1 |
benhoob |
1.1 |
|
2 |
fkw |
1.5 |
This analysis uses several different control regions in addition to the signal regions.
|
3 |
|
|
All of these different regions are defined in this section.
|
4 |
vimartin |
1.7 |
%Figure~\ref{fig:venndiagram} illustrates the relationship between these regions.
|
5 |
benhoob |
1.1 |
|
6 |
vimartin |
1.7 |
\subsection{Single Lepton Selection}
|
7 |
|
|
|
8 |
|
|
[UPDATE SELECTION]
|
9 |
fkw |
1.5 |
|
10 |
vimartin |
1.10 |
The single lepton preselection sample is based on the following criteria, starting from the requirements described
|
11 |
|
|
on \url{https://twiki.cern.ch/twiki/bin/viewauth/CMS/SUSYstop#SINGLE_LEPTON_CHANNEL}
|
12 |
benhoob |
1.1 |
\begin{itemize}
|
13 |
vimartin |
1.2 |
\item satisfy the trigger requirement (see
|
14 |
claudioc |
1.9 |
Table.~\ref{tab:DatasetsData}).
|
15 |
|
|
Note that the analysis triggers are inclusive single lepton triggers.
|
16 |
|
|
Dilepton triggers are used only for the dilepton control region.
|
17 |
vimartin |
1.2 |
\item select events with one high \pt\ electron or muon, requiring
|
18 |
|
|
\begin{itemize}
|
19 |
vimartin |
1.10 |
\item $\pt>30~\GeVc$ and $|\eta|<1.4442 (2.4)$ for electrons (muons)
|
20 |
|
|
\item muon ID criteria is based on the 2012 POG recommended tight working point
|
21 |
|
|
\item electron ID critera is based on the 2012 POG recommended medium working point
|
22 |
|
|
\item PF-based isolation ($\Delta R < 0.3$, $\Delta\beta$ corrected) relative $<$ 0.15 and absolute $<$ 5~GeV
|
23 |
|
|
\item $|\pt(\rm{PF}_{lep}) - \pt(\rm{RECO}_{lep})| < 10~\GeV$
|
24 |
|
|
\item $E/p_{in} < 4$ (electrons only)
|
25 |
vimartin |
1.2 |
\end{itemize}
|
26 |
|
|
\item require at least 4 PF jets in the event with $\pt>30~\GeV$
|
27 |
vimartin |
1.7 |
within $|\eta|<2.5$ out of which at least 1 satisfies the CSV
|
28 |
|
|
medium working point b-tagging requirement
|
29 |
vimartin |
1.2 |
\item require moderate $\met>50~\GeV$
|
30 |
benhoob |
1.1 |
\end{itemize}
|
31 |
|
|
|
32 |
vimartin |
1.12 |
%Table~\ref{tab:preselectionyield} shows the yields in data and MC without any corrections for this preselection region.
|
33 |
fkw |
1.6 |
|
34 |
vimartin |
1.12 |
%\begin{table}[!h]
|
35 |
|
|
%\begin{center}
|
36 |
|
|
%\begin{tabular}{c|c}
|
37 |
|
|
%\hline
|
38 |
|
|
%\hline
|
39 |
|
|
%\end{tabular}
|
40 |
|
|
%\caption{ Raw Data and MC predictions without any corrections are shown after preselection. \label{tab:preselectionyield}}
|
41 |
|
|
%\end{center}
|
42 |
|
|
%\end{table}
|
43 |
fkw |
1.6 |
|
44 |
vimartin |
1.7 |
\subsection{Signal Region Selection}
|
45 |
|
|
|
46 |
vimartin |
1.8 |
[MOTIVATIONAL BLURB ON MET AND MT, \\
|
47 |
|
|
CAN ADD SIGNAL VS. TTBAR MC PLOT \\
|
48 |
|
|
ADD SIGNAL YIELDS FOR AVAILABLE POINTS, \\
|
49 |
|
|
DISCUSS CHOICE SIG REGIONS]
|
50 |
|
|
|
51 |
vimartin |
1.7 |
The signal regions (SRs) are selected to improve the sensitivity for the
|
52 |
|
|
single lepton requirements and cover a range of scalar top
|
53 |
|
|
scenarios. The \mt\ and \met\ variables are used to define the signal
|
54 |
|
|
regions and the requirements are listed in Table~\ref{tab:srdef}.
|
55 |
|
|
|
56 |
fkw |
1.6 |
\begin{table}[!h]
|
57 |
|
|
\begin{center}
|
58 |
vimartin |
1.7 |
\begin{tabular}{l|c|c}
|
59 |
fkw |
1.6 |
\hline
|
60 |
vimartin |
1.7 |
Signal Region & Minimum \mt\ [GeV] & Minimum \met\ [GeV] \\
|
61 |
fkw |
1.6 |
\hline
|
62 |
|
|
\hline
|
63 |
vimartin |
1.7 |
SRA & 150 & 100 \\
|
64 |
|
|
SRB & 120 & 150 \\
|
65 |
|
|
SRC & 120 & 200 \\
|
66 |
|
|
SRD & 120 & 250 \\
|
67 |
|
|
SRE & 120 & 300 \\
|
68 |
fkw |
1.6 |
\hline
|
69 |
|
|
\end{tabular}
|
70 |
vimartin |
1.7 |
\caption{ Signal region definitions based on \mt\ and \met\
|
71 |
|
|
requirements. These requirements are applied in addition to the
|
72 |
|
|
baseline single lepton selection.
|
73 |
|
|
\label{tab:srdef}}
|
74 |
fkw |
1.6 |
\end{center}
|
75 |
|
|
\end{table}
|
76 |
|
|
|
77 |
vimartin |
1.7 |
Table~\ref{tab:srrawmcyields} shows the expected number of SM
|
78 |
|
|
background yields for the SRs. A few stop signal yields for four
|
79 |
|
|
values of the parameters are also shown for comparison. The signal
|
80 |
|
|
regions with looser requirements are sensitive to lower stop masses
|
81 |
|
|
M(\sctop), while those with tighter requirements are more sensitive to
|
82 |
|
|
higher M(\sctop).
|
83 |
|
|
|
84 |
fkw |
1.6 |
\begin{table}[!h]
|
85 |
|
|
\begin{center}
|
86 |
vimartin |
1.10 |
\begin{tabular}{l||c|c|c|c|c}
|
87 |
fkw |
1.6 |
\hline
|
88 |
vimartin |
1.10 |
Sample & SRA & SRB & SRC & SRD & SRE\\
|
89 |
fkw |
1.6 |
\hline
|
90 |
|
|
\hline
|
91 |
vimartin |
1.13 |
\ttdl\ & $619 \pm 9$& $366 \pm 7$& $127 \pm 4$& $44 \pm 2$& $17 \pm 1$ \\
|
92 |
|
|
\ttsl\ \& single top (1\Lep) & $95 \pm 3$& $67 \pm 3$& $15 \pm 1$& $6 \pm 1$& $2 \pm 1$ \\
|
93 |
|
|
\wjets\ & $29 \pm 2$& $15 \pm 2$& $6 \pm 1$& $3 \pm 1$& $1 \pm 0$ \\
|
94 |
|
|
Rare & $59 \pm 3$& $38 \pm 3$& $16 \pm 2$& $8 \pm 1$& $4 \pm 1$ \\
|
95 |
fkw |
1.6 |
\hline
|
96 |
vimartin |
1.13 |
Total & $802 \pm 10$& $486 \pm 8$& $164 \pm 5$& $62 \pm 3$& $23 \pm 2$ \\
|
97 |
fkw |
1.6 |
\hline
|
98 |
|
|
\end{tabular}
|
99 |
vimartin |
1.7 |
\caption{ Expected SM background contributions, including both muon
|
100 |
claudioc |
1.9 |
and electron channels. This is ``dead reckoning'' MC with no
|
101 |
|
|
correction.
|
102 |
|
|
It is meant only as a general guide. The uncertainties are statistical only. ADD
|
103 |
vimartin |
1.7 |
SIGNAL POINTS.
|
104 |
|
|
\label{tab:srrawmcyields}}
|
105 |
fkw |
1.6 |
\end{center}
|
106 |
|
|
\end{table}
|
107 |
|
|
|
108 |
vimartin |
1.8 |
\subsection{Control Region Selection}
|
109 |
fkw |
1.5 |
|
110 |
vimartin |
1.8 |
[1 PARAGRAPH BLURB RELATING BACKGROUNDS (IN TABLE FROM PREVIOUS SECTION)
|
111 |
|
|
TO INTRODUCE CONTROL REGIONS]
|
112 |
fkw |
1.5 |
|
113 |
vimartin |
1.7 |
Control regions (CRs) are used to validate the background estimation
|
114 |
|
|
procedure and derive systematic uncertainties for some
|
115 |
|
|
contributions. The CRs are selected to have similar
|
116 |
|
|
kinematics to the SRs, but have a different requirement in terms of
|
117 |
|
|
number of b-tags and number of leptons, thus enhancing them in
|
118 |
|
|
different SM contributions. The four CRs used in this analysis are
|
119 |
|
|
summarized in Table~\ref{tab:crdef}.
|
120 |
fkw |
1.5 |
|
121 |
vimartin |
1.7 |
\begin{table}
|
122 |
fkw |
1.6 |
\begin{center}
|
123 |
vimartin |
1.7 |
{\small
|
124 |
|
|
\begin{tabular}{l|c|c|c}
|
125 |
fkw |
1.6 |
\hline
|
126 |
vimartin |
1.7 |
Selection & \multirow{2}{*}{exactly 1 lepton} & \multirow{2}{*}{exactly 2
|
127 |
|
|
leptons} & \multirow{2}{*}{1 lepton + isolated
|
128 |
|
|
track}\\
|
129 |
|
|
Criteria & & & \\
|
130 |
|
|
\hline
|
131 |
|
|
\hline
|
132 |
|
|
\multirow{4}{*}{0 b-tags}
|
133 |
|
|
& CR1) W+Jets dominated:
|
134 |
|
|
& CR2) apply \Z-mass constraint
|
135 |
|
|
& CR3) not used \\
|
136 |
|
|
&
|
137 |
|
|
& $\rightarrow$ Z+Jets dominated: Validate
|
138 |
|
|
& \\
|
139 |
|
|
& Validate W+Jets \mt\ tail
|
140 |
|
|
& \ttsl\ \mt\ tail comparing
|
141 |
|
|
& \\
|
142 |
|
|
&
|
143 |
|
|
& data vs. MC ``pseudo-\mt ''
|
144 |
|
|
& \\
|
145 |
|
|
\hline
|
146 |
|
|
\multirow{4}{*}{$\ge$ 1 b-tags}
|
147 |
|
|
&
|
148 |
|
|
& CR4) Apply \Z-mass veto
|
149 |
|
|
& CR5) \ttdl, \ttlt\ and \\
|
150 |
|
|
& SIGNAL
|
151 |
|
|
& $\rightarrow$ \ttdl\ dominated: Validate
|
152 |
|
|
& \ttlf\ dominated: Validate \\
|
153 |
|
|
& REGION
|
154 |
|
|
& ``physics'' modelling of \ttdl\
|
155 |
|
|
& \Tau\ and fake lepton modeling/\\
|
156 |
|
|
&
|
157 |
|
|
&
|
158 |
|
|
& detector effects in \ttdl\ \\
|
159 |
fkw |
1.6 |
\hline
|
160 |
|
|
\end{tabular}
|
161 |
vimartin |
1.7 |
}
|
162 |
|
|
\caption{Summary of signal and control regions.
|
163 |
|
|
\label{tab:crdef}%\protect
|
164 |
|
|
}
|
165 |
fkw |
1.6 |
\end{center}
|
166 |
|
|
\end{table}
|
167 |
fkw |
1.5 |
|
168 |
vimartin |
1.7 |
|
169 |
|
|
\subsection{MC Corrections}
|
170 |
|
|
|
171 |
|
|
[UPDATE SECTION]
|
172 |
|
|
|
173 |
|
|
\subsubsection{Corrections to Jets and \met}
|
174 |
benhoob |
1.1 |
|
175 |
vimartin |
1.8 |
[UPDATE, ADD FEW MORE DETAILS ON WHAT IS DONE HERE]
|
176 |
|
|
|
177 |
vimartin |
1.2 |
The official recommendations from the Jet/MET group are used for
|
178 |
|
|
the data and MC samples. In particular, the jet
|
179 |
|
|
energy corrections (JEC) are updated using the official recipe.
|
180 |
|
|
L1FastL2L3Residual (L1FastL2L3) corrections are applied for data (MC),
|
181 |
|
|
based on the global tags GR\_R\_42\_V23 (DESIGN42\_V17) for
|
182 |
|
|
data (MC). In addition, these jet energy corrections are propagated to
|
183 |
|
|
the \met\ calculation, following the official prescription for
|
184 |
vimartin |
1.7 |
deriving the Type I corrections.
|
185 |
|
|
|
186 |
|
|
Events with anomalous ``rho'' pile-up corrections are excluded from the sample since these
|
187 |
vimartin |
1.2 |
correspond to events with unphysically large \met\ and \mt\ tail
|
188 |
vimartin |
1.7 |
signal region. In addition, the recommended MET filters are applied.
|
189 |
vimartin |
1.2 |
|
190 |
benhoob |
1.3 |
|
191 |
vimartin |
1.7 |
\subsubsection{Branching Fraction Correction}
|
192 |
vimartin |
1.2 |
|
193 |
|
|
The leptonic branching fraction used in some of the \ttbar\ MC samples
|
194 |
benhoob |
1.3 |
differs from the value listed in the PDG $(10.80 \pm 0.09)\%$.
|
195 |
vimartin |
1.2 |
Table.~\ref{tab:wlepbf} summarizes the branching fractions used in
|
196 |
|
|
the generation of the various \ttbar\ MC samples.
|
197 |
|
|
For \ttbar\ samples with the incorrect leptonic branching fraction, event
|
198 |
|
|
weights are applied based on the number of true leptons and the ratio
|
199 |
|
|
of the corrected and incorrect branching fractions.
|
200 |
|
|
|
201 |
|
|
\begin{table}[!h]
|
202 |
|
|
\begin{center}
|
203 |
|
|
\begin{tabular}{c|c}
|
204 |
|
|
\hline
|
205 |
|
|
\ttbar\ Sample - Event Generator & Leptonic Branching Fraction\\
|
206 |
|
|
\hline
|
207 |
|
|
\hline
|
208 |
|
|
Madgraph & 0.111\\
|
209 |
|
|
MC@NLO & 0.111\\
|
210 |
|
|
Pythia & 0.108\\
|
211 |
|
|
Powheg & 0.108\\
|
212 |
|
|
\hline
|
213 |
|
|
\end{tabular}
|
214 |
|
|
\caption{Leptonic branching fractions for the various \ttbar\ samples
|
215 |
|
|
used in the analysis. The primary \ttbar\ MC sample produced with
|
216 |
|
|
Madgraph has a branching fraction that is almost $3\%$ higher than
|
217 |
|
|
the PDG value. \label{tab:wlepbf}}
|
218 |
|
|
\end{center}
|
219 |
|
|
\end{table}
|
220 |
|
|
|
221 |
vimartin |
1.7 |
|
222 |
benhoob |
1.11 |
\subsubsection{Lepton Selection Efficiency Measurements}
|
223 |
vimartin |
1.7 |
|
224 |
benhoob |
1.11 |
[TO BE UDPATED WITH T\&P STUDIES ON ID,ISO EFFICIENCIES]
|
225 |
vimartin |
1.7 |
|
226 |
benhoob |
1.11 |
|
227 |
|
|
\subsubsection{Trigger Efficiency Measurements}
|
228 |
|
|
|
229 |
|
|
In this section we measure the efficiencies of the single lepton triggers, HLT\_IsoMu24(\_eta2p1) for muons and HLT\_Ele27\_WP80 for electrons, using a tag-and-probe
|
230 |
|
|
approach. The tag is required to pass the full offline analysis selection and have \pt\ $>$ 30 GeV, $|\eta|<2.1$, and be matched to the single
|
231 |
|
|
lepton trigger. The probe is also required to pass the full offline analysis selection and have $|\eta|<2.1$, but the \pt\ requirement is relaxed to 20 GeV
|
232 |
|
|
in order to measure the \pt\ turn-on curve. The tag-probe pair is required to have opposite-sign and an invariant mass in the range 76--106 GeV.
|
233 |
|
|
The measured trigger efficiencies are displayed in Fig.~\ref{fig:trigeff} and summarized in Table~\ref{tab:mutriggeff} (muons) and Table~\ref{tab:eltriggeff} (electrons).
|
234 |
|
|
These trigger efficiencies will be applied to the MC when used to predict data yields selected by single lepton triggers. [THESE TRIGGER EFFICIENCIES TO BE APPLIED TO MC]
|
235 |
|
|
|
236 |
|
|
|
237 |
|
|
\begin{figure}[!ht]
|
238 |
|
|
\begin{center}
|
239 |
|
|
\begin{tabular}{cc}
|
240 |
|
|
\includegraphics[width=0.4\textwidth]{plots/mutrig_pt_etabins.pdf} &
|
241 |
|
|
\includegraphics[width=0.4\textwidth]{plots/eltrig_pt_etabins.pdf} \\
|
242 |
|
|
\end{tabular}
|
243 |
|
|
\caption{\label{fig:trigeff}
|
244 |
|
|
Efficiency for the single muon trigger HLT\_IsoMu24(\_eta2p1) (left) and single electron trigger HLT\_Ele27\_WP80 (right) as a function of lepton \pt,
|
245 |
|
|
for several bins in lepton $|\eta|$.
|
246 |
|
|
}
|
247 |
|
|
\end{center}
|
248 |
|
|
\end{figure}
|
249 |
|
|
|
250 |
|
|
\clearpage
|
251 |
|
|
|
252 |
|
|
\begin{table}[htb]
|
253 |
|
|
\begin{center}
|
254 |
|
|
\footnotesize
|
255 |
|
|
\caption{\label{tab:mutriggeff}
|
256 |
|
|
Summary of the single muon trigger efficiency HLT\_IsoMu24(\_eta2p1). Uncertainties are statistical.}
|
257 |
|
|
\begin{tabular}{c|c|c|c}
|
258 |
|
|
|
259 |
|
|
\hline
|
260 |
|
|
\hline
|
261 |
|
|
\pt\ range [GeV] & $|\eta|<0.8$ & $0.8<|\eta|<1.5$ & $1.5<|\eta|<2.1$ \\
|
262 |
|
|
\hline
|
263 |
|
|
20 - 22 & 0.00 $\pm$ 0.000 & 0.00 $\pm$ 0.000 & 0.00 $\pm$ 0.000 \\
|
264 |
|
|
22 - 24 & 0.03 $\pm$ 0.001 & 0.05 $\pm$ 0.001 & 0.11 $\pm$ 0.002 \\
|
265 |
|
|
24 - 26 & 0.87 $\pm$ 0.002 & 0.78 $\pm$ 0.002 & 0.76 $\pm$ 0.003 \\
|
266 |
|
|
26 - 28 & 0.90 $\pm$ 0.001 & 0.81 $\pm$ 0.002 & 0.78 $\pm$ 0.002 \\
|
267 |
|
|
28 - 30 & 0.91 $\pm$ 0.001 & 0.81 $\pm$ 0.002 & 0.79 $\pm$ 0.002 \\
|
268 |
|
|
30 - 32 & 0.91 $\pm$ 0.001 & 0.81 $\pm$ 0.001 & 0.80 $\pm$ 0.002 \\
|
269 |
|
|
32 - 34 & 0.92 $\pm$ 0.001 & 0.82 $\pm$ 0.001 & 0.80 $\pm$ 0.002 \\
|
270 |
|
|
34 - 36 & 0.93 $\pm$ 0.001 & 0.82 $\pm$ 0.001 & 0.81 $\pm$ 0.001 \\
|
271 |
|
|
36 - 38 & 0.93 $\pm$ 0.001 & 0.83 $\pm$ 0.001 & 0.81 $\pm$ 0.001 \\
|
272 |
|
|
38 - 40 & 0.93 $\pm$ 0.001 & 0.83 $\pm$ 0.001 & 0.82 $\pm$ 0.001 \\
|
273 |
|
|
40 - 50 & 0.94 $\pm$ 0.000 & 0.84 $\pm$ 0.000 & 0.82 $\pm$ 0.001 \\
|
274 |
|
|
50 - 60 & 0.95 $\pm$ 0.000 & 0.84 $\pm$ 0.001 & 0.83 $\pm$ 0.001 \\
|
275 |
|
|
60 - 80 & 0.95 $\pm$ 0.001 & 0.84 $\pm$ 0.002 & 0.83 $\pm$ 0.002 \\
|
276 |
|
|
80 - 100 & 0.94 $\pm$ 0.002 & 0.84 $\pm$ 0.004 & 0.83 $\pm$ 0.006 \\
|
277 |
|
|
100 - 150 & 0.94 $\pm$ 0.003 & 0.84 $\pm$ 0.005 & 0.83 $\pm$ 0.008 \\
|
278 |
|
|
150 - 200 & 0.93 $\pm$ 0.006 & 0.84 $\pm$ 0.011 & 0.82 $\pm$ 0.018 \\
|
279 |
|
|
$>$200 & 0.92 $\pm$ 0.010 & 0.82 $\pm$ 0.017 & 0.82 $\pm$ 0.031 \\
|
280 |
|
|
\hline
|
281 |
|
|
\hline
|
282 |
|
|
|
283 |
|
|
\end{tabular}
|
284 |
|
|
\end{center}
|
285 |
|
|
\end{table}
|
286 |
|
|
|
287 |
|
|
\begin{table}[htb]
|
288 |
|
|
\begin{center}
|
289 |
|
|
\footnotesize
|
290 |
|
|
\caption{\label{tab:eltriggeff}
|
291 |
|
|
Summary of the single electron trigger efficiency HLT\_Ele27\_WP80. Uncertainties are statistical.}
|
292 |
|
|
\begin{tabular}{c|c|c}
|
293 |
|
|
|
294 |
|
|
\hline
|
295 |
|
|
\hline
|
296 |
|
|
\pt\ range [GeV] & $|\eta|<1.5$ & $1.5<|\eta|<2.1$ \\
|
297 |
|
|
\hline
|
298 |
|
|
20 - 22 & 0.00 $\pm$ 0.000 & 0.00 $\pm$ 0.000 \\
|
299 |
|
|
22 - 24 & 0.00 $\pm$ 0.000 & 0.00 $\pm$ 0.001 \\
|
300 |
|
|
24 - 26 & 0.00 $\pm$ 0.000 & 0.02 $\pm$ 0.001 \\
|
301 |
|
|
26 - 28 & 0.08 $\pm$ 0.001 & 0.18 $\pm$ 0.003 \\
|
302 |
|
|
28 - 30 & 0.61 $\pm$ 0.002 & 0.50 $\pm$ 0.004 \\
|
303 |
|
|
30 - 32 & 0.86 $\pm$ 0.001 & 0.63 $\pm$ 0.003 \\
|
304 |
|
|
32 - 34 & 0.88 $\pm$ 0.001 & 0.68 $\pm$ 0.003 \\
|
305 |
|
|
34 - 36 & 0.90 $\pm$ 0.001 & 0.70 $\pm$ 0.002 \\
|
306 |
|
|
36 - 38 & 0.91 $\pm$ 0.001 & 0.72 $\pm$ 0.002 \\
|
307 |
|
|
38 - 40 & 0.92 $\pm$ 0.001 & 0.74 $\pm$ 0.002 \\
|
308 |
|
|
40 - 50 & 0.94 $\pm$ 0.000 & 0.76 $\pm$ 0.001 \\
|
309 |
|
|
50 - 60 & 0.95 $\pm$ 0.000 & 0.77 $\pm$ 0.002 \\
|
310 |
|
|
60 - 80 & 0.96 $\pm$ 0.001 & 0.78 $\pm$ 0.003 \\
|
311 |
|
|
80 - 100 & 0.96 $\pm$ 0.002 & 0.80 $\pm$ 0.008 \\
|
312 |
|
|
100 - 150 & 0.96 $\pm$ 0.002 & 0.79 $\pm$ 0.010 \\
|
313 |
|
|
150 - 200 & 0.97 $\pm$ 0.004 & 0.76 $\pm$ 0.026 \\
|
314 |
|
|
$>$200 & 0.97 $\pm$ 0.005 & 0.81 $\pm$ 0.038 \\
|
315 |
|
|
\hline
|
316 |
|
|
\hline
|
317 |
|
|
|
318 |
|
|
\end{tabular}
|
319 |
|
|
\end{center}
|
320 |
|
|
\end{table}
|
321 |
|
|
|
322 |
|
|
\clearpage
|