $< M_Z < $ 101.1 \gev are considered.
130 > %    Only events with 81 GeV $< M_Z < $ 101 \gev are considered.
131    }
132    \label{fig:wl_IP_SvsCut}
133    \end{center}
# Line 135 | Line 138 | Fig.~\ref{fig:wl_IP_SvsCut}.
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 163 | 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 175 | 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 184 | 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.
189 < 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.
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}.
# Line 206 | Line 208 | veto on the presence of a second Z helps
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
225 < to the \W-decay and any of the two muons associated to the \Z-decay be greater than
226 < 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 is given 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}.
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.
244 <
245 < Tables~ref\label{tab:wz-matcheffi-Zee} and \label{tab:wz-matcheffi-Zmumu} show
246 < the fraction of reconstructed \WZ events with with correclty matched leptons
247 < It is in particular worth mentioning that the lepton associated to the \W-decay
248 < is correclty matched to the true lepton from the \W-decay in more than 90\% of
249 < the cases even for events with several lepton candidates available to be associated
250 < to the \W-decay. The choice to take the candidate with the leading \pt is therefore
251 < justified.
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 256 | Line 254 | justified.
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 \\
303 < Found $Z \to \mu\mu$     & 233.75 (42.8114 \%)   & 31889.4 (43.8219 \%)  & 577257 (45.5284 \%)   & 2778.81 (15.8282 \%) \\
304 < Found $W \to \mu$        & 57.7986 (24.7267 \%)  & 810.721 (2.54229 \%)  & 2520.69 (0.436668 \%)         & 35.3061 (1.27054 \%) \\
305 < W Lepton Pt cut                  & 44.2533 (76.5646 \%)  & 8.89355 (1.09699 \%)  & 1.84115 (0.0730414 \%)        & 1.683 (4.76688 \%) \\
306 < Passes HLT                       & 43.9977 (99.4225 \%)  & 8.89355 (100 \%)      & 1.84115 (100 \%)      & 1.683 (100 \%) \\
307 < Z mass window    & 40.0462 (91.0188 \%)  & 7.78185 (87.5 \%)     & 1.84115 (100 \%)      & 1.15783 (68.7957 \%) \\ \hline
308 < 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}
# Line 319 | Line 312 | Z mass window    & 40.0462 (91.0188 \%)
312  
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 355 | Line 349 | $3\mu$     &  0 \%  &  23.4 \%  &  0.057
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\\
385 < \hline \hline
386 < \multicolumn{4}{c}{exactly 1 W lepton candidate} \\ \hline
387 < $2e1\mu$   & all & 0     & 1715 \\
388 < $2e1\mu$   & matched Z & -1+/--1 & 0.999+/-0.000583\\
389 < $2e1\mu$   & matched W & -1+/--1 & 1+/-0\\
390 < $2e1\mu$   & 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 < \multicolumn{4}{c}{more than 1 W lepton candidate} \\ \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 >
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 408 | 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 461 | Line 465 | $3\mu$     & matched WZ & -1+/--1 & 0.90
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  
# Line 470 | Line 493 | $3\mu$     & matched WZ & -1+/--1 & 0.90
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 81.1 GeV $< M_Z < $ 101.1 \gev
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}
# Line 479 | Line 502 | $3\mu$     & matched WZ & -1+/--1 & 0.90
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.
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 81.1 GeV $< M_Z < $ 101.1 GeV are shown.
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}

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