| 5 |
|
\centering |
| 6 |
|
%\begin{center} |
| 7 |
|
\begin{tabular}{cc} |
| 8 |
< |
\includegraphics[width=0.45\textwidth]{HCPPlots/AlphaT_le3j_prelim.pdf} & |
| 9 |
< |
\includegraphics[width=0.4\textwidth]{HCPPlots/hadronic_2b_le3j_logy.pdf} \\ |
| 8 |
> |
\subfloat[] {\includegraphics[width=0.45\textwidth]{HCPPlots/AlphaT_le3j_prelim.pdf}} & |
| 9 |
> |
\subfloat[] {\includegraphics[width=0.4\textwidth]{HCPPlots/hadronic_2b_le3j_logy.pdf}} \\ |
| 10 |
|
\end{tabular} |
| 11 |
|
\caption{ |
| 12 |
|
The distribution of the \alphat\ variable (left) and the $H_T$ distribution in data, compared to the SM background expectation (right). |
| 32 |
|
of the second leading jet and $M_T$ is the transverse mass of the dijet system. |
| 33 |
|
For events with perfectly measured jets, the measured \pt\ values of the two jets are equal, leading to $\alphat=0.5$. The key feature of the \alphat\ variable |
| 34 |
|
is that mismeasurement effects tend to decrease the value of \alphat, such that it is extremely rare for events with fake \met\ to have \alphat\ |
| 35 |
< |
much larger than 0.5. As shown in Fig.~\ref{fig:alphat}, the \alphat\ distribution for the QCD multijet background falls off extremely rapidly near this endpoint value. |
| 35 |
> |
much larger than 0.5. As shown in Fig.~\ref{fig:alphat}(a), the \alphat\ distribution for the QCD multijet background falls off extremely rapidly near this endpoint value. |
| 36 |
|
For events with three of more jets, an equivalent dijet system is formed by clustering the jets into two pseudo-jets. In our search we strongly suppress the |
| 37 |
|
QCD multijet background with the requirement \alphat\ $>$ 0.55. |
| 38 |
|
|
| 41 |
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These backgrounds are estimated using a $\mu+\rm{jets}$ data control sample. |
| 42 |
|
The additional background from $\rm{Z}(\nu\nu)+\rm{jets}$ is estimated using two data control samples of $\rm{Z}(\ell\ell)+\rm{jets}$ and $\gamma+\rm{jets}$ events. To estimate these backgrounds, the observed yields in the data control samples are extrapolated to the |
| 43 |
|
signal region using translation factors derived from MC. The dominant systematic uncertainties in the background prediction stem from the uncertainties |
| 44 |
< |
in the MC translation factors, which are assessed by performing several closure tests in data in which the observed yields in one data control region |
| 44 |
> |
in the MC translation factors, which are assessed by performing several closure tests in data. In these tests, the observed yields in one data control region |
| 45 |
|
are used to predict the yields in another data control region. |
| 46 |
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|
| 47 |
|
Events are categorized based on the $H_T$, jet multiplicity, and b-tagged jet multiplicity. For the bottom squark scenario described above, the most sensitive |
| 48 |
< |
category is events with either two or three jets and exactly two b-tagged jets. The $H_T$ distribution for these events is indicated in Fig.~\ref{fig:alphat}b, |
| 48 |
> |
category is events with either two or three jets and exactly two b-tagged jets. The $H_T$ distribution for these events is indicated in Fig.~\ref{fig:alphat}(b), |
| 49 |
|
which demonstrates good agreement between the data and the expected background. No evidence for an excess of events is observed. |
| 50 |
|
|
| 51 |
|
The results are interpreted using the model of bottom squark pair production with $\tilde{b}\to b\lsp$ in Fig.~\ref{fig:ss_interpretation}(b). |
