%--the poster is one beamer frame, so we have to start with:
\begin{frame}[t]
	%--to seperate the poster in columns we can use the columns environment
	\begin{columns}[t] % the [t] options aligns the columns content at the top
		\begin{column}{\onecolwid}% the right size for a 3-column layout
			%--abstract block--------------------------------------------------------
			\begin{alertblock}{Introduction}
				\textcolor{red}{Charged lepton flavor violation (cLFV)} has yet to be
				observed and is known to be sensitive to new physics beyond the
				Standard Model (SM).
				Various extensions of the SM predicts that cLFV occurs at some detectable
				branching ratio. Therefore, from experimental point of view, it is
				very attractive to search for cLFV with more powerful beams and better
				detection techniques.

				Among the cLFV processes, $\mu-e$ conversion, a coherent neutrino-less
				conversion of muon to electron in the presence of a nucleus: \muecaz,
				is our interest. We have proposed a new search for $\mu -e$ conversion
				at J-PARC, the E21 experiment - \textcolor{red}{COMET}(
				\textcolor{red}{COherent Muon to Electron Transition}). The single
				event sensitivity (SES) of the COMET will be
				\textcolor{red}{$2.6\times10^{-17}$}, which is
				10,000
				times better than that of the current experimental limit 
				set by SINDRUM II at \textcolor{red}{$7\times10^{-13}$}.

			\end{alertblock}

			\begin{alertblock}{Staging approach of the COMET}
				In order to realize the COMET experiment, a two-stage approach has been
				taken. The first stage, \textcolor{red}{COMET Phase-I} has two major
				goals:
				\begin{enumerate}
					\item \textcolor{red}{Search for $\mu-e$ conversion}: we aim at an
						intermediate SES of \textcolor{red}{$3\times10^{-15}$}, which is an
						improvement of a factor of 100 compares to SINDRUM II. 
					\item \textcolor{red}{Background measurements} for full COMET: make
						direct measurement of the proton beam extinction and other
						potential background sources, using the actual COMET beam line.  
				\end{enumerate}

				\begin{figure}[h!]
					\begin{center}
						\includegraphics[width=0.96\onecolwid]{../figs/comet/comet_phase_1}
					\end{center}
					\caption{Schematic layout of the COMET}
					\label{fig:cometscheme}
				\end{figure}

				Layout of the COMET experiment at Hadron Hall, J-PARC is shown in the
				Fig~\ref{fig:cometbeamline}. For the COMET Phase-I, we will construct
				the first \textcolor{red}{90 degrees} of the muon beam line before
				extracting to the experimental area. 

				The COMET Phase-I \textcolor{red}{funding has been approved} by KEK.
				This will cover
				experimental hall and beam line construction.  The construction is
				expected to finish in 2015, then data taking would start around
				2016.
				\begin{figure}[h!]
					\begin{center}
						\includegraphics[width=0.940\onecolwid]{../figs/comet/comet_in_hadron_hall}
					\end{center}
					\vskip1.6ex
					\caption{COMET beam line in the Hadron Hall extension plan}
					\label{fig:cometbeamline}
				\end{figure}
			\end{alertblock}
		\end{column}
		%===rightcolumn=================================================================
		% here the the middle and right column are put into one big column, this allows
		% to change between 2 and 3 column style
		%\begin{column}{0.60\paperwidth} %thats the big right column
		%\begin{block}{}
		%===two right columns===========================================================
		% we have to give the total width for the column wich is equal to the sum of
		% two colums and the space between them, this is needed to make shure the two
		% cols take all the space of the 'mother' column 
		%\begin{columns}[t,totalwidth=0.60\paperwidth]
		% and then we put in two normal sized columns
		\begin{column}{\twocolwid}
			\begin{figure}[h!]
				\begin{center}
					\includegraphics[width=0.99\twocolwid]{../figs/comet/comet_phase1_layout.png}
				\end{center}
				\caption{Concept of the COMET Phase-I}
				\label{fig:phase1}
			\end{figure}
			\vskip-2ex
			\begin{columns}[t,totalwidth=\twocolwid]
				\begin{column}{\onecolwid}
					\begin{alertblock}{Proton beam}
						COMET Phase-I will use an \textcolor{red}{8 GeV, 0.4 $\mu$A} ($2.5 \times 10^{12}$
						protons/sec), slowly extracted proton
						beam from the J-PARC main ring (MR). One proposed configuration for
						the bunch structure of the proton beam is shown in
						Fig~\ref{fig:pbeam}.
						\begin{figure}[]
							\includegraphics[width=0.65\onecolwid]{../figs/comet/comet_pbeam_config}
							\vskip-1.5ex
							\caption{COMET proton beam acceleration bunch configuration}
							\label{fig:pbeam}
						\end{figure}
					\end{alertblock}
					\begin{alertblock}{Muon transportation}
						The muon beam line of COMET Phase-I includes the pion capture
						section and the muon transport section up to the end of first
						$90^o$ bend. The field in the superconducting pion capture solenoid 
						is 5 T. Pions and
						muons - produced when pions decay in flight - goes to
						a matching section, before going to the transport solenoid with
						a 3 T field. \textcolor{red}{A prototype of this system has been
						built and operated successfully at Osaka University.}

						Negative muons  are selected by a dipole field, which 
						is created by an additional winding on top of the solenoid
						windings. A collimator is placed in front of the detector section
						to eliminate high momentum muons (and survival pions).
						\begin{figure}[]
							\includegraphics[width=0.70\onecolwid]{../figs/comet/mu_stop_phase1}
							\vskip-1.5ex
							\caption{Momentum distribution of muons approaching the target
							(open histogram) and those stopped by it (red)}
							\label{fig:mustop}
						\end{figure}
					\end{alertblock}
					\begin{alertblock}{Schedule}
						\begin{figure}[!h]
							\includegraphics[width=0.95\onecolwid]{../figs/comet/comet_phase1_sched}
							%\caption{Technical driven schedule of COMET Phase-I}
							\label{fig:sched}
						\end{figure}
					\end{alertblock}
				\end{column}

				\begin{column}{\onecolwid}
					\begin{alertblock}{Detectors for COMET Phase-I}
						There will be two detectors for two goals of COMET Phase-I: physics
						measurements and background measurements. 
						\begin{enumerate}
							\item \textcolor{red}{$\mu-e$ conversion search:}
								There are two candidates for the detector for the
								search. \textcolor{red}{Baseline detector is a cylindrical
								drift chamber (CDC)}, shown in the detector section in
								Fig~\ref{fig:phase1}. 
								The CDC is chosen because it would help reducing background rate
								and hit rate.  The alternative option is using the same detector
								for background measurements: a tranverse tracker, which is
								decribed below.

								The CDC is placed inside a magnetic field of 1 - 1.5 T. It is
								tuned to accept particles with momentum larger than 70 MeV/c.
								Segmented triger hodoscope is located before the drift chamber,
								provides timing signal and reduces protons hit rate on the
								chamber. In order to reach the goal SES, energy resolution
								requirement for the CDC is \textcolor{red}{1.5 MeV at 105 MeV}.
								%\vskip-1ex
								\begin{figure}[!h]
									\includegraphics[width=0.90\onecolwid]{../figs/comet/comet_signal}
									\vskip-1ex
									\caption{Signal of $\mu-e$ conversion, electron with
									momentum of about 105 MeV/c (red); and background from electron
									from muon decay in orbit (blue).}
									\label{fig:signal}
								\end{figure}

							\item \textcolor{red}{Background measurements:}
								A \textcolor{red}{tranverse tracker} will be used. It consists
								of a solenoid magnet, 0.8
								- 1 T, 5 straw tube tracker layers and a crystal calorimeter.
								This is regarded as a final \textcolor{red}{prototype for
								Phase-II detector}.
								\begin{figure}[!h]
									\includegraphics[width=0.90\onecolwid]{../figs/comet/comet_p1_det_bg}
									\vskip-1ex
									\caption{Concept of the detector for background measurements}
									\label{fig:phys_det}
								\end{figure}
						\end{enumerate}
						A lot of detector R\&D  activities are ongoing: ECAL
						with GSO/LYSO crystals and APD readout; prototype of straw tube
						tracker; front end electronic board; calculation and wire
						chamber test for CDC; \ldots
					\end{alertblock}
				\end{column}
			\end{columns}

		%\begin{column}{\onecolwid}
			%\vskip2ex
			%\begin{block}{References}
				%\small{\begin{thebibliography}{99}
						%\bibitem{cdr} The COMET Collaboration, ``Conceptual Design Report for
						%Experimental Search for Lepton Flavor Violating $\mu^--e^-$ 
						%Conversion at
						%Sensitivity of $10^{-16}$ with a Slow-Extracted Bunched Proton Beam
						%(COMET)'', KEK-2009-10 
						%\bibitem{loi} The COMET Collaboration, ``Letter of Intent for Phase-I
							%of the COMET Experiment at J-PARC'', J-PARC-2012-3
					%\end{thebibliography}}
				%\end{block}
			%\end{column}

				\end{column}
				\end{columns}
			\end{frame}
