| 6 |
|
dilepton sample. The choice of signal region is driven by |
| 7 |
|
three observations: |
| 8 |
|
\begin{enumerate} |
| 9 |
< |
\item astrophisical evidence for dark matter suggests that |
| 9 |
> |
\item astrophysical evidence for dark matter suggests that |
| 10 |
|
we concentrate on the region of high \met; |
| 11 |
|
\item new physics signals should have high $\sqrt{\hat{s}}$; |
| 12 |
|
\item observable high cross section new physics signals |
| 17 |
|
Following these observations, we add the following two requirements |
| 18 |
|
to the preselection of Section~\ref{sec:eventSel}: |
| 19 |
|
\begin{center} |
| 20 |
< |
SumJetPt$>$300 GeV and $\met/\sqrt{\rm SumJetPt} > 8.5$. |
| 20 |
> |
$\mathrm{SumJetPt}>300$~GeV and $\met/\sqrt{\rm SumJetPt} > 8.5$~GeV$^{1/2}$. |
| 21 |
|
\end{center} |
| 22 |
|
|
| 23 |
|
\noindent This selection preserves about 1\% of the $t\bar{t}$ |
| 24 |
< |
signal. We cut on \met$/\sqrt{\rm SumJetPt}$ rather than \met |
| 25 |
< |
because the variables \met and \met$/\sqrt{\rm SumJetPt}$ are |
| 24 |
> |
signal. As shown in Table~\ref{tab:sigyield}, the expected total SM yield in 35 pb$^{-1}$ is 1.3 events, |
| 25 |
> |
while the expectations from the LMO and LM1 SUSY benchmark points are 6.3 and |
| 26 |
> |
2.6 events, respectively. |
| 27 |
> |
|
| 28 |
> |
|
| 29 |
> |
We cut on \met$/\sqrt{\rm SumJetPt}$ rather than \met |
| 30 |
> |
because the variables SumJetPt and \met$/\sqrt{\rm SumJetPt}$ are |
| 31 |
|
largely uncorrelated for the dominant $t\bar{t}$ background. |
| 32 |
|
This allows us to use a data driven ABCD method to estimate the |
| 33 |
|
background (see Section~\ref{sec:abcd}). |
| 34 |
+ |
|
| 35 |
+ |
|
| 36 |
+ |
|
| 37 |
+ |
|
| 38 |
+ |
\begin{table}[hbt] |
| 39 |
+ |
\begin{center} |
| 40 |
+ |
\caption{\label{tab:sigyield} MC expected yields in the signal region for 35~pb$^{-1}$. |
| 41 |
+ |
The errors are statistical only.} |
| 42 |
+ |
\begin{tabular}{lcccc} |
| 43 |
+ |
\hline |
| 44 |
+ |
Sample & $ee$ & $\mu\mu$ & $e\mu$ & tot \\ |
| 45 |
+ |
\hline |
| 46 |
+ |
$t\bar{t}\rightarrow \ell^{+}\ell^{-}$ & 0.27 $\pm$ 0.03 & 0.22 $\pm$ 0.03 & 0.56 $\pm$ 0.05 & 1.05 $\pm$ 0.06 \\ |
| 47 |
+ |
$t\bar{t}\rightarrow \mathrm{other}$ & 0.01 $\pm$ 0.01 & 0.00 $\pm$ 0.00 & 0.01 $\pm$ 0.01 & 0.02 $\pm$ 0.01 \\ |
| 48 |
+ |
$Z^0 \rightarrow \ell^{+}\ell^{-}$ & 0.05 $\pm$ 0.05 & 0.05 $\pm$ 0.05 & 0.05 $\pm$ 0.05 & 0.16 $\pm$ 0.09 \\ |
| 49 |
+ |
$W^{\pm}$ + jets & 0.00 $\pm$ 0.00 & 0.00 $\pm$ 0.00 & 0.00 $\pm$ 0.00 & 0.00 $\pm$ 0.00 \\ |
| 50 |
+ |
$W^+W^-$ & 0.00 $\pm$ 0.00 & 0.01 $\pm$ 0.00 & 0.02 $\pm$ 0.01 & 0.03 $\pm$ 0.01 \\ |
| 51 |
+ |
$W^{\pm}Z^0$ & 0.00 $\pm$ 0.00 & 0.00 $\pm$ 0.00 & 0.00 $\pm$ 0.00 & 0.00 $\pm$ 0.00 \\ |
| 52 |
+ |
$Z^0Z^0$ & 0.00 $\pm$ 0.00 & 0.00 $\pm$ 0.00 & 0.00 $\pm$ 0.00 & 0.00 $\pm$ 0.00 \\ |
| 53 |
+ |
single top & 0.00 $\pm$ 0.00 & 0.00 $\pm$ 0.00 & 0.01 $\pm$ 0.00 & 0.01 $\pm$ 0.00 \\ |
| 54 |
+ |
\hline |
| 55 |
+ |
total SM MC & 0.35 $\pm$ 0.06 & 0.29 $\pm$ 0.06 & 0.65 $\pm$ 0.07 & 1.29 $\pm$ 0.11 \\ |
| 56 |
+ |
\hline |
| 57 |
+ |
data & 0 & 0 & 1 & 1 \\ |
| 58 |
+ |
\hline |
| 59 |
+ |
LM0 & 1.75 $\pm$ 0.10 & 2.10 $\pm$ 0.11 & 2.42 $\pm$ 0.12 & 6.28 $\pm$ 0.20 \\ |
| 60 |
+ |
LM1 & 0.90 $\pm$ 0.03 & 1.10 $\pm$ 0.03 & 0.57 $\pm$ 0.02 & 2.57 $\pm$ 0.04 \\ |
| 61 |
+ |
\hline |
| 62 |
+ |
\end{tabular} |
| 63 |
+ |
\end{center} |
| 64 |
+ |
\end{table} |
