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Revision 1.18 by ymaravin, Fri Jun 27 23:28:08 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 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 206 | Line 209 | secondary \Z boson veto helps to suppres
209   %Figure~\ref{fig:dzmass}.
210  
211   After the \Z boson candidate is identified, the remaining leptons in the event
212 < are required to pass the tight criteria described in~\cite{noteElectronID}.
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{wlpt_cuteff}.
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
# Line 236 | Line 240 | decays. However, this contribution is su
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\label{tab:wz-matcheffi-Zee} and \label{tab:wz-matcheffi-Zmumu} we
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
# Line 247 | Line 251 | therefore, justified.
251   \begin{table}[p]
252    \begin{center}
253  
254 <
251 <
252 <
253 < \begin{tabular}{lcc|cc|cc|cc|c} \hline \hline
254 > \begin{tabular}{lcc|cc|cc|cc|} \hline
255   \multicolumn{9}{c}{ {\bf $3e$ Channel}} \\ \hline  \hline
256 < Step                                 & \WZ  & $\epsilon$ & $b\bar{b}\ell\ell$  & $\epsilon$ & $\Z+jets$  & $\epsilon$ & $t\bar{t}+jets$  & $\epsilon$ \\ \hline
257 < All events                       & 546   &                    & 72,700 &                     & 1,268,000       &                       & 17,600     &               \\
258 < Found $\Z \to ee$         & 205   & 38\%         & 27,800 & 38\%            & 502,300          & 40\%            & 2,920        & 17\%    \\
259 < Found $\W \to e\nu$    & 42.0  & 21\%         & 171       & 0.6\%           & 309.6               & 0.06\%        & 13.8           & 0.5\%   \\
260 < \W lepton $p_T$ cut    & 34.9  & 83\%          & 23.7     & 14\%            & 86.8                  & 28 \%          &   8.3            & 60\%   \\
261 < Passes HLT                  & 34.7  & 100\%        & 23.6     & 99\%            & 86.8                  &100\%         &   8.3            & 100\%  \\
262 < \Z mass window           & 31.6  & 91\%          & 17.5     & 74\%            & 51.9                  &60\%           &    3.3            & 39\%    \\ \hline
263 < Overall efficiency        &           &  5.8\%        &              &   0.024\%    &                            & 0.0041\%  &                     & 0.019\% \\
264 < \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
267  
268   \multicolumn{9}{c}{ {\bf $2e1\mu$ Channel}} \\ \hline  \hline
269 < Step   & \WZ  & $\epsilon$ & $b\bar{b}\ell\ell$ & $\epsilon$ & $\Z+jets$  & $\epsilon$ & $t\bar{t}+jets$ & $\epsilon$  \\ \hline
270 < All events                        & 546  &             & 72,770 &                 & 1,268,000       &                    & 17,600            &             \\
271 < Found $\Z \to ee$          & 201  & 38\%  & 27,800  & 38\%      &  502,300          &  40\%     &     2,921          &17\% \\
272 < Found $\W \to \mu\nu$ & 47.9 & 23\%  & 748       & 2.7\%      &  2194         &  0.43\%  &      56.8          &1.9\% \\
273 < \W lepton $p_T$ cut      & 37.1 & 77\%  & 9.6        & 1.3\%      &   9.6                  &  0.4\%         &      17.5         &31\% \\
274 < Passes HLT                    & 36.2 & 98\%  & 9.3        & 96\%       &   8.3                  &  87\%    &     15.2   & 87 \%) \\
275 < \Z mass window             & 32.5 & 90\%  & 8.2        &  88\%      &    7.3                 &  88\%            &       4.9         & 32\%) \\ \hline
276 < Overall efficiency          &          & 6.0\% &               & 0.011\% &                           &  0.00058\% &                      &     0.028\% \\
277 < \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
280  
281   \multicolumn{9}{c}{ {\bf $2\mu1e$ Channel}} \\ \hline  \hline
282 < Step   & \WZ   & $\epsilon$ & $b\bar{b}\ell\ell$   & $\epsilon$ & $\Z+jets$   & $\epsilon$ & $t\bar{t}+jets$  & $\epsilon$ \\ \hline
283 < All events       & 546  &   & 72,770   &    & 1,268,000 &    & 17,600 &  \\
284 < Found $\Z \to \mu\mu$     & 234  &43\%&      31,890 & 44\% & 577,200 & 46\%   & 2779 & 16\% \\
285 < Found $\W \to e\nu$          & 48.8 &21\%&    214        & 0.67\%   & 702 & 0.12\%         & 15.1 & 0.54\% \\
286 < \W lepton $p_T$ cut          & 40.7 &83\%&      50.6      & 24\%      & 464.0 & 66\%      & 10.3 & 68\% \\
287 < $\Delta R(e,\mu)$ cut       & 40.6&100\%&      23.3     & 46\%     & 93.0 & 20\%         & 7.1 & 70\%  \\
288 < Passes HLT                       & 39.4 &97\%&        23.2     & 99\%      & 88.8 & 95\%        & 6.6  & 93\%  \\
289 < \Z mass window                & 35.6 & 90\% &          18.9 & 81\%      & 50.3 & 57\%       & 2.8   &44\%  \\ \hline
290 < Overall efficiency              &           &6.5\%  &                  & 0.026\% &           & 0.0040\%  &          & 0.016\% \\
291 < \hline \hline
292 <
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   & $\epsilon$ & ${b\bar{b}\ell\ell}$   & $\epsilon$ & $\Z+jets$   & $\epsilon$ & ${t\bar{t}+jets}$  & $\epsilon$ \\ \hline
298 < All events       & 546 &   & 72,770  &      & 1,268,000  &   & 17,600 &  \\
299 < Found $Z \to \mu\mu$        & 234     & 43\%   & 31,900 & 44\%       & 577,000 & 45\%          & 2779  & 16 \% \\
300 < Found $W \to \mu$             & 58        & 25 \%  & 811      & 2.5\%      & 2521       & 0.44\%       & 35.3   & 1.23 \% \\
301 < W Lepton Pt cut                   & 44.2    & 77 \% & 8.9         & 1.1\%      & 1.8          & 0.07\%        & 1.7     & 4.8 \% \\
302 < Passes HLT                         & 44.0    & 99\%  & 8.9          & 100\%    & 1.8         & 100 \%        & 1.7     & 100 \% \\
303 < Z mass window                   & 40.0    & 91 \%)  & 7.8        & 88\%      & 1.8          & 100 \%        & 1.2     & 69\% \\ \hline
304 < Overall efficiency               &             & 7.3 \% &                & 0.011\% &                & 0.00015\% &            & 0.0065\% \\
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  
300
310   \caption{Expected number of signal and background events passing the different
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
# Line 317 | Line 326 | Reconstruction channel  &  $e \nu$
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 \% \\
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} \\
# Line 330 | Line 339 | $3\mu$     &  0 \%  &  0 \%  &  0 \%  &
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}
# Line 461 | Line 470 | $3\mu$     & matched \WZ & 0 & 91$\pm$4\
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  
# Line 468 | Line 496 | $3\mu$     & matched \WZ & 0 & 91$\pm$4\
496   \begin{figure}[bt]
497    \begin{center}
498    \scalebox{0.8}{\includegraphics{figs/met_by_channel.eps}}
499 <  \caption{Missing transverse mass for the four signal categories.
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 81.1 GeV $< M_Z < $ 101.1 \gev
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}
# Line 479 | Line 507 | $3\mu$     & matched \WZ & 0 & 91$\pm$4\
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.
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 81.1 GeV $< M_Z < $ 101.1 GeV are shown.
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}

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