| 1 |
\section{Introduction}
|
| 2 |
\label{sec:intro}
|
| 3 |
|
| 4 |
In this note we describe a first study of isolated same sign (SS)
|
| 5 |
and opposite sign (OS) low $P_T$ ($P_T > 10$ GeV)
|
| 6 |
dileptons (e or $\mu$)
|
| 7 |
in 7 TeV collision data. Our goal is to understand this
|
| 8 |
data sample as a first step towards a top cross-section
|
| 9 |
analysis~\cite{ref:topdil2009}, a $WW$ cross-section
|
| 10 |
analysis~\cite{ref:WW}, as well as SS and OS SUSY
|
| 11 |
searches\cite{ref:OSSusy}\cite{ref:SSSusy}.
|
| 12 |
|
| 13 |
With a 10 GeV $P_T$ threshold, the data sample is dominated by QCD
|
| 14 |
backgrounds and Drell-Yan events. We compare the observed yields
|
| 15 |
with predictions from Monte Carlo. In the case of QCD, we use
|
| 16 |
the Fake Rate method to predict its rate in a data driven way.
|
| 17 |
With the present luminosity, there is not enough statistics to
|
| 18 |
study kinematical distributions.
|
| 19 |
|
| 20 |
This note is organized as follows. In Section~\ref{sec:datasets}
|
| 21 |
we list the datasets used; the lepton identification criteria
|
| 22 |
and the general event selection requirements
|
| 23 |
are given in Section~\ref{sec:selection}; the event data yields are
|
| 24 |
compared with Monte Carlo expectations in Section~\ref{sec:yields};
|
| 25 |
the FR method is reviewed in Section~\ref{sec:FR}; the application
|
| 26 |
of the FR method is summarized in Section~\ref{sec:FRapply}.
|
| 27 |
|
