claudioc/dilNoteICHEP/introduction.tex

\section{Introduction}
\label{sec:intro}

In this note we describe a first study of isolated same sign (SS)
and opposite sign (OS) low $P_T$ ($P_T > 10$ GeV)
dileptons (e or $\mu$) 
in 7 TeV collision data.  Our goal is to understand this 
data sample as a first step towards a top cross-section
analysis~\cite{ref:topdil2009}, a $WW$ cross-section 
analysis~\cite{ref:WW}, as well as SS and OS SUSY 
searches\cite{ref:OSSusy}\cite{ref:SSSusy}.  

With a 10 GeV $P_T$ threshold, the data sample is dominated by QCD 
backgrounds and Drell-Yan events.  We compare the observed yields
with predictions from Monte Carlo.  In the case of QCD, we use
the Fake Rate method to predict its rate in a data driven way.
With the present luminosity, there is not enough statistics to
study kinematical distributions.

This note is organized as follows.  In Section~\ref{sec:datasets} 
we list the datasets used; the lepton identification criteria 
and the general event selection requirements 
are given in Section~\ref{sec:selection}; the event data yields are
compared with Monte Carlo expectations in Section~\ref{sec:yields};
the FR method is reviewed in Section~\ref{sec:FR};  the application
of the FR method is summarized in Section~\ref{sec:FRapply}.

{\color{red} This document was originally based on $\approx$ 10
nb$^{-1}$ of integrated luminosity.  It has now been partially 
updated to higher luminosity for ICHEP.  Following instructions
from the SUSY convenors, we leave the old results in the
document.  To facilitate reading, the document is color coded:
\begin{itemize}
\item everything in red is new
\item everything in {\color{blue}blue} is old information that has been updated
\item everything in {\color{black}black} is old information that has not 
been updated.  In the case of plots and results, these would still be 
with the $\approx$ 10 nb$^{-1}$.
\end{itemize}
}
Revision:	1.2
Committed:	Wed Jul 7 13:42:25 2010 UTC (14 years, 10 months ago) by claudioc
Content type:	application/x-tex
Branch:	MAIN
Changes since 1.1:	+13 -0 lines
Log Message:	First commit of the update for SUSY ICHEP
#	User	Rev	Content
1	claudioc	1.1	\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
28	claudioc	1.2	{\color{red} This document was originally based on $\approx$ 10
29			nb$^{-1}$ of integrated luminosity. It has now been partially
30			updated to higher luminosity for ICHEP. Following instructions
31			from the SUSY convenors, we leave the old results in the
32			document. To facilitate reading, the document is color coded:
33			\begin{itemize}
34			\item everything in red is new
35			\item everything in {\color{blue}blue} is old information that has been updated
36			\item everything in {\color{black}black} is old information that has not
37			been updated. In the case of plots and results, these would still be
38			with the $\approx$ 10 nb$^{-1}$.
39			\end{itemize}
40			}