| 1 |
benhoob |
1.1 |
\clearpage
|
| 2 |
|
|
|
| 3 |
|
|
\section{Systematic Uncertainties in Signal Acceptance}
|
| 4 |
|
|
|
| 5 |
|
|
In this section we discuss systematic uncertainties in the signal acceptance. These efficiency
|
| 6 |
|
|
uncertainties are relevant for the interpretations in the \wzmet\ and the GMSB models, which
|
| 7 |
|
|
are combined with the results of the trilepton and quadlepton analysis, respectively, in AN-2012/351.
|
| 8 |
|
|
|
| 9 |
|
|
\begin{table}[htb]
|
| 10 |
|
|
\begin{center}
|
| 11 |
|
|
\footnotesize
|
| 12 |
|
|
\caption{\label{tab:syst} Summary of uncertainties in the signal efficiency. }
|
| 13 |
|
|
\begin{tabular}{l|c|l}
|
| 14 |
|
|
\hline
|
| 15 |
|
|
\hline
|
| 16 |
|
|
Source & Value (\%) & Method \\
|
| 17 |
|
|
\hline
|
| 18 |
|
|
Luminosity & 4.4 & official CMS value \\
|
| 19 |
|
|
Trigger efficiency & 3 & efficiency measurements documented in Sec. 4, Table 9 of AN-2012/248 \\
|
| 20 |
|
|
Lepton ID/isolation & 2 (per lepton) & Z tag-and-probe measurements in AN-2012/257 \\
|
| 21 |
|
|
B-veto & 6 & dedicated measurement in AN-2012/248 Sec. 7.6 \\
|
| 22 |
|
|
Z mass window requirement & 3 & see text and Table~\ref{tab:mllsyst} \\
|
| 23 |
|
|
Jet selection, dijet mass, \MET & assessed at each model point & official JetMet POG recipe \\
|
| 24 |
|
|
\hline
|
| 25 |
|
|
\hline
|
| 26 |
|
|
\end{tabular}
|
| 27 |
|
|
\end{center}
|
| 28 |
|
|
\end{table}
|
| 29 |
|
|
|
| 30 |
|
|
A summary of the efficiency uncertainties is presented in Table~\ref{tab:syst}.
|
| 31 |
|
|
The CMS uncertainty in the luminosity is 4.4\%. The trigger efficiency is measured in AN-2102/248 with an uncertainty of 3\%.
|
| 32 |
|
|
The lepton identification and isolation requirements are measured in data and MC and found to be consistent within 2\%, for
|
| 33 |
|
|
the \pt\ $>$ 20 GeV region relevant for this analysis, in AN-2012/257. The impact of the b-veto on the signal acceptance
|
| 34 |
|
|
is quantified with a dedicated measurement performed in Sec. 7.6 of AN-2012/248. The uncertainty in the selection of dilepton
|
| 35 |
|
|
events satisfying the Z mass window requirement 81--101 GeV is performed as follows. In both data and MC, the Z mass window
|
| 36 |
|
|
in the inclusive preselection region (Z and at least 2 jets) is loosened to 60--120 GeV.
|
| 37 |
|
|
The efficiency of the events in the loose window to satisfy the analysis dilepton mass selection
|
| 38 |
|
|
of 81--101 GeV is compared in data and MC, and found to be consistent within 3\% for both ee and $\mu\mu$ channels
|
| 39 |
|
|
(see Table~\ref{tab:mllsyst}), and a corresponding uncertainty on the signal efficiency is assessed.
|
| 40 |
|
|
|
| 41 |
|
|
The above uncertainties are the same for all SUSY model points. However the impact of the jet energy scale uncertainty, which
|
| 42 |
|
|
affects the selection efficiencies for all jets and \MET\ objects, varies significantly across the model parameter space and
|
| 43 |
|
|
is assessed separately at each point. The official JetMet POG recipe is used for this purpose. Each jet is assigned an uncertainty
|
| 44 |
|
|
based on its \pt\ and $\eta$. The jet energy is varied by this uncertainty, which is propagated to the efficiencies for the jet selection,
|
| 45 |
|
|
dijet mass selection and \MET\ selection. In addition, for the \MET, a 10\% uncertainty on the unclustered energy is included.
|
| 46 |
|
|
The \MET\ variation alters the shape of the signal \MET\ distribution and causes a bin-to-bin migration of events, which is
|
| 47 |
|
|
included in the limit setting procedure performed with LandS.
|
| 48 |
|
|
|
| 49 |
|
|
\begin{table}[htb]
|
| 50 |
|
|
\begin{center}
|
| 51 |
|
|
\footnotesize
|
| 52 |
|
|
\caption{\label{tab:mllsyst} Summary of the dilepton mass selection efficiency uncertainties. Loose and tight refer to dilepton
|
| 53 |
|
|
mass windows of 60--120 GeV and 81-101 GeV, respectively.}
|
| 54 |
|
|
\begin{tabular}{l|c|c}
|
| 55 |
|
|
\hline
|
| 56 |
|
|
\hline
|
| 57 |
|
|
& ee & $\mu\mu$ \\
|
| 58 |
|
|
\hline
|
| 59 |
|
|
MC loose & 200694.0 & 285462.5 \\
|
| 60 |
|
|
MC tight & 183326.2 & 260960.0 \\
|
| 61 |
|
|
MC tight/loose & 0.913 $\pm$ 0.005 & 0.914 $\pm$ 0.004 \\
|
| 62 |
|
|
\hline
|
| 63 |
|
|
data loose & 209540 & 263747 \\
|
| 64 |
|
|
data tight & 185555 & 234132 \\
|
| 65 |
|
|
data tight/loose & 0.886 $\pm$ 0.003 & 0.888 $\pm$ 0.003 \\
|
| 66 |
|
|
\hline
|
| 67 |
|
|
\hline
|
| 68 |
|
|
\end{tabular}
|
| 69 |
|
|
\end{center}
|
| 70 |
|
|
\end{table}
|
