217 lines
8.3 KiB
TeX
217 lines
8.3 KiB
TeX
\documentclass[noback]{cuposter}
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%%\documentclass[noback,portrait]{cuposter}
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%% To make a poster in portrait, use the "portrait" option to
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%% documentclass as shown above.
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\usepackage{mathptmx}
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\usepackage{xspace}
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\usepackage{amsmath}
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\usepackage{pifont}
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\usepackage{psfrag}
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\usepackage{wrapfig}
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\usepackage{color}
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%%%%%%%%%%%%%%%%%%%%%
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\begin{document}
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%% Not needed for most posters.
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%%\renewcommand{\poster@ancimage}{/tmp/empty.ps}
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\newcommand{\don}{\ensuremath{d_{\textsc{ON}}}}
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\newcommand{\doff}{\ensuremath{d_{\textsc{OFF}}}}
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\newcommand{\dsoma}{\ensuremath{d_{\textsc{SOMA}}} \xspace}
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\newcommand{\um}{\ensuremath{\mu \text{m}}\xspace}
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\newcommand{\dmin}{d$_{\textup{min}}$\xspace}
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%\title{Status report: \\Development of a time projection chamber for the $\mu^+
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%\rightarrow e^+e^+e^-$ experiment}
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\title{A study of a new experiment to search for the $\mu^+
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\rightarrow e^+e^+e^-$ decay}
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%%\subtitle{The poster subtitle here}
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\author{Tran Hoai Nam}
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\address{Department of Physics, Graduate School of Science, Osaka University}
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\makeposter
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\section{Introduction}
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{\Large
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\begin{itemize}
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\item New physics beyond the Standard Model: the $\mu^+ \rightarrow e^+e^+e^-$
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decay is a forbidden process.
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\item Current status of the experiment: upper limit of the branching ratio is
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$1.0\times10^{-12}$ \cite{belgrade}.
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\end{itemize}
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}
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%It is known that in the current theoretical framework of particle physics, the
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%Standard Model, lepton flavor is conserved. Charged lepton flavor violation
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%(cFLV) processes that violates lepton flavor number are not allowed. However,
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%extensions of the Standard Model predict that cFLV might occur at the rate that
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%future experiments can reach\cite{kunorev}. Experimental observation of such
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%processes would provide a clear evidence for new physics beyond the Standard
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%Model.
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%
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%In this study, I am planning to develop a central tracking detector for an
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%experimental search for a
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%neutrino-less decay of muon, the $\mu^+ \rightarrow e^+e^+e^-$ decay, at the
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%MuSIC facility, Research Center for Nuclear Physics, Osaka University. In
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%the past, many experiments have been carried out in attempt to find evidence
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%for such a process. Among them, the most recent experiment was done at Paul
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%Sherrer Institute (PSI) in Switzerland. From the experiment, the upper limit (at
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%confidence level of 90\%) for the branching ratio $\mu^+ \rightarrow
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%e^+e^+e^-$ normalized to the normal muon decay of $1.0\times10^{-12}$ is
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%reported\cite{belgrade}.
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%In order to carry out the search for
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%Purpose of this research is to develop a central tracking detector for an
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%experimental
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%search for the $\mu^+ \rightarrow e^+e^+e^-$ decay at the MuSIC, Research Center
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%for Nuclear Physics (RCNP), Osaka University. The $\mu^+ \rightarrow e^+e^+e^-$
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%decay is a charged lepton flavor
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%violation (cFLV) process, which is forbidden process in the Standard Model.
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%However, various extensions of the Standard Model predict that cFLV might occur
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%at the rate that future experiments can reach. Current experimental upper limit
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%(at confidence level of 90\%) for the branching ratio $\mu^+ \rightarrow
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%e^+e^+e^-$ is $1.0 × 10−12$
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\section{Methods}
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{\Large
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In order to carry out the experiment, two important items
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are needed: a high-intensity muon beam; and a good tracking detector.
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}
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\subsection{The MuSIC facility}
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\begin{center}
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\includegraphics[width=27cm]{figs/music.eps}
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\caption{Schematic view of the MuSIC}
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\label{fig:schememusic}
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\end{center}
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%The goal of this experiment is to achieve a sensitivity of $1.0\times10^{-14}$,
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%which means two orders of magnitude improvement from the current limit. To carry
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%out a search for the $\mu^+ \rightarrow e^+e^+e^| $ process at such a
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%sensitivity, a highly intense muon source is needed because the number of muons
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%that would be usable for an experiment will determine the sensitivity. This high
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%intensity source will be available at the MuSIC (Muon Science Innovative
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%Channel), a newly installed beam line at RCNP (Research Center for Nuclear
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%Physics), Osaka University.
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{\Large
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\begin{itemize}
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\item MuSIC (\textbf{Mu}on \textbf{S}cience \textbf{I}nnovative
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\textbf{C}hannel): a
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newly installed beam line at RCNP, Osaka University.
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\item The world most intense muon beam: $10^9$ muons/sec with 1 $\mu$A proton
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beam current (400 MeV in energy)
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\item Purpose: particle physics, nuclear physics, material science, \ldots
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\item DC beam: important characteristic for the $\mu^+ \rightarrow e^+e^+e^- $
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experiment, because it reduces accidental background.
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\end{itemize}
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}
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\columnbreak
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\subsection{The time projection chamber (TPC)}
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{\Large
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\begin{itemize}
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\item Use for tracking charged particles ($e^- $ and $e^+$) which are products
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of the $\mu^+ \rightarrow e^+e^+e^- $ event. The event signatures are: a)
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$\Sigma p = 0$; b) $\Sigma E = m_\mu$; c) same vertex; d) same time.
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\item GEM-TPC (figure below) is a good candidate, because:
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\begin{itemize}
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\item Event vertex can be reconstructed,
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\item Can work at high count rate while maintaining high resolution
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\cite{fabbi32}
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\end{itemize}
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% \item Advantages of GEM-TPC:
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\end{itemize}
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}
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\begin{center}
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\includegraphics[width=25cm]{figs/gemtpc.eps}
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\caption{Illustration of a GEM-TPC (a); and GEM structure (b).}
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\label{fig:gemtpc}
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\end{center}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\section{Plan\& Status}
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\subsection{Plan}
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{\Large
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\noindent \textbf{The first step is simulation study:}
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\begin{itemize}
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% \setlength{\itemsep}{0pt}
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\item Event generator
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\item Geant4 simulation for the MuSIC beam line
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\item Transportation of charged particles in the detector
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% by Garfield simulation toolkit(\url{http://garfield.web.cern.ch/garfield/})
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\textcolor{red}{$\rightarrow$} results will be used to design a prototype GEM-TPC.
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\end{itemize}
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%\vspace{-0.3cm}
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\noindent \textbf{Next step is experiments:}
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\begin{itemize}
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\item A prototype TPC (20 cm $\times$ 10 cm) will be constructed,
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\item Experiments to test its performance and optimize
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\end{itemize}
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}
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\columnbreak
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\subsection{Status}
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{\Large
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Currently, I have finished part of simulation study, that includes:
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\begin{itemize}
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\item An event generator to simulate $\mu^+ \rightarrow e^+e^+e^-$ events
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based on different models. From this simulation, acceptance of the detector
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can be predicted:
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\begin{center}
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\includegraphics[width=20cm]{figs/acceptance.eps}
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\caption{Acceptance of the detector as a function of the momentum cut}
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\label{fig:acceptance}
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\end{center}
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\item Simple model of the TPC to register the $\mu^+ \rightarrow e^+e^+e^-$
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events, and an event reconstruction program has been developed:
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\begin{center}
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\includegraphics[width=20cm]{figs/tpc.eps}
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\caption{Simple model of the TPC}
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\label{fig:model}
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\end{center}
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\end{itemize}
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Also, the prototype construction is subject to be funded.
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}
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%\centerline{\includegraphics[width=\linewidth]{figs/w81s_4poster.ps}}
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%\centerline{ \textbf{Figure 5}: \textit{Results for field W81s (same format as
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%Fig.~4).}}
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%
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%\vspace*{20mm}
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%%% Try to align numbers; not perfect but works.
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%\def\0{\hbox{\phantom{\footnotesize\rm 1}}}%. \def\tabcolsep{4mm}
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%\begin{center} \begin{tabular}{cccccc} \hline field & \# ON & \# OFF & \don
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% & \doff & soma \\
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% %% & (\#) & (\#) & (\um) & (\um) & (\um) \\
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% \hline W81s & 65 & 70 & $116 \pm 20$ \um & $130 \pm 25$ \um & \09
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% \um\\ M623 & 74 & 82 & $100 \pm 13$ \um & $\090 \pm 15$ \um & 15 \um
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% \\ \hline \end{tabular} \end{center}
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%
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%\vspace*{5mm}
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%
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%\textbf{Table~1}: \textit{Best-fit parameters of the \dmin model to the two
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%datasets. \don\ and \doff: mean $\pm$ s.d. of homotypic exclusion zones; soma:
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%diameter of heterotypic exclusion zone.}
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%
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\vspace*{-1cm}
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\begin{thebibliography}{99}
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\setlength{\itemsep}{-2mm}
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% \bibitem{kunorev}Y. Kuno and Y. Okada, Review of Modern Physics
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% (2001) 73 151-202
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\bibitem{belgrade}U. Belgrade et al., Nuclear Physics B (1988) 299
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1-6
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\bibitem{fabbi32}L. Fabbietti et al., Nuclear Instruments and Methods in
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Physics Research A 628 (2011) 204-208
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% \bibitem{music}The MuSIC collaboration, The MuSIC Project under The
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% Center of Excellence of Sub Atomic Physics (not published)
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\end{thebibliography}
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\end{document}
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% LocalWords: RGCs
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