| 5 |
|
Here we walk the reader through a concrete example. |
| 6 |
|
|
| 7 |
|
{\bf NB: the numbers |
| 8 |
< |
in this section corresponded to the numbers in V2 of the analysis note. |
| 8 |
> |
in this section corresponded to the numbers in V3 of the analysis note. |
| 9 |
|
They will not be updated, because this is meant as an illustration only.}. |
| 10 |
|
|
| 11 |
< |
The main background is $t\bar{t}$ |
| 11 |
> |
The main background is $t\bar{t}$. |
| 12 |
|
The main idea is to normalize to the $M_T$ peak region ($50 < M_T < 80$ GeV). |
| 13 |
|
This eliminates dependence on \ttbar\ cross-section, luminosity, |
| 14 |
|
trigger efficiency, JES, lepton ID, etc. This gets a bit complicated because |
| 23 |
|
|
| 24 |
|
This complex procedure is important for the high statistics signal regions |
| 25 |
|
with relatively low \met\ requirements, eg, SRA. For these SRs we want to keep the |
| 26 |
< |
systematics low in order to be sensistive to low mass stop; for the signal regions |
| 26 |
> |
systematics low in order to be sensitive to low mass stop; for the signal regions |
| 27 |
|
with hard cuts on \met\, this is less important. However, we apply the same |
| 28 |
|
procedure to all SRs. |
| 29 |
|
|
| 76 |
|
|
| 77 |
|
\noindent $SF_{post} = (2787 - 62 - SF_{pre} \cdot 116) / (2595 + 236) = 0.924$. |
| 78 |
|
|
| 79 |
< |
Then the \ttsl\ background is obtained as the product of the following four factors |
| 79 |
> |
Then the \ttsl\ background is obtained as the product of the following three factors |
| 80 |
|
|
| 81 |
|
\begin{itemize} |
| 82 |
|
\item $SF_{post} = 0.924$ as obtained above |
| 83 |
|
\item 2595, from the third column of Table~\ref{tab:bgexample} |
| 84 |
< |
\item The tail-to-peak ratio $R_{top} = 0.015$ from Table~\ref{tab:ttp} (we use the average of electrons |
| 85 |
< |
and muons) |
| 86 |
< |
\item The tail-to-peak ratio scale factod $SFR_{top} = 1.89 \pm 0.56$ from Table~\ref{tab:cr2yields}. |
| 84 |
> |
\item The tail-to-peak ratio $R_{top} = 0.045$ from Table~\ref{tab:ttpcorr} |
| 85 |
> |
%\item The tail-to-peak ratio scale factor $SFR_{top} = 1.89 \pm 0.56$ from Table~\ref{tab:cr2yields}. |
| 86 |
|
\end{itemize} |
| 87 |
|
|
| 88 |
< |
The result for the central value is 68 events. |
| 88 |
> |
The result for the central value is 108 events. |
| 89 |
|
|
| 90 |
|
\subsection{Central value for the \wjets\ background} |
| 91 |
|
|
| 93 |
|
\begin{itemize} |
| 94 |
|
\item $SF_{post} = 0.924$ from Section~\ref{sec:cenvttlj} |
| 95 |
|
\item 236, from the third column of Table~\ref{tab:bgexample} |
| 96 |
< |
\item The tail-to-peak ratio $R_{wjet} = 0.04$ from Table~\ref{tab:ttp} (we use the average of electrons and muons) |
| 97 |
< |
\item The tail-to-peak ratio scale factod $SFR_{wjet} = 1.64 \pm 0.38$ from Table~\ref{tab:cr1yields}. |
| 96 |
> |
\item The tail-to-peak ratio $R_{wjet} = 0.066$ from Table~\ref{tab:ttpcorr} |
| 97 |
> |
%\item The tail-to-peak ratio scale factor $SFR_{wjet} = 1.64 \pm 0.38$ from Table~\ref{tab:cr1yields}. |
| 98 |
|
\end{itemize} |
| 99 |
|
|
| 100 |
|
The result for the central value is 14.3 events. |
