| 1 |
%\section{Systematics Uncertainties on the Background Prediction}
|
| 2 |
%\label{sec:systematics}
|
| 3 |
|
| 4 |
[ADD INTRODUCTORY BLURB ON UNCERTAINTIES \\
|
| 5 |
ADD COMPARISONS OF ALL THE ALTERNATIVE SAMPLES FOR ALL THE SIGNAL
|
| 6 |
REGIONS \\
|
| 7 |
LIST ALL THE UNCERTAINTIES INCLUDED AND THEIR VALUES]
|
| 8 |
|
| 9 |
\subsection{Uncertainty on the \ttll\ Acceptance}
|
| 10 |
|
| 11 |
The \ttbar\ background prediction is obtained from MC, with corrections
|
| 12 |
derived from control samples in data. The uncertainty associated with
|
| 13 |
the theoretical modeling of the \ttbar\ production and decay is
|
| 14 |
estimated by comparing the background predictions obtained using
|
| 15 |
alternative MC samples. It should be noted that the full analysis is
|
| 16 |
performed with the alternative samples under consideration,
|
| 17 |
including the derivation of the various data-to-MC scale factors.
|
| 18 |
The variations considered are
|
| 19 |
|
| 20 |
\begin{itemize}
|
| 21 |
\item Top mass: The alternative values for the top mass differ
|
| 22 |
from the central value by $5~\GeV$: $m_{\mathrm{top}} = 178.5~\GeV$ and $m_{\mathrm{top}}
|
| 23 |
= 166.5~\GeV$.
|
| 24 |
\item Jet-parton matching scale: This corresponds to variations in the
|
| 25 |
scale at which the Matrix Element partons from Madgraph are matched
|
| 26 |
to Parton Shower partons from Pythia. The nominal value is
|
| 27 |
$x_q>20~\GeV$. The alternative values used are $x_q>10~\GeV$ and
|
| 28 |
$x_q>40~\GeV$.
|
| 29 |
\item Renormalization and factorization scale: The alternative samples
|
| 30 |
correspond to variations in the scale $\times 2$ and $\times 0.5$. The nominal
|
| 31 |
value for the scale used is $Q^2 = m_{\mathrm{top}}^2 +
|
| 32 |
\sum_{\mathrm{jets}} \pt^2$.
|
| 33 |
\item Alternative generators: Samples produced with different
|
| 34 |
generators include MC@NLO and Powheg (NLO generators) and
|
| 35 |
Pythia (LO). It may also be noted that MC@NLO uses Herwig6 for the
|
| 36 |
hadronisation, while POWHEG uses Pythia6.
|
| 37 |
\item Modeling of taus: The alternative sample does not include
|
| 38 |
Tauola and is otherwise identical to the Powheg sample.
|
| 39 |
This effect was studied earlier using 7~TeV samples and found to be negligible.
|
| 40 |
\item The PDF uncertainty is estimated following the PDF4LHC
|
| 41 |
recommendations[CITE]. The events are reweighted using alternative
|
| 42 |
PDF sets for CT10 and MSTW2008 and the uncertainties for each are derived using the
|
| 43 |
alternative eigenvector variations and the ``master equation''. In
|
| 44 |
addition, the NNPDF2.1 set with 100 replicas. The central value is
|
| 45 |
determined from the mean and the uncertainty is derived from the
|
| 46 |
$1\sigma$ range. The overall uncertainty is derived from the envelope of the
|
| 47 |
alternative predictions and their uncertainties.
|
| 48 |
This effect was studied earlier using 7~TeV samples and found to be negligible.
|
| 49 |
\end{itemize}
|
| 50 |
|
| 51 |
|
| 52 |
\begin{figure}[hbt]
|
| 53 |
\begin{center}
|
| 54 |
\includegraphics[width=0.8\linewidth]{plots/n_dl_syst_comp.png}
|
| 55 |
\caption{
|
| 56 |
\label{fig:ttllsyst}%\protect
|
| 57 |
Comparison of the \ttll\ central prediction with those using
|
| 58 |
alternative MC samples. The blue band corresponds to the
|
| 59 |
total statistical error for all data and MC samples. The
|
| 60 |
alternative sample predictions are indicated by the
|
| 61 |
datapoints. The uncertainties on the alternative predictions
|
| 62 |
correspond to the uncorrelated statistical uncertainty from
|
| 63 |
the size of the alternative sample only.}
|
| 64 |
\end{center}
|
| 65 |
\end{figure}
|
| 66 |
|
| 67 |
|
| 68 |
|
| 69 |
%
|
| 70 |
%
|
| 71 |
%The methodology for determining the systematics on the background
|
| 72 |
%predictions has not changed with respect to the nominal analysis.
|
| 73 |
%Because the template method has not changed, the same
|
| 74 |
%systematic uncertainty is assessed on this prediction (32\%).
|
| 75 |
%The 50\% uncertainty on the WZ and ZZ background is also unchanged.
|
| 76 |
%The systematic uncertainty in the OF background prediction based on
|
| 77 |
%e$\mu$ events has changed, due to the different composition of this
|
| 78 |
%sample after vetoing events containing b-tagged jets.
|
| 79 |
%
|
| 80 |
%As in the nominal analysis, we do not require the e$\mu$ events
|
| 81 |
%to satisfy the dilepton mass requirement and apply a scaling factor K,
|
| 82 |
%extracted from MC, to account for the fraction of e$\mu$ events
|
| 83 |
%which satisfy the dilepton mass requirement. This procedure is used
|
| 84 |
%in order to improve the statistical precision of the OF background estimate.
|
| 85 |
%
|
| 86 |
%For the selection used in the nominal analysis,
|
| 87 |
%the e$\mu$ sample is completely dominated by $t\bar{t}$
|
| 88 |
%events, and we observe that K is statistically consistent with constant with
|
| 89 |
%respect to the \MET\ requirement. However, in this analysis, the $t\bar{t}$
|
| 90 |
%background is strongly suppressed by the b-veto, and hence the non-$t\bar{t}$
|
| 91 |
%backgrounds (specifically, $Z\to\tau\tau$ and VV) become more relevant.
|
| 92 |
%At low \MET, the $Z\to\tau\tau$ background is pronounced, while $t\bar{t}$
|
| 93 |
%and VV dominate at high \MET\ (see App.~\ref{app:kinemu}).
|
| 94 |
%Therefore, the sample composition changes
|
| 95 |
%as the \MET\ requirement is varied, and as a result K depends
|
| 96 |
%on the \MET\ requirement.
|
| 97 |
%
|
| 98 |
%We thus measure K in MC separately for each
|
| 99 |
%\MET\ requirement, as displayed in Fig.~\ref{fig:kvmet} (left).
|
| 100 |
%%The systematic uncertainty on K is determined separately for each \MET\
|
| 101 |
%%requirement by comparing the relative difference in K in data vs. MC.
|
| 102 |
%The values of K used are the MC predictions
|
| 103 |
%%and the total systematic uncertainty on the OF prediction
|
| 104 |
%%as shown in
|
| 105 |
%(Table \ref{fig:kvmettable}).
|
| 106 |
%The contribution to the total OF prediction systematic uncertainty
|
| 107 |
%from K is assessed from the ratio of K in data and MC,
|
| 108 |
%shown in Fig.~\ref{fig:kvmet} (right).
|
| 109 |
%The ratio is consistent with unity to roughly 17\%,
|
| 110 |
%so we take this value as the systematic from K.
|
| 111 |
%17\% added in quadrature with 7\% from
|
| 112 |
%the electron to muon efficieny ratio
|
| 113 |
%(as assessed in the inclusive analysis)
|
| 114 |
%yields a total systematic of $\sim$18\%
|
| 115 |
%which we round up to 20\%.
|
| 116 |
%For \MET\ $>$ 150, there are no OF events in data inside the Z mass window
|
| 117 |
%so we take a systematic based on the statistical uncertainty
|
| 118 |
%of the MC prediction for K.
|
| 119 |
%This value is 25\% for \MET\ $>$ 150 GeV and 60\% for \MET\ $>$ 200 GeV.
|
| 120 |
%%Although we cannot check the value of K in data for \MET\ $>$ 150
|
| 121 |
%%because we find no OF events inside the Z mass window for this \MET\
|
| 122 |
%%cut, the overall OF yields with no dilepton mass requirement
|
| 123 |
%%agree to roughly 20\% (9 data vs 7.0 $\pm$ 1.1 MC).
|
| 124 |
%
|
| 125 |
%
|
| 126 |
%%Below Old
|
| 127 |
%
|
| 128 |
%%In reevaluating the systematics on the OF prediction, however,
|
| 129 |
%%we observed a different behavior of K as a function of \MET\
|
| 130 |
%%as was seen in the inclusive analysis.
|
| 131 |
%
|
| 132 |
%%Recall that K is the ratio of the number of \emu\ events
|
| 133 |
%%inside the Z window to the total number of \emu\ events.
|
| 134 |
%%In the inclusive analysis, it is taken from \ttbar\ MC
|
| 135 |
%%and used to scale the inclusive \emu\ yield in data.
|
| 136 |
%%The yield scaled by K is then corrected for
|
| 137 |
%%the $e$ vs $\mu$ efficiency difference to obtain the
|
| 138 |
%%final OF prediction.
|
| 139 |
%
|
| 140 |
%%Based on the plot in figure \ref{fig:kvmet},
|
| 141 |
%%we choose to use a different
|
| 142 |
%%K for each \MET\ cut and assess a systematic uncertainty
|
| 143 |
%%on the OF prediction based on the difference between
|
| 144 |
%%K in data and MC.
|
| 145 |
%%The variation of K as a function of \MET\ is caused
|
| 146 |
%%by a change in sample composition with increasing \MET.
|
| 147 |
%%At \MET\ $<$ 60 GeV, the contribution of Z plus jets is
|
| 148 |
%%not negligible (as it was in the inclusive analysis)
|
| 149 |
%%because of the b veto. (See appendix \ref{app:kinemu}.)
|
| 150 |
%%At higher \MET, \ttbar\ and diboson backgrounds dominate.
|
| 151 |
%
|
| 152 |
%
|
| 153 |
%
|
| 154 |
%
|
| 155 |
%\begin{figure}[hbt]
|
| 156 |
% \begin{center}
|
| 157 |
% \includegraphics[width=0.48\linewidth]{plots/kvmet_data_ttbm.pdf}
|
| 158 |
% \includegraphics[width=0.48\linewidth]{plots/kvmet_ratio.pdf}
|
| 159 |
% \caption{
|
| 160 |
% \label{fig:kvmet}\protect
|
| 161 |
% The left plot shows
|
| 162 |
% K as a function of \MET\ in MC (red) and data (black).
|
| 163 |
% The bin low edge corresponds to the \MET\ cut, and the
|
| 164 |
% bins are inclusive.
|
| 165 |
% The MC used is a sum of all SM MC used in the yield table of
|
| 166 |
% section \ref{sec:yields}.
|
| 167 |
% The right plot is the ratio of K in data to MC.
|
| 168 |
% The ratio is fit to a line whose slope is consistent with zero
|
| 169 |
% (the fit parameters are
|
| 170 |
% 0.9 $\pm$ 0.4 for the intercept and
|
| 171 |
% 0.001 $\pm$ 0.005 for the slope).
|
| 172 |
% }
|
| 173 |
% \end{center}
|
| 174 |
%\end{figure}
|
| 175 |
%
|
| 176 |
%
|
| 177 |
%
|
| 178 |
%\begin{table}[htb]
|
| 179 |
%\begin{center}
|
| 180 |
%\caption{\label{fig:kvmettable} The values of K used in the OF background prediction.
|
| 181 |
%The uncertainties shown are the total relative systematic used for the OF prediction,
|
| 182 |
%which is the systematic uncertainty from K added in quadrature with
|
| 183 |
%a 7\% uncertainty from the electron to muon efficieny ratio as assessed in the
|
| 184 |
%inclusive analysis.
|
| 185 |
%}
|
| 186 |
%\begin{tabular}{lcc}
|
| 187 |
%\hline
|
| 188 |
%\MET\ Cut & K & Relative Systematic \\
|
| 189 |
%\hline
|
| 190 |
%%the met zero row is used only for normalization of the money plot.
|
| 191 |
%%0 & 0.1 & \\
|
| 192 |
%30 & 0.12 & 20\% \\
|
| 193 |
%60 & 0.13 & 20\% \\
|
| 194 |
%80 & 0.12 & 20\% \\
|
| 195 |
%100 & 0.12 & 20\% \\
|
| 196 |
%150 & 0.09 & 25\% \\
|
| 197 |
%200 & 0.06 & 60\% \\
|
| 198 |
%\hline
|
| 199 |
%\end{tabular}
|
| 200 |
%\end{center}
|
| 201 |
%\end{table}
|
| 202 |
|
| 203 |
|
| 204 |
\subsection{Isolated Track Veto: Tag and Probe Studies}
|
| 205 |
|
| 206 |
[EVERYTHING IS 7TEV HERE, UPDATE WITH NEW RESULTS \\
|
| 207 |
ADD TABLE WITH FRACTION OF EVENTS THAT HAVE A TRUE ISOLATED TRACK]
|
| 208 |
|
| 209 |
In this section we compare the performance of the isolated track veto in data and MC using tag-and-probe studies
|
| 210 |
with samples of Z$\to$ee and Z$\to\mu\mu$. The purpose of these studies is to demonstrate that the efficiency
|
| 211 |
to satisfy the isolated track veto requirements is well-reproduced in the MC, since if this were not the case
|
| 212 |
we would need to apply a data-to-MC scale factor in order to correctly predict the \ttll\ background. This study
|
| 213 |
addresses possible data vs. MC discrepancies for the {\bf efficiency} to identify (and reject) events with a
|
| 214 |
second {\bf genuine} lepton (e, $\mu$, or $\tau\to$1-prong). It does not address possible data vs. MC discrepancies
|
| 215 |
in the fake rate for rejecting events without a second genuine lepton; this is handled separately in the top normalization
|
| 216 |
procedure by scaling the \ttlj\ contribution to match the data in the \mt\ peak after applying the isolated track veto.
|
| 217 |
Furthermore, we test the data and MC
|
| 218 |
isolated track veto efficiencies for electrons and muons since we are using a Z tag-and-probe technique, but we do not
|
| 219 |
directly test the performance for hadronic tracks from $\tau$ decays. The performance for hadronic $\tau$ decay products
|
| 220 |
may differ from that of electrons and muons for two reasons. First, the $\tau$ may decay to a hadronic track plus one
|
| 221 |
or two $\pi^0$'s, which may decay to $\gamma\gamma$ followed by a photon conversion. As shown in Figure~\ref{fig:absiso},
|
| 222 |
the isolation distribution for charged tracks from $\tau$ decays that are not produced in association with $\pi^0$s are
|
| 223 |
consistent with that from $\E$s and $\M$s. Since events from single prong $\tau$ decays produced in association with
|
| 224 |
$\pi^0$s comprise a small fraction of the total sample, and since the kinematics of $\tau$, $\pi^0$ and $\gamma\to e^+e^-$
|
| 225 |
decays are well-understood, we currently demonstrate that the isolation is well-reproduced for electrons and muons only.
|
| 226 |
Second, hadronic tracks may undergo nuclear interactions and hence their tracks may not be reconstructed.
|
| 227 |
As discussed above, independent studies show that the MC reproduces the hadronic tracking efficiency within 4\%,
|
| 228 |
leading to a total background uncertainty of less than 0.5\% (after taking into account the fraction of the total background
|
| 229 |
due to hadronic $\tau$ decays with \pt\ $>$ 10 GeV tracks), and we hence regard this effect as neglgigible.
|
| 230 |
|
| 231 |
The tag-and-probe studies are performed in the full 2011 data sample, and compared with the DYJets madgraph sample.
|
| 232 |
All events must contain a tag-probe pair (details below) with opposite-sign and satisfying the Z mass requirement 76--106 GeV.
|
| 233 |
We compare the distributions of absolute track isolation for probe electrons/muons in data vs. MC. The contributions to
|
| 234 |
this isolation sum are from ambient energy in the event from underlying event, pile-up and jet activitiy, and hence do
|
| 235 |
not depend on the \pt\ of the probe lepton. We therefore restrict the probe \pt\ to be $>$ 30 GeV in order to suppress
|
| 236 |
fake backgrounds with steeply-falling \pt\ spectra. To suppress non-Z backgrounds (in particular \ttbar) we require
|
| 237 |
\met\ $<$ 30 GeV and 0 b-tagged events.
|
| 238 |
The specific criteria for tags and probes for electrons and muons are:
|
| 239 |
|
| 240 |
%We study the isolated track veto efficiency in bins of \njets.
|
| 241 |
%We are interested in events with at least 4 jets to emulate the hadronic activity in our signal sample. However since
|
| 242 |
%there are limited statistics for Z + $\geq$4 jet events, we study the isolated track performance in events with
|
| 243 |
|
| 244 |
|
| 245 |
\begin{itemize}
|
| 246 |
\item{Electrons}
|
| 247 |
|
| 248 |
\begin{itemize}
|
| 249 |
\item{Tag criteria}
|
| 250 |
|
| 251 |
\begin{itemize}
|
| 252 |
\item Electron passes full analysis ID/iso selection
|
| 253 |
\item \pt\ $>$ 30 GeV, $|\eta|<2.5$
|
| 254 |
|
| 255 |
\item Matched to 1 of the 2 electron tag-and-probe triggers
|
| 256 |
\begin{itemize}
|
| 257 |
\item \verb=HLT_Ele17_CaloIdVT_CaloIsoVT_TrkIdT_TrkIsoVT_SC8_Mass30_v*=
|
| 258 |
\item \verb=HLT_Ele17_CaloIdVT_CaloIsoVT_TrkIdT_TrkIsoVT_Ele8_Mass30_v*=
|
| 259 |
\end{itemize}
|
| 260 |
\end{itemize}
|
| 261 |
|
| 262 |
\item{Probe criteria}
|
| 263 |
\begin{itemize}
|
| 264 |
\item Electron passes full analysis ID selection
|
| 265 |
\item \pt\ $>$ 30 GeV
|
| 266 |
\end{itemize}
|
| 267 |
\end{itemize}
|
| 268 |
\item{Muons}
|
| 269 |
\begin{itemize}
|
| 270 |
\item{Tag criteria}
|
| 271 |
\begin{itemize}
|
| 272 |
\item Muon passes full analysis ID/iso selection
|
| 273 |
\item \pt\ $>$ 30 GeV, $|\eta|<2.1$
|
| 274 |
\item Matched to 1 of the 2 electron tag-and-probe triggers
|
| 275 |
\begin{itemize}
|
| 276 |
\item \verb=HLT_IsoMu30_v*=
|
| 277 |
\item \verb=HLT_IsoMu30_eta2p1_v*=
|
| 278 |
\end{itemize}
|
| 279 |
\end{itemize}
|
| 280 |
\item{Probe criteria}
|
| 281 |
\begin{itemize}
|
| 282 |
\item Muon passes full analysis ID selection
|
| 283 |
\item \pt\ $>$ 30 GeV
|
| 284 |
\end{itemize}
|
| 285 |
\end{itemize}
|
| 286 |
\end{itemize}
|
| 287 |
|
| 288 |
The absolute track isolation distributions for passing probes are displayed in Fig.~\ref{fig:tnp}. In general we observe
|
| 289 |
good agreement between data and MC. To be more quantitative, we compare the data vs. MC efficiencies to satisfy
|
| 290 |
absolute track isolation requirements varying from $>$ 1 GeV to $>$ 5 GeV, as summarized in Table~\ref{tab:isotrk}.
|
| 291 |
In the $\geq$0 and $\geq$1 jet bins where the efficiencies can be tested with statistical precision, the data and MC
|
| 292 |
efficiencies agree within 7\%, and we apply this as a systematic uncertainty on the isolated track veto efficiency.
|
| 293 |
For the higher jet multiplicity bins the statistical precision decreases, but we do not observe any evidence for
|
| 294 |
a data vs. MC discrepancy in the isolated track veto efficiency.
|
| 295 |
|
| 296 |
|
| 297 |
%This is because our analysis requirement is relative track isolation $<$ 0.1, and m
|
| 298 |
%This requirement is chosen because most of the tracks rejected by the isolated
|
| 299 |
%track veto have a \pt\ near the 10 GeV threshold, and our analysis requirement is relative track isolation $<$ 1 GeV.
|
| 300 |
|
| 301 |
\begin{figure}[hbt]
|
| 302 |
\begin{center}
|
| 303 |
%\includegraphics[width=0.3\linewidth]{plots/el_tkiso_0j.pdf}%
|
| 304 |
%\includegraphics[width=0.3\linewidth]{plots/mu_tkiso_0j.pdf}
|
| 305 |
%\includegraphics[width=0.3\linewidth]{plots/el_tkiso_1j.pdf}%
|
| 306 |
%\includegraphics[width=0.3\linewidth]{plots/mu_tkiso_1j.pdf}
|
| 307 |
%\includegraphics[width=0.3\linewidth]{plots/el_tkiso_2j.pdf}%
|
| 308 |
%\includegraphics[width=0.3\linewidth]{plots/mu_tkiso_2j.pdf}
|
| 309 |
%\includegraphics[width=0.3\linewidth]{plots/el_tkiso_3j.pdf}%
|
| 310 |
%\includegraphics[width=0.3\linewidth]{plots/mu_tkiso_3j.pdf}
|
| 311 |
%\includegraphics[width=0.3\linewidth]{plots/el_tkiso_4j.pdf}%
|
| 312 |
%\includegraphics[width=0.3\linewidth]{plots/mu_tkiso_4j.pdf}
|
| 313 |
\caption{
|
| 314 |
\label{fig:tnp} Comparison of the absolute track isolation in data vs. MC for electrons (left) and muons (right)
|
| 315 |
for events with the \njets\ requirement varied from \njets\ $\geq$ 0 to \njets\ $\geq$ 4.
|
| 316 |
}
|
| 317 |
\end{center}
|
| 318 |
\end{figure}
|
| 319 |
|
| 320 |
\clearpage
|
| 321 |
|
| 322 |
\begin{table}[!ht]
|
| 323 |
\begin{center}
|
| 324 |
\caption{\label{tab:isotrk} Comparison of the data vs. MC efficiencies to satisfy the indicated requirements
|
| 325 |
on the absolute track isolation, and the ratio of these two efficiencies. Results are indicated separately for electrons and muons and for various
|
| 326 |
jet multiplicity requirements.}
|
| 327 |
\begin{tabular}{l|l|c|c|c|c|c}
|
| 328 |
\hline
|
| 329 |
\hline
|
| 330 |
e + $\geq$0 jets & $>$ 1 GeV & $>$ 2 GeV & $>$ 3 GeV & $>$ 4 GeV & $>$ 5 GeV \\
|
| 331 |
\hline
|
| 332 |
data & 0.088 $\pm$ 0.0003 & 0.030 $\pm$ 0.0002 & 0.013 $\pm$ 0.0001 & 0.007 $\pm$ 0.0001 & 0.005 $\pm$ 0.0001 \\
|
| 333 |
mc & 0.087 $\pm$ 0.0001 & 0.030 $\pm$ 0.0001 & 0.014 $\pm$ 0.0001 & 0.008 $\pm$ 0.0000 & 0.005 $\pm$ 0.0000 \\
|
| 334 |
data/mc & 1.01 $\pm$ 0.00 & 0.99 $\pm$ 0.01 & 0.97 $\pm$ 0.01 & 0.95 $\pm$ 0.01 & 0.93 $\pm$ 0.01 \\
|
| 335 |
\hline
|
| 336 |
\hline
|
| 337 |
$\mu$ + $\geq$0 jets & $>$ 1 GeV & $>$ 2 GeV & $>$ 3 GeV & $>$ 4 GeV & $>$ 5 GeV \\
|
| 338 |
\hline
|
| 339 |
data & 0.087 $\pm$ 0.0002 & 0.031 $\pm$ 0.0001 & 0.015 $\pm$ 0.0001 & 0.008 $\pm$ 0.0001 & 0.005 $\pm$ 0.0001 \\
|
| 340 |
mc & 0.085 $\pm$ 0.0001 & 0.030 $\pm$ 0.0001 & 0.014 $\pm$ 0.0000 & 0.008 $\pm$ 0.0000 & 0.005 $\pm$ 0.0000 \\
|
| 341 |
data/mc & 1.02 $\pm$ 0.00 & 1.06 $\pm$ 0.00 & 1.06 $\pm$ 0.01 & 1.03 $\pm$ 0.01 & 1.02 $\pm$ 0.01 \\
|
| 342 |
\hline
|
| 343 |
\hline
|
| 344 |
e + $\geq$1 jets & $>$ 1 GeV & $>$ 2 GeV & $>$ 3 GeV & $>$ 4 GeV & $>$ 5 GeV \\
|
| 345 |
\hline
|
| 346 |
data & 0.099 $\pm$ 0.0008 & 0.038 $\pm$ 0.0005 & 0.019 $\pm$ 0.0004 & 0.011 $\pm$ 0.0003 & 0.008 $\pm$ 0.0002 \\
|
| 347 |
mc & 0.100 $\pm$ 0.0004 & 0.038 $\pm$ 0.0003 & 0.019 $\pm$ 0.0002 & 0.012 $\pm$ 0.0002 & 0.008 $\pm$ 0.0001 \\
|
| 348 |
data/mc & 0.99 $\pm$ 0.01 & 1.00 $\pm$ 0.02 & 0.99 $\pm$ 0.02 & 0.98 $\pm$ 0.03 & 0.97 $\pm$ 0.03 \\
|
| 349 |
\hline
|
| 350 |
\hline
|
| 351 |
$\mu$ + $\geq$1 jets & $>$ 1 GeV & $>$ 2 GeV & $>$ 3 GeV & $>$ 4 GeV & $>$ 5 GeV \\
|
| 352 |
\hline
|
| 353 |
data & 0.100 $\pm$ 0.0006 & 0.041 $\pm$ 0.0004 & 0.022 $\pm$ 0.0003 & 0.014 $\pm$ 0.0002 & 0.010 $\pm$ 0.0002 \\
|
| 354 |
mc & 0.099 $\pm$ 0.0004 & 0.039 $\pm$ 0.0002 & 0.020 $\pm$ 0.0002 & 0.013 $\pm$ 0.0001 & 0.009 $\pm$ 0.0001 \\
|
| 355 |
data/mc & 1.01 $\pm$ 0.01 & 1.05 $\pm$ 0.01 & 1.05 $\pm$ 0.02 & 1.06 $\pm$ 0.02 & 1.06 $\pm$ 0.03 \\
|
| 356 |
\hline
|
| 357 |
\hline
|
| 358 |
e + $\geq$2 jets & $>$ 1 GeV & $>$ 2 GeV & $>$ 3 GeV & $>$ 4 GeV & $>$ 5 GeV \\
|
| 359 |
\hline
|
| 360 |
data & 0.105 $\pm$ 0.0020 & 0.042 $\pm$ 0.0013 & 0.021 $\pm$ 0.0009 & 0.013 $\pm$ 0.0007 & 0.009 $\pm$ 0.0006 \\
|
| 361 |
mc & 0.109 $\pm$ 0.0011 & 0.043 $\pm$ 0.0007 & 0.021 $\pm$ 0.0005 & 0.013 $\pm$ 0.0004 & 0.009 $\pm$ 0.0003 \\
|
| 362 |
data/mc & 0.96 $\pm$ 0.02 & 0.97 $\pm$ 0.03 & 1.00 $\pm$ 0.05 & 1.01 $\pm$ 0.06 & 0.97 $\pm$ 0.08 \\
|
| 363 |
\hline
|
| 364 |
\hline
|
| 365 |
$\mu$ + $\geq$2 jets & $>$ 1 GeV & $>$ 2 GeV & $>$ 3 GeV & $>$ 4 GeV & $>$ 5 GeV \\
|
| 366 |
\hline
|
| 367 |
data & 0.106 $\pm$ 0.0016 & 0.045 $\pm$ 0.0011 & 0.025 $\pm$ 0.0008 & 0.016 $\pm$ 0.0007 & 0.012 $\pm$ 0.0006 \\
|
| 368 |
mc & 0.108 $\pm$ 0.0009 & 0.044 $\pm$ 0.0006 & 0.024 $\pm$ 0.0004 & 0.016 $\pm$ 0.0004 & 0.011 $\pm$ 0.0003 \\
|
| 369 |
data/mc & 0.98 $\pm$ 0.02 & 1.04 $\pm$ 0.03 & 1.04 $\pm$ 0.04 & 1.04 $\pm$ 0.05 & 1.06 $\pm$ 0.06 \\
|
| 370 |
\hline
|
| 371 |
\hline
|
| 372 |
e + $\geq$3 jets & $>$ 1 GeV & $>$ 2 GeV & $>$ 3 GeV & $>$ 4 GeV & $>$ 5 GeV \\
|
| 373 |
\hline
|
| 374 |
data & 0.117 $\pm$ 0.0055 & 0.051 $\pm$ 0.0038 & 0.029 $\pm$ 0.0029 & 0.018 $\pm$ 0.0023 & 0.012 $\pm$ 0.0019 \\
|
| 375 |
mc & 0.120 $\pm$ 0.0031 & 0.052 $\pm$ 0.0021 & 0.027 $\pm$ 0.0015 & 0.018 $\pm$ 0.0012 & 0.013 $\pm$ 0.0011 \\
|
| 376 |
data/mc & 0.97 $\pm$ 0.05 & 0.99 $\pm$ 0.08 & 1.10 $\pm$ 0.13 & 1.03 $\pm$ 0.15 & 0.91 $\pm$ 0.16 \\
|
| 377 |
\hline
|
| 378 |
\hline
|
| 379 |
$\mu$ + $\geq$3 jets & $>$ 1 GeV & $>$ 2 GeV & $>$ 3 GeV & $>$ 4 GeV & $>$ 5 GeV \\
|
| 380 |
\hline
|
| 381 |
data & 0.111 $\pm$ 0.0044 & 0.050 $\pm$ 0.0030 & 0.029 $\pm$ 0.0024 & 0.019 $\pm$ 0.0019 & 0.014 $\pm$ 0.0017 \\
|
| 382 |
mc & 0.115 $\pm$ 0.0025 & 0.051 $\pm$ 0.0017 & 0.030 $\pm$ 0.0013 & 0.020 $\pm$ 0.0011 & 0.015 $\pm$ 0.0009 \\
|
| 383 |
data/mc & 0.97 $\pm$ 0.04 & 0.97 $\pm$ 0.07 & 0.95 $\pm$ 0.09 & 0.97 $\pm$ 0.11 & 0.99 $\pm$ 0.13 \\
|
| 384 |
\hline
|
| 385 |
\hline
|
| 386 |
e + $\geq$4 jets & $>$ 1 GeV & $>$ 2 GeV & $>$ 3 GeV & $>$ 4 GeV & $>$ 5 GeV \\
|
| 387 |
\hline
|
| 388 |
data & 0.113 $\pm$ 0.0148 & 0.048 $\pm$ 0.0100 & 0.033 $\pm$ 0.0083 & 0.020 $\pm$ 0.0065 & 0.017 $\pm$ 0.0062 \\
|
| 389 |
mc & 0.146 $\pm$ 0.0092 & 0.064 $\pm$ 0.0064 & 0.034 $\pm$ 0.0048 & 0.024 $\pm$ 0.0040 & 0.021 $\pm$ 0.0037 \\
|
| 390 |
data/mc & 0.78 $\pm$ 0.11 & 0.74 $\pm$ 0.17 & 0.96 $\pm$ 0.28 & 0.82 $\pm$ 0.30 & 0.85 $\pm$ 0.34 \\
|
| 391 |
\hline
|
| 392 |
\hline
|
| 393 |
$\mu$ + $\geq$4 jets & $>$ 1 GeV & $>$ 2 GeV & $>$ 3 GeV & $>$ 4 GeV & $>$ 5 GeV \\
|
| 394 |
\hline
|
| 395 |
data & 0.130 $\pm$ 0.0128 & 0.052 $\pm$ 0.0085 & 0.028 $\pm$ 0.0063 & 0.019 $\pm$ 0.0052 & 0.019 $\pm$ 0.0052 \\
|
| 396 |
mc & 0.105 $\pm$ 0.0064 & 0.045 $\pm$ 0.0043 & 0.027 $\pm$ 0.0034 & 0.019 $\pm$ 0.0028 & 0.014 $\pm$ 0.0024 \\
|
| 397 |
data/mc & 1.23 $\pm$ 0.14 & 1.18 $\pm$ 0.22 & 1.03 $\pm$ 0.27 & 1.01 $\pm$ 0.32 & 1.37 $\pm$ 0.45 \\
|
| 398 |
\hline
|
| 399 |
\hline
|
| 400 |
|
| 401 |
\end{tabular}
|
| 402 |
\end{center}
|
| 403 |
\end{table}
|
| 404 |
|
| 405 |
|
| 406 |
|
| 407 |
%Figure.~\ref{fig:reliso} compares the relative track isolation
|
| 408 |
%for events with a track with $\pt > 10~\GeV$ in addition to a selected
|
| 409 |
%muon for $\Z+4$ jet events and various \ttll\ components. The
|
| 410 |
%isolation distributions show significant differences, particularly
|
| 411 |
%between the leptons from a \W\ or \Z\ decay and the tracks arising
|
| 412 |
%from $\tau$ decays. As can also be seen in the figure, the \pt\
|
| 413 |
%distribution for the various categories of tracks is different, where
|
| 414 |
%the decay products from $\tau$s are significantly softer. Since the
|
| 415 |
%\pt\ enters the denominator of the isolation definition and hence
|
| 416 |
%alters the isolation variable...
|
| 417 |
|
| 418 |
%\begin{figure}[hbt]
|
| 419 |
% \begin{center}
|
| 420 |
% \includegraphics[width=0.5\linewidth]{plots/pfiso_njets4_log.png}%
|
| 421 |
% \includegraphics[width=0.5\linewidth]{plots/pfpt_njets4.png}
|
| 422 |
% \caption{
|
| 423 |
% \label{fig:reliso}%\protect
|
| 424 |
% Comparison of relative track isolation variable for PF cand probe in Z+jets and ttbar
|
| 425 |
% Z+Jets and ttbar dilepton have similar isolation distributions
|
| 426 |
% ttbar with leptonic and single prong taus tend to be less
|
| 427 |
% isolated. The difference in the isolation can be attributed
|
| 428 |
% to the different \pt\ distribution of the samples, since
|
| 429 |
% $\tau$ decay products tend to be softer than leptons arising
|
| 430 |
% from \W\ or \Z\ decays.}
|
| 431 |
% \end{center}
|
| 432 |
%\end{figure}
|
| 433 |
|
| 434 |
% \includegraphics[width=0.5\linewidth]{plots/pfabsiso_njets4_log.png}
|
| 435 |
|
| 436 |
|
| 437 |
%BEGIN SECTION TO WRITE OUT
|
| 438 |
%In detail, the procedure to correct the dilepton background is:
|
| 439 |
|
| 440 |
%\begin{itemize}
|
| 441 |
%\item Using tag-and-probe studies, we plot the distribution of {\bf absolute} track isolation for identified probe electrons
|
| 442 |
%and muons {\bf TODO: need to compare the e vs. $\mu$ track iso distributions, they might differ due to e$\to$e$\gamma$}.
|
| 443 |
%\item We verify that the distribution of absolute track isolation does not depend on the \pt\ of the probe lepton.
|
| 444 |
%This is due to the fact that this isolation is from ambient PU and jet activity in the event, which is uncorrelated with
|
| 445 |
%the lepton \pt {\bf TODO: verify this in data and MC.}.
|
| 446 |
%\item Our requirement is {\bf relative} track isolation $<$ 0.1. For a given \ttll\ MC event, we determine the \pt of the 2nd
|
| 447 |
%lepton and translate this to find the corresponding requirement on the {\bf absolute} track isolation, which is simply $0.1\times$\pt.
|
| 448 |
%\item We measure the efficiency to satisfy this requirement in data and MC, and define a scale-factor $SF_{\epsilon(trk)}$ which
|
| 449 |
%is the ratio of the data-to-MC efficiencies. This scale-factor is applied to the \ttll\ MC event.
|
| 450 |
%\item {\bf THING 2 we are unsure about: we can measure this SF for electrons and for muons, but we can't measure it for hadronic
|
| 451 |
%tracks from $\tau$ decays. Verena has showed that the absolute track isolation distribution in hadronic $\tau$ tracks is harder due
|
| 452 |
%to $\pi^0\to\gamma\gamma$ with $\gamma\to e^+e^-$.}
|
| 453 |
%\end{itemize}
|
| 454 |
%END SECTION TO WRITE OUT
|
| 455 |
|
| 456 |
|
| 457 |
{\bf fix me: What you have written in the next paragraph does not explain how $\epsilon_{fake}$ is measured.
|
| 458 |
Why not measure $\epsilon_{fake}$ in the b-veto region?}
|
| 459 |
|
| 460 |
%A measurement of the $\epsilon_{fake}$ in data is non-trivial. However, it is
|
| 461 |
%possible to correct for differences in the $\epsilon_{fake}$ between data and MC by
|
| 462 |
%applying an additional scale factor for the single lepton background
|
| 463 |
%alone, using the sample in the \mt\ peak region. This scale factor is determined after applying the isolated track
|
| 464 |
%veto and after subtracting the \ttll\ component, corrected for the
|
| 465 |
%isolation efficiency derived previously.
|
| 466 |
%As shown in Figure~\ref{fig:vetoeffcomp}, the efficiency for selecting an
|
| 467 |
%isolated track in single lepton events is independent of \mt\, so the use of
|
| 468 |
%an overall scale factor is justified to estimate the contribution in
|
| 469 |
%the \mt\ tail.
|
| 470 |
%
|
| 471 |
%\begin{figure}[hbt]
|
| 472 |
% \begin{center}
|
| 473 |
% \includegraphics[width=0.5\linewidth]{plots/vetoeff_comp.png}
|
| 474 |
% \caption{
|
| 475 |
% \label{fig:vetoeffcomp}%\protect
|
| 476 |
% Efficiency for selecting an isolated track comparing
|
| 477 |
% single lepton \ttlj\ and dilepton \ttll\ events in MC and
|
| 478 |
% data as a function of \mt. The
|
| 479 |
% efficiencies in \ttlj\ and \ttll\ exhibit no dependence on
|
| 480 |
% \mt\, while the data ranges between the two. This behavior
|
| 481 |
% is expected since the low \mt\ region is predominantly \ttlj, while the
|
| 482 |
% high \mt\ region contains mostly \ttll\ events.}
|
| 483 |
% \end{center}
|
| 484 |
%\end{figure}
|
| 485 |
|
