| 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 |
|
|
| 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 |
| 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 |
> |
The muons fullfilling all these requirements will be called ``tight'', while global |
| 111 |
> |
muons without requirements on isolation or impact parameter significance are called ``loose''. |
| 112 |
|
|
| 113 |
|
\begin{figure}[p] |
| 114 |
|
\begin{center} |
| 117 |
|
of the requirement on the \W-boson lepton impact parameter |
| 118 |
|
significance. All other criteria but the one on impact parameter |
| 119 |
|
significance are applied. |
| 120 |
< |
% Only events with 81.1 GeV $< M_Z < $ 101.1 \gev |
| 120 |
> |
% Only events with 81 GeV $< M_Z < $ 101 \gev |
| 121 |
|
% are considered. |
| 122 |
|
} |
| 123 |
|
\label{fig:wl_IP_eff} |
| 130 |
|
\caption{Signal significance as a function of requirement on |
| 131 |
|
the \W-boson lepton impact parameter significance. All other criteria but |
| 132 |
|
the requirement on the impact parameter significance are applied. |
| 133 |
< |
% Only events with 81.1 GeV $< M_Z < $ 101.1 \gev are considered. |
| 133 |
> |
% Only events with 81 GeV $< M_Z < $ 101 \gev are considered. |
| 134 |
|
} |
| 135 |
|
\label{fig:wl_IP_SvsCut} |
| 136 |
|
\end{center} |
| 169 |
|
\caption{Efficiency for signal and background as a function |
| 170 |
|
of the cut value on the \W-boson lepton transverse momentum. |
| 171 |
|
All other cuts but the cut on this variable are applied. |
| 172 |
< |
Only events with 81.1 GeV $< M_Z < $ 101.1 \gev |
| 172 |
> |
Only events with 81 GeV $< M_Z < $ 101 \gev |
| 173 |
|
are considered.} |
| 174 |
|
\label{fig:wlpt_cuteff} |
| 175 |
|
\end{center} |
| 181 |
|
\caption{Signal significance as a function of the cut value on |
| 182 |
|
the \W-boson lepton transverse momentum. All other cuts but |
| 183 |
|
the cut on this variable are applied. Only events with |
| 184 |
< |
81.1 GeV $< M_Z < $ 101.1 \gev are considered.} |
| 184 |
> |
81 GeV $< M_Z < $ 101 \gev are considered.} |
| 185 |
|
\label{fig:wlpt_cutS} |
| 186 |
|
\end{center} |
| 187 |
|
\end{figure} |
| 212 |
|
%Figure~\ref{fig:dzmass}. |
| 213 |
|
|
| 214 |
|
After the \Z boson candidate is identified, the remaining leptons in the event |
| 215 |
< |
are required to pass the tight criteria described in~\cite{noteElectronID}. |
| 215 |
> |
are required, for electrons, to pass the tight criteria described in~\cite{noteElectronID} |
| 216 |
> |
or, for muons, all criteria described in section~\ref{sec:leptonId}. |
| 217 |
|
If more than one lepton candidate satisfies the tight requirements, the one with the |
| 218 |
|
highest $p_T$ is associated with \W boson decay. This lepton's $p_T$ is effective |
| 219 |
|
discriminant against \Zbbbar and \Zjets production (see Fig.~\ref{fig:wlpt_cuteff}). |
| 220 |
|
We require the transverse momentum to exceed 20 GeV, as it maximizes |
| 221 |
|
the significance of the \WZ\ signal with respect to background as shown in |
| 222 |
< |
Fig.~\ref{wlpt_cuteff}. |
| 222 |
> |
Fig.~\ref{fig:wlpt_cutS}. |
| 223 |
|
|
| 224 |
|
An additional requirement on the isolation between electron and muon candidates is applied |
| 225 |
|
for the $2\mu 1e$ channel, by demanding the value of $\Delta R$ between the electron |
| 228 |
|
|
| 229 |
|
This requirement allows suppressing the contribution of $\Z \to \mu\mu$ |
| 230 |
|
decays, where one of the two muons radiates a photon which is reconstructed |
| 231 |
< |
as an electron, possibly after conversion. This can be seen as a peak in the dimuon |
| 232 |
< |
invariant mass at around 60 GeV in Fig.~\ref{fig:Z2mu1e_60GeVPeak}. |
| 231 |
> |
as an electron, possibly after conversion. |
| 232 |
> |
% ADD THE PLOT TO JUSTIFY THIS COMMENT |
| 233 |
> |
% This can be seen as a peak in the dimuon |
| 234 |
> |
%invariant mass at around 60 GeV in Fig.~\ref{fig:Z2mu1e_60GeVPeak}. |
| 235 |
|
|
| 236 |
|
The summary of the selection criteria is given in Table~\ref{tab:allcuts}. |
| 237 |
|
|
| 245 |
|
on the third lepton, as leptons from $\tau$ decays are not as energetic as those from |
| 246 |
|
$\W \to \ell \nu$ processes. |
| 247 |
|
|
| 248 |
< |
In Tables~ref\label{tab:wz-matcheffi-Zee} and \label{tab:wz-matcheffi-Zmumu} we |
| 248 |
> |
In Tables~\ref{tab:wz-matcheffi-Zee} and \ref{tab:wz-matcheffi-Zmumu} we |
| 249 |
|
display the fraction of reconstructed \WZ events with correctly-matched leptons. |
| 250 |
|
It can be seen that the lepton associated with the \W boson decay is correctly matched |
| 251 |
|
to the true Monte Carlo lepton from the \W boson decay in more than 90\% of |
| 256 |
|
\begin{table}[p] |
| 257 |
|
\begin{center} |
| 258 |
|
|
| 259 |
< |
|
| 251 |
< |
|
| 252 |
< |
|
| 253 |
< |
\begin{tabular}{lcc|cc|cc|cc|c} \hline \hline |
| 259 |
> |
\begin{tabular}{lcc|cc|cc|cc|} \hline |
| 260 |
|
\multicolumn{9}{c}{ {\bf $3e$ Channel}} \\ \hline \hline |
| 261 |
< |
Step & \WZ & $\epsilon$ & $b\bar{b}\ell\ell$ & $\epsilon$ & $\Z+jets$ & $\epsilon$ & $t\bar{t}+jets$ & $\epsilon$ \\ \hline |
| 262 |
< |
All events & 546 & & 72,700 & & 1,268,000 & & 17,600 & \\ |
| 263 |
< |
Found $\Z \to ee$ & 205 & 38\% & 27,800 & 38\% & 502,300 & 40\% & 2,920 & 17\% \\ |
| 264 |
< |
Found $\W \to e\nu$ & 42.0 & 21\% & 171 & 0.6\% & 309.6 & 0.06\% & 13.8 & 0.5\% \\ |
| 265 |
< |
\W lepton $p_T$ cut & 34.9 & 83\% & 23.7 & 14\% & 86.8 & 28 \% & 8.3 & 60\% \\ |
| 266 |
< |
Passes HLT & 34.7 & 100\% & 23.6 & 99\% & 86.8 &100\% & 8.3 & 100\% \\ |
| 267 |
< |
\Z mass window & 31.6 & 91\% & 17.5 & 74\% & 51.9 &60\% & 3.3 & 39\% \\ \hline |
| 268 |
< |
Overall efficiency & & 5.8\% & & 0.024\% & & 0.0041\% & & 0.019\% \\ |
| 269 |
< |
\hline\hline |
| 261 |
> |
Step & $\WZ \to 3e\nu$ & $ \epsilon$ & $\Z+jets$ & $ \epsilon$ & $t\bar{t}+jets$ & $ \epsilon$ & $b\bar{b}\ell\ell$ & $ \epsilon$\\ \hline |
| 262 |
> |
All events & 185 & & $5.82\cdot 10^6$ & & $8.27\cdot 10^5$ & & $1.44\cdot 10^5$ & \\ |
| 263 |
> |
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\% \\ |
| 264 |
> |
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\% \\ |
| 265 |
> |
Found $\W \to e\nu$ & 37.4 & 50.6\% & 310 & 0.062\% & 13.8 & 0.474\% & 171 & 0.61\% \\ |
| 266 |
> |
\W lepton $p_T$ cut & 32.5 & 86.7\% & 86.8 & 28\% & 8.26 & 59.7\% & 23.4 & 13.7\% \\ |
| 267 |
> |
Passes HLT & 32.3 & 99.6\% & 86.8 & 100\% & 8.26 & 100\% & 23.3 & 99.7\% \\ |
| 268 |
> |
\Z mass window & 29.5 & 91.2\% & 51.9 & 59.8\% & 3.26 & 39.5\% & 17.3 & 74\% \\ |
| 269 |
> |
\hline |
| 270 |
> |
Overall efficiency & & 15.9\% & & 0.00089\% & & 0.00039\% & & 0.012\% \\ |
| 271 |
> |
\hline |
| 272 |
|
|
| 273 |
|
\multicolumn{9}{c}{ {\bf $2e1\mu$ Channel}} \\ \hline \hline |
| 274 |
< |
Step & \WZ & $\epsilon$ & $b\bar{b}\ell\ell$ & $\epsilon$ & $\Z+jets$ & $\epsilon$ & $t\bar{t}+jets$ & $\epsilon$ \\ \hline |
| 275 |
< |
All events & 546 & & 72,770 & & 1,268,000 & & 17,600 & \\ |
| 276 |
< |
Found $\Z \to ee$ & 201 & 38\% & 27,800 & 38\% & 502,300 & 40\% & 2,921 &17\% \\ |
| 277 |
< |
Found $\W \to \mu\nu$ & 47.9 & 23\% & 748 & 2.7\% & 2194 & 0.43\% & 56.8 &1.9\% \\ |
| 278 |
< |
\W lepton $p_T$ cut & 37.1 & 77\% & 9.6 & 1.3\% & 9.6 & 0.4\% & 17.5 &31\% \\ |
| 279 |
< |
Passes HLT & 36.2 & 98\% & 9.3 & 96\% & 8.3 & 87\% & 15.2 & 87 \%) \\ |
| 280 |
< |
\Z mass window & 32.5 & 90\% & 8.2 & 88\% & 7.3 & 88\% & 4.9 & 32\%) \\ \hline |
| 281 |
< |
Overall efficiency & & 6.0\% & & 0.011\% & & 0.00058\% & & 0.028\% \\ |
| 282 |
< |
\hline \hline |
| 274 |
> |
Step & $\WZ \to 2e1\mu\nu$ & $ \epsilon$ & $\Z+jets$ & $ \epsilon$ & $t\bar{t}+jets$ & $ \epsilon$ & $b\bar{t}\ell\ell$ & $ \epsilon$\\ \hline |
| 275 |
> |
All events & 185 & & $5.82\cdot 10^6$ & & $8.27\cdot 10^5$ & & $1.44\cdot 10^5$ & \\ |
| 276 |
> |
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\% \\ |
| 277 |
> |
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\% \\ |
| 278 |
> |
Found $\W \to \mu\nu$ & 42.6 & 66.8\% & $2.19\cdot 10^3$ & 0.44\% & 55.6 & 1.91\% & 748 & 2.69\% \\ |
| 279 |
> |
\W lepton $p_T$ cut & 35.1 & 82.5\% & 9.58 & 0.44\% & 16.4 & 29.5\% & 9.49 & 1.27\% \\ |
| 280 |
> |
Passes HLT & 34.3 & 97.6\% & 8.32 & 86.9\% & 14.1 & 86\% & 9.12 & 96.1\% \\ |
| 281 |
> |
\Z mass window & 30.8 & 89.8\% & 7.31 & 87.9\% & 3.76 & 26.7\% & 8 & 87.8\% \\ |
| 282 |
> |
\hline |
| 283 |
> |
Overall efficiency & & 16.7\% & & 0.00013\% & & 0.00045\% & & 0.0056\% \\ |
| 284 |
> |
\hline |
| 285 |
|
|
| 286 |
|
\multicolumn{9}{c}{ {\bf $2\mu1e$ Channel}} \\ \hline \hline |
| 287 |
< |
Step & \WZ & $\epsilon$ & $b\bar{b}\ell\ell$ & $\epsilon$ & $\Z+jets$ & $\epsilon$ & $t\bar{t}+jets$ & $\epsilon$ \\ \hline |
| 288 |
< |
All events & 546 & & 72,770 & & 1,268,000 & & 17,600 & \\ |
| 289 |
< |
Found $\Z \to \mu\mu$ & 234 &43\%& 31,890 & 44\% & 577,200 & 46\% & 2779 & 16\% \\ |
| 290 |
< |
Found $\W \to e\nu$ & 48.8 &21\%& 214 & 0.67\% & 702 & 0.12\% & 15.1 & 0.54\% \\ |
| 291 |
< |
\W lepton $p_T$ cut & 40.7 &83\%& 50.6 & 24\% & 464.0 & 66\% & 10.3 & 68\% \\ |
| 292 |
< |
$\Delta R(e,\mu)$ cut & 40.6&100\%& 23.3 & 46\% & 93.0 & 20\% & 7.1 & 70\% \\ |
| 293 |
< |
Passes HLT & 39.4 &97\%& 23.2 & 99\% & 88.8 & 95\% & 6.6 & 93\% \\ |
| 294 |
< |
\Z mass window & 35.6 & 90\% & 18.9 & 81\% & 50.3 & 57\% & 2.8 &44\% \\ \hline |
| 295 |
< |
Overall efficiency & &6.5\% & & 0.026\% & & 0.0040\% & & 0.016\% \\ |
| 296 |
< |
\hline \hline |
| 297 |
< |
|
| 287 |
> |
Step & $\WZ \to 2\mu1e$ & $ \epsilon$ & $\Z+jets$ & $ \epsilon$ & $t\bar{t}+jets$ & $ \epsilon$ & $b\bar{b}\ell\ell$ & $ \epsilon$\\ \hline |
| 288 |
> |
All events & 190 & & $5.82\cdot 10^6$ & & $8.27\cdot 10^5$ & & $1.44\cdot 10^5$ & \\ |
| 289 |
> |
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\% \\ |
| 290 |
> |
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\% \\ |
| 291 |
> |
Found $\W \to e\nu$ & 44 & 58.5\% & 702 & 0.12\% & 15.1 & 0.54\% & 213 & 0.67\% \\ |
| 292 |
> |
\W lepton $p_T$ cut & 38.4 & 87.2\% & 464 & 66.2\% & 10.3 & 68\% & 50.5 & 23.7\% \\ |
| 293 |
> |
$\Delta R(e,\mu)$ cut & 38.4 & 99.9\% & 93 & 20\% & 7.15 & 69.6\% & 23.3 & 46\% \\ |
| 294 |
> |
Passes HLT & 37.3 & 97.1\% & 88.8 & 95.5\% & 6.62 & 92.7\% & 23.1 & 99.4\% \\ |
| 295 |
> |
\Z mass window & 33.6 & 90.1\% & 50.3 & 56.6\% & 2.84 & 42.9\% & 18.8 & 81.4\% \\ |
| 296 |
> |
\hline |
| 297 |
> |
Overall efficiency & & 17.7\% & & 0.00086\% & & 0.00034\% & & 0.013\% \\ |
| 298 |
> |
\hline |
| 299 |
> |
%\end{tabular} |
| 300 |
> |
%\begin{tabular}{lcc|cc|cc|cc|} \hline |
| 301 |
|
\multicolumn{9}{c}{ {\bf $3\mu$ Channel}} \\ \hline \hline |
| 302 |
< |
Step & \WZ & $\epsilon$ & ${b\bar{b}\ell\ell}$ & $\epsilon$ & $\Z+jets$ & $\epsilon$ & ${t\bar{t}+jets}$ & $\epsilon$ \\ \hline |
| 303 |
< |
All events & 546 & & 72,770 & & 1,268,000 & & 17,600 & \\ |
| 304 |
< |
Found $Z \to \mu\mu$ & 234 & 43\% & 31,900 & 44\% & 577,000 & 45\% & 2779 & 16 \% \\ |
| 305 |
< |
Found $W \to \mu$ & 58 & 25 \% & 811 & 2.5\% & 2521 & 0.44\% & 35.3 & 1.23 \% \\ |
| 306 |
< |
W Lepton Pt cut & 44.2 & 77 \% & 8.9 & 1.1\% & 1.8 & 0.07\% & 1.7 & 4.8 \% \\ |
| 307 |
< |
Passes HLT & 44.0 & 99\% & 8.9 & 100\% & 1.8 & 100 \% & 1.7 & 100 \% \\ |
| 308 |
< |
Z mass window & 40.0 & 91 \%) & 7.8 & 88\% & 1.8 & 100 \% & 1.2 & 69\% \\ \hline |
| 309 |
< |
Overall efficiency & & 7.3 \% & & 0.011\% & & 0.00015\% & & 0.0065\% \\ |
| 302 |
> |
Step & $\WZ \to 3\mu$ & $ \epsilon$ & $\Z+jets$ & $ \epsilon$ & $t\bar{t}+jets$ & $ \epsilon$ & $b\bar{b}\ell\ell$ & $ \epsilon$\\ \hline |
| 303 |
> |
All events & 189 & & $5.82\cdot 10^6$ & & $8.27\cdot 10^5$ & & $1.44\cdot 10^5$ & \\ |
| 304 |
> |
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\% \\ |
| 305 |
> |
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\% \\ |
| 306 |
> |
Found $\W \to \mu\nu$ & 51.8 & 62\% & $2.52\cdot 10^3$ & 0.44\% & 34.8 & 1.25\% & 810 & 2.54\% \\ |
| 307 |
> |
\W lepton $p_T$ cut & 42.5 & 81.9\% & 1.84 & 0.07\% & 1.16 & 3.33\% & 8.89 & 1.1\% \\ |
| 308 |
> |
Passes HLT & 42.2 & 99.4\% & 1.84 & 100\% & 1.16 & 100\% & 8.89 & 100\% \\ |
| 309 |
> |
\Z mass window & 38.5 & 91.1\% & 1.84 & 100\% & 1.16 & 100\% & 7.78 & 87.5\% \\ |
| 310 |
> |
\hline |
| 311 |
> |
Overall efficiency & & 20.3\% & & 0.000032\% & & 0.00014\% & & 0.0054\% \\ |
| 312 |
|
\hline |
| 313 |
|
\end{tabular} |
| 314 |
|
|
| 300 |
– |
|
| 315 |
|
\caption{Expected number of signal and background events passing the different |
| 316 |
|
selections steps together with the efficiency of each requirement and total efficiency of |
| 317 |
|
selection criteria in the \WZ, \Zbbbar, \Zjets and \ttjets samples for an integrated luminosity |
| 331 |
|
& $\tau \nu \to \mu \nu \nu $ |
| 332 |
|
& $\tau \nu \to {\rm hadrons~} \nu$ |
| 333 |
|
\\ \hline |
| 334 |
< |
$3e$ & 17.4 \% & 0.0319 \% & 6.42 \% & 0 \% & 0.162 \% \\ |
| 335 |
< |
$2e1\mu$ & 0 \% & 18.6 \% & 0 \% & 5.53 \% & 0.0485 \% \\ |
| 336 |
< |
$2\mu1e$ & 0 \% & 0 \% & 0 \% & 0 \% & 0 \% \\ |
| 337 |
< |
$3\mu$ & 0 \% & 0 \% & 0 \% & 0 \% & 0 \% \\ |
| 334 |
> |
$3e$ & 17.4\% & 0.0319\% & 6.42\% & 0\% & 0.162\% \\ |
| 335 |
> |
$2e1\mu$ & 0\% & 18.6\% & 0\% & 5.53\% & 0.0485\% \\ |
| 336 |
> |
$2\mu1e$ & 0\% & 0\% & 0\% & 0\% & 0\% \\ |
| 337 |
> |
$3\mu$ & 0\% & 0\% & 0\% & 0\% & 0\% \\ |
| 338 |
|
\hline \hline |
| 339 |
|
|
| 340 |
|
& \multicolumn{5}{c}{$\Z \to \mu\mu$ and \W decay modes below} \\ |
| 344 |
|
& $\tau\nu \to \mu\nu\nu$ |
| 345 |
|
& $\tau\nu \to {\rm hadrons~}\nu$ |
| 346 |
|
\\ \hline |
| 347 |
< |
$3e$ & 0 \% & 0 \% & 0 \% & 0 \% & 0 \% \\ |
| 348 |
< |
$2e1\mu$ & 0.0104 \% & 0 \% & 0 \% & 0 \% & 0 \% \\ |
| 349 |
< |
$2\mu1e$ & 19.6 \% & 0.0208 \% & 5.56 \% & 0 \% & 0.18 \% \\ |
| 350 |
< |
$3\mu$ & 0 \% & 23.4 \% & 0.0573 \% & 6.77 \% & 0.0164 \% \\ |
| 347 |
> |
$3e$ & 0\% & 0\% & 0\% & 0\% & 0\% \\ |
| 348 |
> |
$2e1\mu$ & 0.0104\% & 0\% & 0\% & 0\% & 0\% \\ |
| 349 |
> |
$2\mu1e$ & 19.6\% & 0.0208\% & 5.56\% & 0\% & 0.18\% \\ |
| 350 |
> |
$3\mu$ & 0\% & 23.4\% & 0.0573\% & 6.77\% & 0.0164\% \\ |
| 351 |
|
\hline \hline |
| 352 |
|
\end{tabular} |
| 353 |
|
\end{center} |
| 470 |
|
\end{table} |
| 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 |
|
%\subsection{Signal extraction} |
| 492 |
|
%\input D0Matrix |
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\input zjetbackground |
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\begin{figure}[bt] |
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|
\begin{center} |
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|
\scalebox{0.8}{\includegraphics{figs/met_by_channel.eps}} |
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< |
\caption{Missing transverse mass for the four signal categories. |
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> |
\caption{Missing transverse energy for the four signal categories. |
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The distributions show the number of expected events |
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< |
for $1 fb^{-1}$. Only events with 81.1 GeV $< M_Z < $ 101.1 \gev |
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> |
for $1 fb^{-1}$. Only events with 81 GeV $< M_Z < $ 101 \gev |
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|
are shown. All selection cuts are applied.} |
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\label{fig:met} |
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|
\end{center} |
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\scalebox{0.8}{\includegraphics{figs/mtw_by_channel.eps}} |
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\caption{\W transverse mass for the four signal categories. |
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The distributions show the number of expected events |
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< |
for $1 fb^{-1}$. Only events with 81.1 GeV $< M_Z < $ 101.1 GeV are shown. |
| 516 |
> |
for $1 fb^{-1}$. Only events with 81 GeV $< M_Z < $ 101 GeV are shown. |
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|
All selection cuts are applied.} |
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\label{fig:mtw} |
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|
\end{center} |
