| 25 |
|
the $t\bar{t} \to$ dilepton BG estimate because it changes the |
| 26 |
|
$t\bar{t}$ normalization to the peak region (because some of the |
| 27 |
|
events in the peak region are from rare processes). These effects |
| 28 |
< |
are carefully accounted for. |
| 29 |
< |
%%%TO ADD BACK IN IF WE HAVE SYSTEMATICS TABLE. |
| 30 |
< |
%The contribution to the overall |
| 31 |
< |
%uncertainty from each BG source is tabulated in |
| 32 |
< |
%Section~\ref{sec:bgunc-bottomline}. |
| 28 |
> |
are carefully accounted for. The contribution to the overall |
| 29 |
> |
uncertainty from each background source is tabulated in |
| 30 |
> |
Section~\ref{sec:bgunc-bottomline}. |
| 31 |
|
Here we discuss the uncertainties one-by-one and comment |
| 32 |
|
on their impact on the overall result, at least to first order. |
| 33 |
|
Second order effects, such as the one described, are also included. |
| 152 |
|
15\% in SRG. |
| 153 |
|
|
| 154 |
|
|
| 155 |
< |
\subsection{Uncertainty on the \ttll\ Acceptance} |
| 155 |
> |
\subsection{Uncertainty on the \ttll\ Background} |
| 156 |
|
|
| 157 |
|
The \ttbar\ background prediction is obtained from MC, with corrections |
| 158 |
|
derived from control samples in data. The uncertainty associated with |
| 159 |
+ |
the \ttbar\ background is derived from the level of closure of the |
| 160 |
+ |
background prediction in CR4 (Table~\ref{tab:cr4yields}) and |
| 161 |
+ |
CR5 (Table~\ref{tab:cr5yields}). The results from these control region |
| 162 |
+ |
checks are shown in Figure~\ref{fig:ttdlunc}. The uncertainties assigned |
| 163 |
+ |
to the \ttdl\ background prediction based on these tests are |
| 164 |
+ |
5\% (SRA), 10\% (SRB), 15\% (SRC), 25\% (SRD), 40\% (SRE-G). |
| 165 |
+ |
|
| 166 |
+ |
\begin{figure}[hbt] |
| 167 |
+ |
\begin{center} |
| 168 |
+ |
\includegraphics[width=0.6\linewidth]{plots/ttdilepton_uncertainty.pdf} |
| 169 |
+ |
\caption{ |
| 170 |
+ |
\label{fig:ttdlunc}%\protect |
| 171 |
+ |
Results of the comparison of yields in the \mt\ tail comparing the MC prediction (after |
| 172 |
+ |
applying SFs) to data for CR4 and CR5 for all the signal |
| 173 |
+ |
region requirements considered (A-G). The bands indicate the |
| 174 |
+ |
systematic uncertainties assigned based on these tests, |
| 175 |
+ |
ranging from $5\%$ for SRA to $40\%$ for SRE-G.} |
| 176 |
+ |
\end{center} |
| 177 |
+ |
\end{figure} |
| 178 |
+ |
|
| 179 |
+ |
|
| 180 |
+ |
\subsubsection{Check of the uncertainty on the \ttll\ Acceptance} |
| 181 |
+ |
|
| 182 |
+ |
The uncertainty associated with |
| 183 |
|
the theoretical modeling of the \ttbar\ production and decay is |
| 184 |
< |
estimated by comparing the background predictions obtained using |
| 184 |
> |
checked by comparing the background predictions obtained using |
| 185 |
|
alternative MC samples. It should be noted that the full analysis is |
| 186 |
|
performed with the alternative samples under consideration, |
| 187 |
|
including the derivation of the various data-to-MC scale factors. |
| 383 |
|
uncertainty |
| 384 |
|
of 6\% would fully cover all of the variations from different MC |
| 385 |
|
samples in SRA and SRB. |
| 386 |
< |
{\bf Thus, we take a 6\% systematic uncertainty, constant as a |
| 387 |
< |
function of signal region, as the systematic due to alternative MC |
| 366 |
< |
models.} |
| 386 |
> |
The alternative MC models indicate that a 6\% systematic uncertainty to |
| 387 |
> |
cover the range of reasonable variations. |
| 388 |
|
Note that this 6\% is also consistent with the level at which we are |
| 389 |
< |
able |
| 390 |
< |
to test the closure of the method in CR5 for the high statistics |
| 391 |
< |
regions |
| 392 |
< |
(Table~\ref{tab:hugecr5yields}). |
| 393 |
< |
|
| 389 |
> |
able to test the closure of the method with alternative samples in CR5 for the high statistics |
| 390 |
> |
regions (Table~\ref{tab:hugecr5yields}). |
| 391 |
> |
The range of reasonable variations obtained with the alternative |
| 392 |
> |
samples are consistent with the uncertainties assigned for |
| 393 |
> |
the \ttll\ background based on the closure of the background |
| 394 |
> |
predictions and data in CR4 and CR5. |
| 395 |
|
|
| 396 |
|
|
| 397 |
|
|
| 864 |
|
\end{center} |
| 865 |
|
\end{table} |
| 866 |
|
|
| 867 |
+ |
\clearpage |
| 868 |
+ |
\subsection{Summary of uncertainties} |
| 869 |
+ |
\label{sec:bgunc-bottomline}. |
| 870 |
+ |
\input{uncertainties_table.tex} |
| 871 |
|
|
| 872 |
|
%Figure.~\ref{fig:reliso} compares the relative track isolation |
| 873 |
|
%for events with a track with $\pt > 10~\GeV$ in addition to a selected |
| 949 |
|
% \end{center} |
| 950 |
|
%\end{figure} |
| 951 |
|
|
| 952 |
< |
% \subsection{Summary of uncertainties} |
| 927 |
< |
% \label{sec:bgunc-bottomline}. |
| 952 |
> |
|
| 953 |
|
|
| 954 |
|
% THIS NEEDS TO BE WRITTEN |
