| 13 |
|
in the case of the $W$ decaying to electron is the $Z+jets$ |
| 14 |
|
production. As signal and background have a \Z boson in the final |
| 15 |
|
state, we will concentrate on the third lepton which is an electron in |
| 16 |
< |
this study. |
| 16 |
> |
this study, assuming we have found a \Z boson that has fullfilled all |
| 17 |
> |
our requirements. |
| 18 |
|
|
| 19 |
< |
In order to select the \Z candidate in the events, we apply loose |
| 19 |
> |
In order to select the \W candidate in the events, we apply loose |
| 20 |
|
criteria. The loose sample contain a given number of signal events |
| 21 |
|
which contains a third isolated electron and a given number of |
| 22 |
|
background events which do not contains a third isolated |
| 40 |
|
$$ |
| 41 |
|
|
| 42 |
|
The estimation of $\epsilon_{tight}$ and $p_{fake}$ can be done using control |
| 43 |
< |
samples, containing electrons and jet respectively with high purity. The Tag and probe |
| 44 |
< |
method is used to determine signal efficiency $\epsilon_{tight}$. The rate |
| 43 |
> |
samples, containing electrons and jets respectively with high purity. The Tag and Probe |
| 44 |
> |
method is used to determine the signal efficiency $\epsilon_{tight}$. The rate |
| 45 |
|
will be derived from $Z \to e^+e^-$ samples. In the following section we |
| 46 |
|
describe the method used to determine $p_{fake}$. |
| 47 |
|
|
| 48 |
+ |
\begin{figure}[bt] |
| 49 |
+ |
\begin{center} |
| 50 |
+ |
\scalebox{0.6}{\includegraphics{figs/tight_eff_gumbo.eps}} |
| 51 |
+ |
\caption{Fraction of electron candidates passing the tight criteria |
| 52 |
+ |
in QCD event. No trigger requirement has been applied.} |
| 53 |
+ |
\label{fig:qcd_efftight_noHLT} |
| 54 |
+ |
\end{center} |
| 55 |
+ |
\end{figure} |
| 56 |
+ |
|
| 57 |
|
\subsection{Determination of $p_{fake}$} |
| 58 |
|
|
| 59 |
|
As the events will be most of the time triggered by the leptons coming |
| 79 |
|
applied to each reconstructed electron from this sample of jets from |
| 80 |
|
QCD and photon+jet. Then the tight criteria is applied on such loose |
| 81 |
|
electrons and the $p_{fake}$ is simply the ratio of this two |
| 82 |
< |
population. This ratio, given as a function of $Pt$ and $\eta$, is |
| 83 |
< |
showed in plots \ref{fig:qcd_zjet_est}. |
| 82 |
> |
population. This ratio is showed as a function of \pt and $\eta$ |
| 83 |
> |
for all loose electrons in QCD events in Figure~\ref{fig:qcd_efftight_noHLT}. |
| 84 |
> |
%This ratio, given as a function of $Pt$ and $\eta$, is |
| 85 |
> |
%showed in plots \ref{fig:qcd_zjet_est}. |
| 86 |
|
|
| 87 |
|
\subsection{Determination of $\epsilon_{tight}$} |
