\documentclass{cernyrep}
\begin{document}
\title{Plans for super-beams in Japan}
\author{Takuya Hasegawa}
\institute{High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan}
\maketitle

\begin{abstract}
In Japan, as the first experiment utilizes J-PARC (Japan Proton Accelerator Research Complex) neutrino facility, 
T2K (Tokai to Kamioka Long Baseline Neutrino Experiment) starts operation. 
T2K is supposed to give critical information, which guides the future direction of the neutrino physics. 
Possible new generation discovery experiment based on T2K outcome is discussed. 
Especially, description of J-PARC neutrino beam upgrade plan and discussion on far detector options 
to maximize potential of the research are focused. European participation and CERN commitment on Japanese accelerator
based neutrino experiment is also reported.  
\end{abstract}

\section{J-PARC and Main Ring Synchrotron}

J-PARC (Figure~\ref{fig:J-PARC}) is a KEK-JAEA joint facility for MW-class high intensity proton accelerator.
It provides unprecedented high flux of various secondary particles, such as neutrons, muons, pions, kaons, and neutrinos,
which are utilized for elementary particle physics and material and life science.
%
\begin{figure}[htb]
\begin{center}
\includegraphics[width=9cm,angle=-90]{J-PARC}
\caption{J-PARC accelerator and experimental facility}
\label{fig:J-PARC}
\end{center}
\end{figure}
% 
%allows experiment  with hiprovide various secondary beams 
%
%First of all thank you for inviting me to this important workshop.
%I am Takuya Hasegawa from KEK.
%Today, I would like to disucuss "Plans for super-beams in Japan"
%
%Contents are, First I will explain J-PARC (Japan Protn Accelerator Research Ccomplex) accelerator and neutrino bam facility,
%and T2K as a first experiment utilizes J-PARC neutrino beam. Then moving to the main subject, possible future discovery experiment
%with J-PARC neutrino beam, including neutrino beam upgrade plan (KEK roadmap) and Far Detector options.
%then I will summarieze the discussion with showing accelerator based neutrino @roject in Japan.
%Finaly I will mesion the shings what we think important for accelerator based neutrino project in Japan.

In the accelerator complex, H$^{-}$ ions are accelerated to 181~MeV with LINAC, fed
into Rapid Cycling Synchrotron (RCS) with stripping out electrons and are accelerated to 3~GeV. At final stage, proton beam goes into Main Ring Synchrotron (MR) 
and accelerated to 30~GeV. For the neutrino experiment, accelerated protons are
kicked inward to neutrino beam facility by single turn with fast extraction devices. 
Main characteristics of MR is described in Figure~\ref{fig:MR}.
%
%The J-PARC accelerator complex which includes
%the 180~MeV LINAC, the 3~GeV Rapid Cycling Synchrotron (RCS) and the
%30-50~GeV Main Ring Synchrotron (MR) is planned to be commissioned in 2008.
%The J-PARC neutrino beam facility, under
%construction for the T2K experiment, is foreseen to begin
%operation in 2009.  
%
%
%located west part of straight section of accelerator.
%Beam is guided by magnet to Target station and neutrino is going to the west.
%
%
%Figure~\ref{fig:J-PARC} 
%Figure~\ref{fig:MR} 
%Figure~\ref{fig:neutrino} 
%Figure~\ref{fig:first} 
%Figure~\ref{fig:neutrino2} 
%Figure~\ref{fig:T2K} 
%Figure~\ref{fig:SK} 
%Figure~\ref{fig:ND280} 
%Figure~\ref{fig:ND280status} 
%Figure~\ref{fig:collaboration} 
%Figure~\ref{fig:participants} 
%Figure~\ref{fig:potential} 
%Figure~\ref{fig:roadmap} 
%Figure~\ref{fig:angle} 
%Figure~\ref{fig:spectrum} 
%
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{J-PARC}
%\caption{J-PARC Accelerator and Experimental Facility}
%\label{fig:J-PARC}
%\end{center}
%\end{figure}
%
\begin{figure}[htb]
\begin{center}
\includegraphics[width=9cm,angle=-90]{MR2}
\caption{Overview of MR}
\label{fig:MR}
\end{center}
\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{neutrino}
%\caption{Neutrino Beam Facility}
%\label{fig:neutrino}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{first}
%\caption{Confirmation of Neutrino Procuctioin with Associated muon}
%\label{fig:first}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{neutrino2}
%\caption{Confirmation of Basic Functionality of Neutrino Beam Facility}
%\label{fig:neutrino2}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{T2K}
%\caption{T2K as the first experiment with J-PARC Nenutrino Beam}
%\label{fig:T2K}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{SK}
%\caption{Far main detector, SK}
%\label{fig:SK}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{ND280}
%\caption{Near Detector for T2K (ND280)}
%\label{fig:ND280}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{ND280status}
%\caption{Status of ND280 as of Oct. 2010}
%\label{fig:ND280status}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{collaboration}
%\caption{T2K collaboratioin}
%\label{fig:collaboration}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{participants}
%\caption{Participants for T2K}
%\label{fig:participants}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{potential}
%\caption{T2K Dicovery Potential on $\nu_\mu\to\nu_e$ as a Function of Integrated Power}
%\label{fig:potential}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{roadmap}
%\caption{KEK Roadmap}
%\label{fig:roadmap}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{angle}
%\caption{Neutrino Flux for various Off-Axis Angle}
%\label{fig:angle}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{spectrum}
%\caption{$\mu_\mu\to\nu_e$ Oscillation Probability as a Function of Energy/Baseline for various $\delta$}
%\label{fig:spectrum}
%\end{center}
%\end{figure}
%
%Figure~\ref{fig:scenario} 
%Figure~\ref{fig:scenario1} 
%Figure~\ref{fig:scenario2} 
%Figure~\ref{fig:scenario3} 
%Figure~\ref{fig:comp} 
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{scenario}
%\caption{Three possible scenarios studied at NP08 workshop}
%\label{fig:scenario}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{scenario1}
%\caption{Scenario 1: J-PARC to Okinoshima }
%\label{fig:scenario1}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{scenario2}
%\caption{Scenario 2: J-PARC to Kamioka }
%\label{fig:scenario2}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{scenario3}
%\caption{Scenario 3: J-PARC to Kamioka/Korea}
%\label{fig:scenario3}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{comp}
%\caption{Healthy scientific competicion and cooperation between Asia, EU and USA}
%\label{fig:comp}
%\end{center}
%\end{figure}
%5
\section{J-PARC neutrino beam facility}
%
%located west part of straight section of accelerator.
%Beam is guided by magnet to Target station and neutrino is going to the west.
%
The proton beam from MR run through J-PARC neutrino beam facility and producing
intense muon neutrinos toward the west direction. 
J-PARC neutrino beam facility is composed of following 
parts with their functionalities (Figure~\ref{fig:neutrino}).
%
\begin{figure}[htb]
\begin{center}
\includegraphics[width=9cm,angle=-90]{neutrino}
\caption{J-PARC neutrino beam facility}
\label{fig:neutrino}
\end{center}
\end{figure}
\begin{itemize}
\item Preparation section: Match the beam optics to the arc section.
\item Arc section: Bend the beam $\sim$90$^\circ$ toward the west direction with superconducting combined function magnet.
\item Final focus section: Match the beam optics to target both in position and in profile. Level of mm control is necessary which
corresponds to 1~mrad
$\nu$ direction difference, also not to destroy target.
\item Graphite target and horn magnet: Produce intense secondary $\pi$'s and focus them to the west direction. (3~horns system 
with 320~kA pulse operation) 
\item Muon monitor: Monitor $\mu$ direction ($=$ $\nu$ direction), pulse to pulse, with measuring center of muon profile. 
\item  On-axis neutrino monitor (INGRID): Monitor $\nu$ direction and intensity.
\end{itemize}
This facility is designed to be tolerable up to $\sim$2~MW beam power. The limitation is due to temperature rise and thermal shock
for the components such as  Al horn, graphite target, and Ti vacuum window.
Since everywhere suffers from high radiation, careful treatment of radioactive water and air ($\sim$10~GBq/3weeks) is required. 
Moreover, maintenance scenario of radio active components has to be seriously planned.
%
%
%
%
%Extracted beam from MR is guided by magnets toward  in neutrion beam facility and
%bend aboutn 90$\circ$ to west, then hit the carbon target.
%Emerged high flux pions are focused by set of horn magnet and decay decay tunnel
%
%the proton beam from the MR  will be colliede with a target to produce intense bursts
%of pions. these pions are collected and focussed forward by a magnet system consisting of 3 horns(selecting
%one charge, usually positive, in the process) into a decay volume.
%the resulting pions decays produce beams of numu and muons, and the decay 
%volume length is adjusted so that most of the pions but as few of the muons as possible decay before they reach
%the beam dump at the end, 
%
%what is the right direction to aim the beam?
%a key element of the design of the T2K facility is that the neutrino beam is very carefully pointed so that the baem
%axis actually misses superkamokande. this, rather surprisingnly, actually results in a 
%considerable improvement in the quality of the beam for the nue appearance experiment.
%This arises from the kinematics of pi decay, which result in an enhancement in 
%the neutrino flux produced over a very narrow range of energies which depend on the
%exact off-asid angle(see fig) if the angle is carefully sselected this narrow
%peak can be put exactly on the oscillationmaximum at the far detector.
%this has three major advantages over a conventional on-axis beam.
%firstly, the off-sxis neutrino flux at the desired energy'(oscillation maximum) is actually  higher
%than on-axis. secondly, there are fewer high-energy neutrinos, which do not contribute to the appearance signal
%but do contribute to its backgrounds, in particular through
%the neutral current production of pi0's,. thirdly the background due to the intrinsic
%contamination of the beam nue is actually less at the off-axiss position due to the
%different kinematics of the decays that lead ot nue.
%
%
%The off-axis position therefore has gread advantages, however the very kinematics that gives
%a useful selecton in energy measn that the characteristics of the beam change rapidly
%with angle. Our detectors at 280m are near enough to the beanline that 
%it sees the beamline over an appreciable range of angles, so it seems a different neutrino
%spectrum than superkamiokande, this "near/far" effect needs to be corrected for
%to extrapolate a measurement of the neutrino spectrum at J-PARC to the expected
%spectrum at Kamioka, which requires a detailed understanding of the kinematics of
%the pions in the beam. the relavant pion(and kaon)production cross sections are
%being measured in a dedicated experiment at CERN(NA61), without which T2K's precision would be limited by this effect.
%
%Figure~\ref{fig:neutrino} shows major component of the neutrino beam facility.
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{neutrino}
%\caption{Neutrino Beam Facility}
%\label{fig:neutrino}
%\end{center}
%\end{figure}
%
%Its major functionality are,
%\begin{itemize}
%\item Preparation section: matching beam optics to arc section
%\item Arc section: bending the beam $\sim$90$^\circ$ to SK with superconducting combined function magnet
%\item Final focus section: matching beam optics to target�iposition and profile, level of mm control is necessary which correspond to 1 $mrad$
%$\nu$ direction, also not to destroy target�j
%\item Graphite Target and Horn Magnet: produce intense secondary $\pi$ and focus them to SK (3horn system with 320 $kA$ pulse operation) 
%\item  Muon Monitor: monitor $\mu$ direction ($=$ $\nu$ direction) pulse to pulse with measuring center of muon profile 
%\item  On Axis Neutrino Monitor(INGRID): monitor $\nu$ direction and intensity
%\end{itemize}
%
%This facility is designed to be tolerable up to $\sim$2~MW beam power. The limitation is due to temperature rise and thermal shock
%for the component such as  Al Horn, Graphite Target, and Ti Vacuum Window.
%Since everywhere high radiation, careful treatment of radioactive water and air ($\sim$10~GBq/3weeks)is necessary. 
%Moreover maintenance scenario of radio active beam facility components is necessary.
%
%\section{Commissioning of Neutrino Beam Facility}

On 23rd April 2009, commissioning of the facility started with the real proton beam which was delivered by MR. 
The very first shot of the proton beam, after all the beam line magnet turned on, steered into target station and
muon monitor clearly indicated production of intense muons which certified associated neutrino production.
After 9 shots of tuning, the beam is centered on the target.
%
%
%was steered around the beam line and into target and producing a detectable signal of muon 
%
%J-PARC neutrino beam facility started its operation in April 2009.
%Brief history of commissioning is,
%\begin{itemize}
%\item 23-April: Neutrino facility beam commissioning started. At 19:09 Turned on superconducting magnet and proton beam reached target region.
%Neutrino production was confirmed by associated muon signal.
%\item 24-April: Proton beam was tuned to be target center with 9 shots after superconducting magnet turned on. Confirming pion focusing with horn magnet. 
%\item 28-April: Rehearsal for government inspection.
%\item 22-27 May: MR commissioning. Neutrino facility commissioning for Check of the functionality of the beam monitors, for Check of the response function of the magnets and for Fine tuning of the primary proton beam orbit/profile.
%\item 28-May: Approval of  the government inspection of the neutrino facility on radiation safety. 
%\end{itemize}
%
%slide 7,8 for figure
%
%\section{Neutrino Facility Commissioning Achievement}
%
%To avoid unnecessary activation of the Target Station, into which 2nd and 3rd Horn installation is foreseen, integrated proton power on target to be minimized. (single shot or at most 6sec cycle of 1.5-14.2$\times$10$^{11}$ $protons/pulse$)
With subsequent tuning and measurement, followings are achieved.
\begin{itemize}
\item Stability of the extraction beam orbit from MR is confirmed. It is tuned within 0.3~mm in position and 0.04~mrad in direction w.r.t. 
design orbit.
\item Functionality of the superconducting combined function magnet is confirmed.
\item Beam is lead to the target center without significant beam loss. Beam trajectory is tuned within 3~mm level accuracy w.r.t. design orbit.
\item Functionality of the beam monitors (beam position, beam profile, beam intensity and beam loss) are confirmed.
\item Response function of various magnets are measured.
\item Muon signal is observed which confirms neutrino production. (Muon direction corresponds to neutrino direction and muon yield corresponds to neutrino yield.)
\item The effect of pion focusing with horn magnet is confirmed. ($\times$2 which is consistent with horn configuration at that time.)
\item The information transfer from Tokai to Kamioka  on the absolute beam time information is confirmed.
\item J-PARC neutrino facility is approved by the government on radiation safety.
\end{itemize}
%as was shown in Figure~\ref{fig:first} and Figure~\ref{fig:neutrino2}.
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{first}
%\caption{Confirmation of Neutrino Procuctioin with Associated muon}
%\label{fig:first}
%\end{center}
%\end{figure}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{neutrino2}
%\caption{Confirmation of Basic Functionality of Neutrino Beam Facility}
%\label{fig:neutrino2}
%\end{center}
%\end{figure}
%%most of this equipment got its first beam test on 23rd april 2009, when the first
%5s%hots of the proton beam wer delivered from MR. We were extremely pleased
%when the very first shot of the proton beam was steered around the beamline
%and into the target facility and produced a detectable signal in the muon monitors.
%after just 9 shots the beam had been centered on the target, and subsequent measurements showed
%all installed elements to be working well. as of the time of this writing
%we are now engaging in th final installation and preparation fro 
The next running of the facility is foreseen from October 2009 with following MR intensity improvement.
Production data taking 
for neutrino experiment is foreseen to start in January 2010.

\section{T2K}
T2K~\cite{Itow:2001ee} is the first experiment with J-PARC neutrino beam. 
With the combination of unprecedented high intensity neutrino source and a well established neutrino detector, Super-Kamiokande (SK),
as a far main detector, T2K will seeks for  $\nu_\mu$ to $\nu_e$ conversion phenomenon and, as a consequence,
measures an finite value of one of the neutrino mixing angle, $\theta_{13}$, with an order of magnitude 
better sensitivity compared to the prior experiments
at an atmospheric neutrino anomaly regime.
T2K also conduct precision measurement of another neutrino mixing angle, $\theta_{23}$.
Moreover, something unexpected in neutrino physics may be revealed by T2K.

The baseline of 295~km and off-axis angle of  2.5$^\circ$ are optimized, 
%1) in order to maximize sensitivity, narrow band neutrino beam whose intensity maximum set to be first oscillation maximum.
1) to maximize neutrino flux at the neutrino energy of the first oscillation maximum, 
2) to avoid severe $\pi^0$ background originated from high energy neutrino interaction, and 
3) to tune neutrino energy range to be optimum for a water cherenkov detector (sub GeV energy region, low multiplicity and quasi elastic interaction dominant).

The properties of the produced neutrino beam are measured by a system of near detectors
at J-PARC which consists of two major parts, one is
on-axis neutrino monitor (INGRID) which 
monitors neutrino direction, intensity and its stability,  and the other is an assembly of detectors located 2.5$^\circ$ off-axis
direction as SK (ND280),
which measures not only neutrino flux as is expected at SK  but also  sub GeV neutrino interaction which gives important
information for neutrino oscillation analysis in T2K.
The most outer part of the ND280 is the UA1/NOMAD magnet,
which provides the magnetic field used to determine the momentum of charged particles originated from neutrino interaction.
Inside the magnet, Fine Grain Detector (FGD) which is an active neutrino target, Time Projection Chamber (TPC) which measures any charged particles 
emerged from neutrino interaction, $\pi^0$ detector (POD) which is optimized for measuring the rate of neutral current $\pi^0$ production, 
Electromagnetic Calorimeter (ECAL) which reconstructs any electromagnetic energy produced, and Side Muon Range Detector (SMRD)
which is instrumented in the magnet yokes to identify muons from neutrino interaction, are located.
The status of detectors as of October 2009 is  shown in Figure~\ref{fig:ND280status}.
\begin{figure}[htb]
\begin{center}
\includegraphics[width=9cm,angle=-90]{ND280status}
\caption{Status of the T2K near site neutrino detectors as of October 2009}
\label{fig:ND280status}
\end{center}
\end{figure}

As a first milestone, T2K 
is aiming for the first results in 2010
with 100~kw $\times$ 10$^7$~seconds integrated proton power on target
to unveil below
the CHOOZ experimental limit~\cite{Apollonio:1999ae} with $\nu_e$ appearance.

\section{European and CERN commitment on Japanese accelerator
based neutrino experiment}
European participation in Japanese accelerator based neutrino experiment
began at K2K (KEK to Kamioka Long Baseline Neutrino Experiment).
France, Italy, Poland, Russia, Spain and Switzerland joined this world first 
accelerator based long baseline neutrino experiment. 
When T2K project started, Germany and United Kingdom also participated. 
As of October 2009, T2K collaboration consists of 477 members from 62 institutes spread out 12 coutries.
Composition is, 240 (50.3$\%$) members from Europe, 84 (17.6$\%$) members from Japan, 77 (16.1$\%$) members from USA,
68 (14.3$\%$) members from Canada and 8 (1.7$\%$) members from South Korea, as shown in Figure~\ref{fig:participants}.
% 84(17.6)$\%$ from Japan  77(16.1)$\%$ from USA
% 68(14.3)$\%$ from Canada 8(1.7%)$\%$ from South Korea.
%Figure~\ref{fig:collaboration}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{collaboration}
%\caption{T2K collaboratioin}
%\label{fig:collaboration}
%\end{center}
%\end{figure}
%
\begin{figure}[htb]
\begin{center}
\includegraphics[width=6cm,angle=-90]{participants}
\caption{Participants for T2K}
\label{fig:participants}
\end{center}
\end{figure}
%
%
%\section{?CERN Support to T2K(RE13)}
%
%

T2K is registered as Recognized Experiment at CERN (RE13) and CERN
extensively supports T2K.
Followings are the list of CERN support for T2K.
\begin{itemize}
\item CERN experiment NA61: This experiment is indispensable part of T2K to understand neutrino flux for the experiment.
\item CERN test beam for detectors.
\item Donation of UA1/NOMAD magnet.
\item Micromegas production and its test conducted by CERN TS/DEM group.
\item Various technical, administrative support on detector preparation, especially for UA1/NOMAD magnet related issues.
\item Infrastructure for detector preparation.
\item CERN-KEK cooperation on super conducting magnet for neutrino beam line.
\end{itemize}
KEK feels grateful to CERN for all the aspect of support provided by CERN.
%
%\section{KEK feels grateful to CERN ?}
%Massage from Toru Ogitsu and Akira Yamamoto
%
%For the T2K primary beam line construction;
%
%Procurement of many components 
%for superconducting combined function 
%magnets (2.6T + 19T/m, 3.3m long)x28
%chases large scale procurement for LHC, 
%with the same price!
%
%We would thank CERN  for the kindest 
%cooperation given during the cryostat 
%design and fabrication for the JPARC 
%Neutrino SC beam line, using much 
%experience integrated with the LHC 
%accelerator construction and the 
%KEK-CERN technical collaboration on LHC.
%
%
%
%
\section{New generation accelerator based neutrino experiment in Japan}
%Primary Motivation of T2K
%Primary Motivation of T2K is 
%Discover $\nu_\mu\to\nu_e$ conversion phenomenon 
%prior to any other experiment in the world
%and, as a consequence,
%Conclude Lepton Flavor Mixing Structure.
The primary motivation of T2K
%\footnote{\setlength{\baselineskip}{4mm}T2K is a name for 
%the approved Tokai to Kamioka experiment using Super-Kamiokande as far detector.
%New investigations or performance upgrades beyond this approved phase will presumably
%have a different name.} 
is to improve the sensitivity to the $\nu_{\mu} \rightarrow \nu_e$ conversion phenomenon 
in the atmospheric regime.
%
% by about an order of magnitude in the mixing
%angle $\sin^2 2\theta_{13}$ compared to the CHOOZ experimental limit~\cite{Apollonio:1999ae}.
%The discovery of a non-vanishing  $\theta_{13}$ angle would
%ascertain the $3\times 3$ nature of the lepton flavor mixing matrix.
%The measurements in T2K might
%indicate that the $\theta_{13}$ angle is in a region where the 
%simultaneous determination of neutrino 
%mass hierarchy and the CP violating phase becomes possible.
%prior to any other experiment in the world
%and, as a consequence,
%Conclude Lepton Flavor Mixing Structure.
%
%we might fnd that we were seeing special numbers  theta13 is very close to zero  or theta 23 very close to mmaximal
%which should be poointing to some underlying symmetry which a more fundamental theory musl explain.
%
%
%
%\subsection{T2K Proposal Accepted by J-PARC PAC}
%
%T2K Proposal Accepted by J-PARC PAC is 
%"We request total integrated beam power larger than 0.75~MW~$\times$~15,000~h at any proton energies between 30 and 50~GeV.�g
%here 3,000~h(about 10$^7$~sec.) corresponds to 4~months which is expected running period of T2K per year.
%
%
The final goal for T2K 
is to accumulate an integrated proton power on target of $0.75$~MW$\times5\times 10^7$ seconds.
As is shown in Figure~\ref{fig:potential},
%\subsection{T2K Discovery Potential on $\nu_\mu\to\nu_e$ as a Function of Integrated Power}
%
\begin{figure}[htb]
\begin{center}
\includegraphics[width=9cm,angle=-90]{potential}
\caption{T2K dicovery potential on $\nu_\mu\to\nu_e$ as a function of integrated proton power on target}
\label{fig:potential}
\end{center}
\end{figure}
%$
%$Figure~\ref{fig:potential}
%$Fig. shows T2K Discovery Potential on $\nu_\mu\to\nu_e$ as a Function of Integrated Power.
%$With 100~kW~$\times$~10$^7$~sec. integrated proton powers on target, which is aimed to be accumulated in 2010,
%$we will investigate below CHOOZ limit. With 1 to 2~MW~$\times$~10$^7$~sec. discovery potential reaches
%$0.05-0.03 in terms of  sin$^2$2$\theta_{13}$. And with 3.75~MW~$\times$~10$^7$~sec. we will complete T2K.
%$
%$As you see,
%ntegrated power of 1 to 2~MW~$\times$~10$^7$ seconds
%is a turning point to decide Next Project utilizing J-PARC Neutrino Beam.
%
within a few years of run, critical information,
which will guide the future direction of the neutrino physics, 
will be obtained based on the data corresponding to about 
%$1\div2$~MW 
1 to 2~MW$\times$10$^7$ seconds integrated proton power on target 
(roughly corresponding to a 3$\sigma$ discovery at 
sin$^2$2$\theta$$_{13}$$>$ 0.05 and 0.03, respectively). 
%
%\subsection{Future Investment for the "Discovery" in $\nu$ Physics}
%
%
%It is well documented in the literature (see e.g. Refs.~\cite{Burguet-Castell:2001ez,Minakata:2001qm,Barger:2001yr})
%that the most challenging task for next generation 
%long baseline experiments is to unfold the unknown oscillation 
%parameters $\sin^22\theta_{13}$, $\delta_{CP}$ and mass hierarchy, $\rm sgn(\Delta m^2_{31})$,
%and from the measurement of the energy dependence of the oscillation signal to
%resolve the so-called problems of ``correlations'' and ``degeneracies''.
%

If a significant $\nu_\mu\to\nu_e$ coversion signal were to be observed at T2K, an immediate
step forward to a next generation experiment aimed at the discovery of CP violation
in the lepton sector would be recommended with high priority.
%
%In case ovserving significant $\nu_e$ signal,
%Future Investment for the "Discovery" in $\nu$ Physics is definitely, given to 
%Proceed Immediately to CP Violation Discovery
%For this purpose, we must
%\begin{itemize} 
%\item MUST: Improve $\nu $Beam Intensity
%\item MUST: Improve the Main(Far) Detector Quality In terms of
%\begin{itemize}                   
%\item Detector Technology
%\item Volume and 
%\item Baseline+Angle
%\end{itemize} 
%\end{itemize}  
%
%since the effets of delta in oscillations always appear multiplied by sin22theta13, findein ga non-zero value for
%theta 13 is a critical step in the campaign to measure delta
Compared with T2K experimental conditions, lepton sector CP violation discovery 
requires
\begin{itemize}
\item an improved J-PARC neutrino beam intensity;
%intensity increase, broader energy spectrum,
%possibly re-optimization of the focusing optics, ...);
\item an improved main far neutrino detector. 
%(by improvements we primarily mean increased
%signal reconstruction efficiency, better background separation, better
%energy resolution, ..., and not only its volume).
\end{itemize}
Detector improvements include
\begin{itemize}
\item detector technology;
\item its volume;
\item its baseline and off-axis angle with respect to the neutrino source.
\end{itemize}
%
Naturally, next generation far neutrino detectors for lepton sector CP violation discovery 
will be very massive and huge. As a consequence, 
the same detector will give us the rare and important opportunity to 
discover proton decay. 
A total research subject would be, to address a long standing puzzle of our physical world,
the ``Quest for the Origin of Matter Dominated Universe" (see e.g.~\cite{cpmatter}),
%
%
%
% with assuming non-equilibrium environment in the evolution of universe.
%
%
%As a consequence,
with exploration of 
%The``Quest for the Origin of Matter Dominated Universe" is a long standing puzzle of our physical world
%(see e.g.~\cite{cpmatter}).
%Answers to this question might come from further exploration of
\begin{itemize}
\item the Lepton Sector CP Violation by precise testing of the neutrino oscillation processes;
\begin{itemize}
\item measure precisely the CP phase in lepton sector ($\delta$)  and the mixing angle $\theta_{13}$;
\item examine matter effect in neutrino oscillation process and possibly
conclude the mass hierarchy of neutrinos.
\end{itemize}
\item Proton Decay:
\begin{itemize}
\item Search for p $\rightarrow$ $\nu$ K$^+$ and p $\rightarrow$ e $\pi^0$
in the life time range $10^{34}$ to $10^{35}$ years,
\end{itemize}
\end{itemize}
%next generation project 
%
with assuming non-equilibrium environment in the evolution of universe.
%
%will address 
%the``Quest for the Origin of Matter Dominated Universe"
%
%a long standing puzzle of our physical world
%the ``Quest for the Origin of Matter Dominated Universe" which is a long standing puzzle of our physical world
%(see e.g.~\cite{cpmatter}) with assuming non-equilibrium environment in the evolution of universe.
%.
%Answers to this question might come from further exploration of
%
%
% is a long standing puzzle of our physical world
%(see e.g.~\cite{cpmatter}).
%Answers to this question might come from further exploration of
%
%
%
%
%"J-PARC to Somewhere Long Baseline Neutrino Experiment and Nucleon Decay Experiment
%with Huge Volume Detector"
%
%
%
%
%Naturally, main neutrino detector 
%tends to be huge. As a consequence, main neutrino detector gives us rare and important opportunity to
% Discover Proton Decay, 
%
%Grand Unification of the strong, weak and electromagnetic interactions
%into a single unified gauge group is an extremely appealing idea~\cite{Pati:1973uk,Georgi:1974sy}  which has
%been vigorously pursued theoretically and experimentally for many years.
%The detection of proton or bound-neutron decays would represent its
%most direct experimental evidence.









%even in case no positive signal 
%there is interesting upgrade of experimnent with improved beam intensity and upgraded far detector
%At the $3\sigma$~C.L. the sensitivity of the T2K experiment is 0.02~\cite{Itow:2001ee}. Continuing to
%collect data at SK with an improved J-PARC neutrino beam for another 5~years 
%would improve the T2K sensitivity by a factor $\sim 2$. In comparison,
%our simulations indicate that a 20~kton LAr TPC is expected to perform
%better than this although the masses are comparable, 
%since the signal efficiency is higher than SK and the 
%NC background is assumed to be negligible contrary to SK. Even better, a 100~kton LAr
%TPC at Okinoshima would further improve the sensitivity by about a factor six compared
%to SK at Kamioka (or a factor 10 compared to T2K), 
%thanks to its bigger mass, increased cross-section at higher energies 
%and reduced off-axis angle, although the neutrino fluxes at the same off-axis angle would
%be reduced by a factor $\simeq 5$ because of the longer baseline.
%
Even in case that sin$^2$2$\theta$$_{13}$ is below T2K sensitivity, it is still worth while trying to improve 
J-PARC neutrino beam intensity and far detector performance to open the way to explore $\nu_\mu \to \nu_e$ conversion phenomenon
with by an order of magnitude better sensitivity~\cite{okinoshima}.
%
%
%
%
%
%
%\subsection{"Quest for the Origin of Matter Dominated Universe" as a
%research title in total}
%
%"Quest for the Origin of Matter Dominated Universe" is a research
%title in total 
%with 
%\begin{itemize}
%\item  Lepton Sector CP Violation
%with Search for CP violation in Neutrino Oscillation Process
%including Also examine mass hierarchy of neutrinos
%and examine matter effect in neutrino oscillation process
%\item Proton Decay like p$\to \nu$K and p$\to$e $\pi^0$
%\end{itemize}
%Non-equilibrium environment in the evolution of universe 
%in addition to two condition are famous saharof three condition
%to realize matter dominated universe.
%
%
%The``Quest for the Origin of Matter Dominated Universe" is a long standing puzzle of our physical world
%(see e.g.~\cite{cpmatter}).
%Answers to this question might come from further exploration of
%\begin{itemize}
%\item the Lepton Sector CP Violation by precise testing of the neutrino oscillation processes
%\begin{itemize}
%\item measure precisely the $\delta_{CP}$ and the mixing angle $\theta_{13}$;
%\item examine matter effect in neutrino oscillation process and possibly
%conclude the mass hierarchy of neutrinos.
%\end{itemize}
%\item Proton Decay:
%\begin{itemize}
%\item Search for p $\rightarrow$ $\nu$ K$^+$ and p $\rightarrow$ e $\pi^0$
%in the range $10^{34\div 35}$ years
%\end{itemize}
%\end{itemize}
%with assuming non-equilibrium environment in the evolution of universe.
%
%
%
%
%\subsection{project name as "J-PARC to Somewhere Long Baseline Neutrino Experiment and Nucleon Decay Experiment
%with Huge Volume Detector"}
%
%"J-PARC to Somewhere Long Baseline Neutrino Experiment and Nucleon Decay Experiment
%with Huge Volume Detector"
%
%\subsection{KEK Roadmap}

This direction of research is endorsed by KEK Roadmap defined in 2008,
in which J-PARC neutrino intensity improvement and R$\&$D to realize 
huge detector for neutrino and proton decay experiments
%
% Liquid Argon Time Projecton Chamber or water cherenkov detector 
are the two of the main subject.
KEK has started R$\&$D to realize huge liquid Argon time projection chamber.

%
%as shown in Figure~\ref{fig:roadmap}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{roadmap}
%\caption{KEK Roadmap}
%\label{fig:roadmap}
%\end{center}
%\end{figure}
%
\subsection{J-PARC neutrino beam upgrade plan}
%
%As for the neutrino beam intensity improvement, a realistic first 
%step power improvement scenario at 
%J-PARC Accelerator Complex has been recently analyzed and
%proposed (LINAC energy is recovered to be 400 MeV, h=1 operation at 
%RCS and 1.92 seconds repetition cycle operation
% at MR).
%
As for the neutrino beam intensity improvement,
MR power improvement scenario toward MW-class power frontier machine,
KEK Roadmap plan, is analyzed and proposed by the J-PARC accelerator team
as shown in Table~\ref{tab:roadmap}.
\begin{table}[htb]
\begin{center}
\caption{MR power improvement scenario toward MW-class power frontier machine (KEK Roadmap)}
\label{tab:roadmap}
\begin{tabular}{lcccc}
\hline\hline
             & Start Up & Next Step & \textbf{KEK Roadmap} & Ultimate    \\
\hline
 \textbf{Power} (MW)   & 0.1 & 0.45 & \textbf{1.66}  & ? \\
 \textbf{Energy} (GeV)   & 30 & 30 & \textbf{30}  &  \\
 \textbf{Rep. Cycle} (sec.)   & 3.5 & 3-2 & \textbf{1.92}  &  \\
 \textbf{No. of Bunches}   & 6 & 8 & \textbf{8}  &  \\
 \textbf{Particles/Bunch}   & 1.2$\times$10$^{13}$ & <4.1$\times$10$^{13}$ & \textbf{8.3$\times$10$^{13}$}  &  \\
 \textbf{Particles/Ring}   & 7.2$\times$10$^{13}$ & <3.3$\times$10$^{14}$ & \textbf{6.7$\times$10$^{14}$}  &  \\
 \textbf{LINAC} (MeV)   & 181 & 181 & \textbf{400}  &  \\
 \textbf{RCS$^{a}$}   & h=2 & h=2 or 1  & \textbf{h=1}  &  \\
\hline\hline
\multicolumn{3}{l}{$^{a}$ \footnotesize Harmonic number of RCS}
\end{tabular}
\end{center}
\end{table}
%
%\section{Item to be Modified from DAY1 toward High Intensity}

Items to be modified from start up  toward high intensity are listed as following.
\begin{itemize}
\item Number of bunches in MR should be increased from 6 to 8.
For this purpose, fast rise time extraction kicker magnet have to be prepared.
Its installation is foreseen in 2010 summer.
\item Repetition cycle of MR has to be improved from 3.5~seconds to 1.92~seconds.
For this purpose RF and magnet power supply improvement is necessary.
\item RCS operation wih harmonic number 1 has to be conducted. This is to make the beam bunch to be longer in time domain 
to decrease space charge effect.
For this purpose RF improvement is necessary.
When RCS is operated with harmonic number 2, beam is injected to MR with 2~bunches~$\times$~4~cycles. On the other hand,
when RCS is operated with harmonic number 1, beam is injected to MR with
single bunch with doubled number of protons $\times$~8~cycles.
\item  LINAC 400~MeV operation is required  to avoid severe space charge effect at RCS injection.
Construction of necessary component is already approved and started.
\end{itemize}

\subsection{Far detector options: How to approach Lepton Sector CP Violation}
%Depend on how to approach Lepton Sector CP Violation.
%
%Flavour and mass igenstate of neutrinos are related with three parameters $\theta_{ij}$ which descrives rotations between three neutrino states and
%and $\delta$ which controles the CP effect in lepton sector as Equation~(\ref{eq:a1}).
%\begin{equation}
%\begin{pmatrix}\nu_e \cr \nu_{\mu} \cr \nu_{\tau}\end{pmatrix}=
%\begin{pmatrix}C_{12}C_{13} & C_{13}S_{12} & e^{-i\delta}S_{13} \cr
%-S_{12}C_{23}-e^{-i\delta}C_{12}S_{13}S_{23} & C_{12}C_{23}-e^{i\delta}S_{12}S_{13}S_{23} & C_{13}S_{23} \cr
%-e^{i\delta}C_{12}S_{13}C_{23}+S_{12}S_{23} & -e^{i\delta}S_{12}S_{13}C_{23}-C_{12}S_{23} & C_{13}C_{23} \cr\end{pmatrix}
%\begin{pmatrix}\nu_1 \cr \nu_2 \cr \nu_3 \end{pmatrix}~.\label{eq:a1}
%\end{equation}
%where $C_{ij}=$cos$\theta_{ij}$ and $S_{ij}=$sin$\theta_{ij}$.
%
%
The effects of CP phase $\delta$ appear either 
%\begin{itemize}
%\item $\nu_e$ Appearance Energy Spectrum Shape
%\begin{itemize}
%\item Peak position and height for 1st, 2nd maximum and minimum
%\item Sensitive to all the non-vanishing $\delta$ including 180$^\circ$
%\item Could investigate CP phase with $\nu$ run only  
%\end{itemize}
%\item Difference between $\nu_e$ and $\bar{\nu}_e$ Behavior 
%\end{itemize}
%
%The effects of the CP phase $\delta_{CP}$ appear either
\begin{itemize}
\item as a difference between $\nu$ and $\bar{\nu}$ behaviors
(this method is sensitive to the $CP$-odd term which vanishes
for $\delta=0$ or 180$^\circ$);
\item in the energy spectrum shape of the appearance oscillated $\nu_e$ charged current events 
(sensitive to all the non-vanishing $\delta$ values including 180$^\circ$).
\end{itemize}
%
It should be noted that
if one precisely measures the $\nu_e$  appearance energy spectrum shape (peak position and height for 1st and 2nd oscillation maximum and minimum) 
with high resolution,
CP effect could be investigated with neutrino run only.
Antineutrino beam conditions are known to be more difficult than those
for neutrinos (lower beam flux due to leading charge effect in proton collisions
on target, small antineutrinos cross-section at low energy, etc.).
%
%, we
%concentrate on the possibility to precisely measure the 
%$\nu_e$ CC appearance energy spectrum shape with high resolution
%during a neutrino-only run.
%
%
%
%\subsection{Angle and Baseline}

Figure~\ref{fig:anglespectrum}~(left) shows neutrino flux for vaious off-axis angles.
\begin{figure}[htb]
\begin{center}
\includegraphics[width=6cm,angle=-90]{anglespectrum}
\caption{Neutrino flux for various off-axis angle (left) and Probability for $\nu_\mu\to\nu_e$ oscillations 
as a function of the E(GeV)/L(km) for various $\delta$. (right)}
\label{fig:anglespectrum}
\end{center}
\end{figure}
If one selects on-axis setting, 1) wide energy coverage is foreseen which is necessary to cover the 1st and 2nd maximum simultaneously,
and  
2) measurement suffers from severe $\pi^0$ background originated from high energy neutrino which requires the detector with high performance
discrimination ability between $\pi^0$ and electron.
On the other hand, if one selects off-axis setting, 1) requirement for $\pi^0$ background discrimination is soft, and  2) measurement 
is essentially counting experiment at the 1st oscillation maximum.
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{angle}
%\caption{Neutrino Flux for various Off-Axis Angle}
%\label{fig:angle}
%\end{center}
%\end{figure}
%
%
%Angle w.r.t On-Axis 
%\begin{itemize}
%\item On-Axis: Wide Energy Coverage, 
%      good forEnergy Spectrum Measurement
%       bad  for Control of $\pi^0$ Background
%\item Off-Axis: Narrow Energy Coverage, 
%       good for Control of $\pi^0$ Background
%       bad for Energy Spectrum Measurement
%       it is essentialy Counting Experiment
%\end{itemize}
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=6cm,angle=-90]{anglespectrum}
%\caption{a) Neutrino flux for various off-axis angle (left) b) Probability for $\nu_\mu\to\nu_e$ oscillations 
%as a function of the E(GeV)/L(km) for sin$^2$$\theta_{13}$=0.1 for varioust $\delta$.}
%\label{fig:anglespectrum}
%\end{center}
%\end{figure}
%
%
%
%
%
%\begin{figure}[htb]
%
%\begin{minipage}[b]{0.5\linewidth}
%
%\centering
%
%\includegraphics[width=3cm,angle=-90]{angle}
%\caption{Neutrino Flux for various Off-Axis Angle}
%\label{fig:angle}
%
%%\includegraphics[angle=0, width=9.0cm]{wbkg.eps}
%%\caption{\setlength{\baselineskip}{4mm}
%%Energy spectra at $\sin^2 2\theta_{13}$=0.03 case, but 
% $\delta_{CP}$ = 0$^{\circ}$ (top-left), 90$^{\circ}$ (right-top),
%180$^{\circ}$ (left-bottom), 270$^{\circ}$ (right-bottom) cases. 
%}
%\label{Fig:ES0mev}
%
%\end{minipage}
%\hspace{0.5cm}
%\begin{minipage}[b]{0.5\linewidth}
%
%\centering
%
%\includegraphics[width=3cm,angle=-90]{spectrum}
%\caption{$\mu_\mu\to\nu_e$ Oscillation Probability as a Function of Energy/Baseline for various $\delta$}
%\label{fig:spectrum}
%
%\includegraphics[angle=0, width=9.0cm]{sens_wbkg.eps}
%\caption{\setlength{\baselineskip}{4mm}
% Allowed regions in the perfect resolution case.
% Twelve allowed regions are overlaid for twelve true values,
% $\sin^2 2\theta_{13}$=0.1, 0.05, 0.02, and $\delta_{CP}$=0$^{\circ}$,
% 90$^{\circ}$, 180$^{\circ}$, 270$^{\circ}$, respectively.
%}
%\label{Fig:Allowed_0mev}
%
%
%\end{minipage}
%
%5\end{figure}
%
%
%5
%
%
%
%
%
%
%
%
%

Figure~\ref{fig:anglespectrum}~(right)
shows the oscillation probability as a function 
of the E(GeV)/ L(km).
% (neglecting for the moment matter effects). 
%In the plot, the mixing angle $\sin^2 2\theta_{13}$ was assumed to be 0.1.
If the distance between source and detector is fixed, the curves can be easily translated to
that for the expected neutrino energy spectrum of the oscillated events.
As can be seen, if the neutrino energy spectrum of the oscillated events could be reconstructed with sufficiently 
good resolution in order to distinguish first and second maximum, useful information to extract the 
CP phase would be available even only with a neutrino run.
%
%
%
%Figure~\ref{fig:spectrum} shows
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{spectrum}
%\caption{$\mu_\mu\to\nu_e$ Oscillation Probability as a Function of Energy/Baseline for various $\delta$}
%\label{fig:spectrum}
%\end{center}
%\end{figure}
If baseline is set to be long, 1) energy of 2nd oscillation maximum gets measurable.
2) statistical significance may get worse, and 3) measurement is affected by large matter effect.
On the other hand, if baseline is set to be short, 1) it is impossible to extract 2nd oscillation maximum information, 2) statistical significance may
get better, and 3) measurement is  less affected by matter effect.
%
% is getting high
%  %
%
%
%Baseline
%\begin{itemize}
%\item Long: 
%      good for 2nd Osc. Max. at Measurable Energy
%      bad Less Statistics
%      sometime good sometime harmfull Large Matter Effect
%\item Short:
%      good for  High Statistics
%      bad  2nd Osc.Max.Too Low Energy to Measure
%5      sometime good sometime harmfull Less Matter Effect
%5\end{itemize}
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%At this stage of our investigations, 
%the emphasis is placed on the measurement of the $\theta_{13}$ and $\delta_{CP}$ parameters,
%possibly following indications for a non-vanishing $\theta_{13}$ in T2K.
%
%Our emphasis is based on the measurement of the $\theta_{13}$ and $\delta_{CP}$ parameters,
%possibly following indications for a non-vanishing $\theta_{13}$ in T2K,
%and relies on the opportunity offered by the LAr TPC to reconstruct the incoming
%neutrino energy with high precision compared to other large detector
%technologies. 
%5
%The most important experimental aspects here are the beam profile (e.g.
%the ability to cover with sufficient statistics the $1^{st}$ maximum
%of the oscillation, the $1^{st}$ minimum, and the $2^{nd}$
%5maximum), the visible energy resolution of the detector, with which
%the neutrino energy can be reconstructed, and the spectrum
%of the misidentified background (e.g. $\pi^0$ spectrum, etc.).
%
%The approach of our paper is different. We consider the physics performance of 
%a single 100~kton next  generation liquid Argon Time Projection Chamber (LAr TPC)
%located  in the region of Okinoshima islands corresponding to a (relatively modest) baseline
%$L\sim 658$~km. A detector in this location will automatically see the J-PARC
%neutrino beam at an off-axis angle of $\sim 0.8^\circ$. As we show below, this configuration
%allows to study both 1st and 2nd oscillation maximum peaks with good
%5statistics. We rely on the realistic opportunity offered by the increase of intensity of the J-PARC MR 
%and on the higher precision of the LAr TPC  than other large detectors to separate
%the two peaks. In addition, the $\pi^0$ background is expected to be highly suppressed
%thanks to the fine granularity of the readout, hence the main irreducible background
%will be the intrinsic $\nu_e$ component of the beam.%
%
%Figure~\ref{Fig:OPloe} shows the oscillation probability as a function 
%of the E(GeV)/ L(km) (neglecting for the moment matter effects). 
%In the plot, the mixing angle $\sin^2 2\theta_{13}$ was assumed to be 0.1.
%If the distance between source and detector is fixed, the curves can be easily translated to
%that for the expected neutrino energy spectrum of the oscillated events.
%As can be seen, if the neutrino energy spectrum of the oscillated events could be reconstructed with sufficiently 
%good resolution in order to distinguish first and second maximum, useful information to extract the 
%CP phase would be available even only with a neutrino run.
%
%We note that the following observables depend on leptonic CP phase:
%\begin{itemize}
%\item position/height of the first oscillation maximum peak;
%\item position/height of the second oscillation maximum peak.
%\end{itemize}
%The position of the first oscillation minimum is unaffected by it
%(in this point all terms of the oscillation probability vanish except the solar term).
%To effectively experimentally study these observables, we point out that:
%\begin{itemize}
%\item the second oscillation maximum peak should end up at
%sufficiently high energy in order to be measurable;
%\item the beam should have a sufficiently wide energy range to
%cover the 1st and 2nd maximum;
%\item the neutrino flux should be maximized in order to increase as much as possible the statistical significance
%of the first and second maxima. 
%\end{itemize}
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%Additional Requirement for Far Detector Optimization
%
%Needless to say, there is important additional requirement 
%\begin{itemize}
%\item Proton Decay Discovery Performance
%\item Realization of the Huge Detector
%\begin{itemize}
%\item Test of the key components
%\item Prove the detector performance experimentally
%\begin{itemize}
%\item if necessary, good prototyping
%   (to be able to predict Huge Detector Performance)
%\item Test with the particles is important
%\end{itemize}
%\end{itemize}
%\end{itemize}
%

To define far detector option,
discovery potential for proton decay and reality to realize huge one 
are also the essential issues to be taken into account.
%KEK has started R$\&$D to realize huge Liquid Argon Time Projection Chamber.
%see Dr. Alberto Marchionni�fs talk in Detector Session
%
%The construction and operation of a 100~kton liquid Argon TPC certainly represents
%a technological challenge at the present state of knowledge of the technique. 
%For it to become a realistic option, we stress the 
%importance and necessity of further R\&D and of dedicated experimental measurement
%campaigns. At this stage, we intend to pursue our investigations on a ton-scale prototype 
%based on the novel double-phase readout imaging method. Options to operate small
%devices in the J-PARC neutrino beam are being assessed in parallel. In addition, 
%we have started to address the possibility of an ``intermediate'' prototype, presumably
%in the range of 1~kton of mass, based on a similar but scaled down design
%of the potential 100~kton detector.




\subsection{Possible scenarios for new generation discovery experiment with J-PARC neutrino beam}

The study of possible new generation discovery experiments with J-PARC neutrino beam was
initiated at the 4th International Workshop on Nuclear and Particle Physics at J-PARC (NP08)~\cite{NP08}.
With the same configuration as T2K (2.5$^\circ$ off-axis angle),
%
%
%
%
%
%The J-PARC neutrino beam line was designed and constructed in order to allow an off-axis angle with respect
%to Super-Kamiokande (SK) between 2.5$^\circ$ and 3$^\circ$. A beam setup yielding an OA2.5$^\circ$ at SK was
%chosen for the T2K experiment. 
%In this configuration, 
the center of the neutrino beam will go through underground beneath SK (295~km baseline), and 
will automatically reach the Okinoshima island region (658~km baseline) with an off-axis angle $0.8^\circ$ (almost on-axis) 
and eventually the sea level east of the Korean shore (1,000~km baseline) with an off-axis angle $\sim 1^\circ$. 
%
%
%Larger off-axis angles are obtained moving inland Korea (either north, south or west).
%Figure~\ref{Fig:BLcand} shows these baseline options using the same
%beam configuration as the T2K experiment. Parameters for different baselines 
%and beam axes are summarized in Figure~\ref{Fig:BLcand} and 
%Table~\ref{Tab:BLcand}. 
%
%Same beam configuration as T2K experiment
%
%NP08 is  The 4th International Workshop on Nuclear and Particle Physics at J-PARC
%http://j-parc.jp/NP08
%(Figure~\ref{fig:scenario})
%%\begin{figure}[htb]
%%\begin{center}
%%\includegraphics[width=9cm,angle=-90]{scenario}
%\caption{Three possible scenarios studied at NP08 workshop}
%\label{fig:scenario}
%\end{center}
%\end{figure}
%
%\subsubsection{Scenario 1: J-PARC to Okinoshima}
%
%Cover 1st  and 2nd Maximum
%Neutrino Run Only  5Years�~1.66MW
%100kt Liq. Ar TPC
%-Good Energy Resolution
%-Good e/�΂Odiscrimination
%Keeping Reasonable Statistics
%658km
%0.8deg. almost On-axis
%NP08, arXiv:0804.2111
%(Fig.~\ref{fig:scenario1})
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{scenario1}
%\caption{Scenario 1: J-PARC to Okinoshima }
%\label{fig:scenario1}
%\end{center}
%\end{figure}
%
%At this stage of investigations, 
%the emphasis is placed on the measurement of the $\theta_{13}$ and $\delta_{CP}$ parameters,
%possibly following indications for a non-vanishing $\theta_{13}$ in T2K.



\subsubsection{Scenario 1: J-PARC to Okinoshima Long Baseline Neutrino Experiment}
The first scenario is ``J-PARC to Okinoshima Long Baseline Neutrino Experiment'' as shown in Fig.~\ref{fig:scenario1}~\cite{okinoshima}.
\begin{figure}[htb]
\begin{center}
\includegraphics[width=9cm,angle=-90]{scenario1}
\caption{Scenario 1: J-PARC to Okinoshima Long Baseline Neutrino Experiment}
\label{fig:scenario1}
\end{center}
\end{figure}
In order to cover a wider energy range,
detector location which is near on-axis is favored.
If one assumes that the second oscillation maximum has to be located at an energy larger than  
about 400~MeV, the baseline should be longer than about 600~km.
In addition, in order to collect enough statistics, baseline should not be too much 
longer than above stated.
Taking into account all of the above mentioned considerations, 
the Okinoshima region (658~km baseline and almost on-axis (0.8$^\circ$ off-axis) configuration) turns out to be ideal.
%we privilege the Okinoshima region:
%placing a detector in an appropriate location on the island~\footnote{\setlength{\baselineskip}{4mm}The exact location of 
%the potential experiment in Okinoshima has not
%yet been investigated, but we note that the island has several hills.} will 
%probe neutrino oscillations at a baseline of $\sim 658$~km away from the source
%at an off-axis angle of $\sim 0.8^\circ$.

%o remain conservative, 
Analysis here based on the assumption using a neutrino run only
during five years to be reasonable time duration for the single experiment ($10^7$~seconds running period/year is assumed), 
under the best J-PARC beam assumption. An anti-neutrino beam
(opposite horn polarity) might be considered in a second stage in order to cross-check
the results obtained with the neutrino run (in particular for mass hierarchy problem).
%The approach of our paper is different. We consider the physics performance of
Detector is assumed to be a 100~kton liquid Argon time projection chamber.
This type of detector is supposed to provide  higher precision than other huge detectors to separate
the two peaks in energy spectrum. In addition, the $\pi^0$ background is expected to be highly suppressed
thanks to the fine granularity of the readout, hence the main irreducible background
will be the intrinsic $\nu_e$ component of the beam.
%Table~\ref{Tab:NuRate} shows that total number of charged current (CC)
%events at Okinoshima for the null oscillation case and the number of CC $\nu_e$ events
%from $\nu_\mu\rightarrow \nu_e$ oscillations for three different mixing angles, and
% in various $\delta_{CP}$ scenarios, normalized to five years neutrino run
%at 1.66~MW and 100~kton fiducial mass.
%
%\begin{table}[htb]
%\begin{center}
%\begin{tabular}{lcccc} 
%\hline \hline 
%\multicolumn{5}{c}{Events for 100~kton at Okinoshima normalized to 5 years at 1.66~MW beam power}\\
%\hline
% & $\nu_{\mu}$ & $\nu_e$ & $\bar{\nu}_{\mu}$ & $\bar{\nu}_e$\\ \hline
%Beam components (null oscillation)  &  82000  & 750 & 1460 & 35 \\
%\hline \hline 
%\multicolumn{5}{c}{$\nu_\mu\rightarrow \nu_e$ oscillations }\\
%  $\delta_{CP}=$& $0^{\circ}$ & 90$^{\circ}$ & 180$^{\circ}$ & 270$^{\circ}$\\ \hline
%  $\sin^2 2\theta_{13}$ = 0.1 & 2867 & 2062 & 2659 & 3464  \\
%  $\sin^2 2\theta_{13}$ = 0.05 & 1489 & 1119 & 1342 & 1908  \\
%  $\sin^2 2\theta_{13}$ = 0.03 & 942 & 506 & 829 & 1266  \\
%\hline
%\end{tabular}
%\caption{\setlength{\baselineskip}{4mm}
%Number of CC events at Okinoshima: beam components for null oscillation,
%and oscillated events in various $\delta_{CP}$ scenarios
%(normalized to five years neutrino run)
%}
%\label{Tab:NuRate}
%\end{center}
%\end{table}
%
%The number of expected events is already a good indicator of the signal, but for this
%analysis we use binned likelihood fitting for the energy spectrum, 
%therefore all information including total number of events is 
%taken into account, as described in the next section.
%
%
%
The right hand side plot in Figure~\ref{fig:scenario1} shows the energy spectra of electron neutrino 
at the cases 
of $\delta$ equal 0$^{\circ}$, 90$^{\circ}$, 180$^{\circ}$, 
270$^{\circ}$, respectively. Shaded region is common for all 
plots and it shows the background from beam $\nu_e$.
Here perfect resolution is assumed.
%
%
% for reference to later cases.
%
%\begin{figure}[htb]
%
%\begin{minipage}[b]{0.5\linewidth}
%
%\centering
%\includegraphics[angle=0, width=9.0cm]{wbkg.eps}
%\caption{\setlength{\baselineskip}{4mm}
%Energy spectra at $\sin^2 2\theta_{13}$=0.03 case, but 
% $\delta_{CP}$ = 0$^{\circ}$ (top-left), 90$^{\circ}$ (right-top),
%180$^{\circ}$ (left-bottom), 270$^{\circ}$ (right-bottom) cases. 
%}
%\label{Fig:ES0mev}
%
%\end{minipage}
%\hspace{0.5cm}
%\begin{minipage}[b]{0.5\linewidth}
%
%\centering
%\includegraphics[angle=0, width=9.0cm]{sens_wbkg.eps}
%\caption{\setlength{\baselineskip}{4mm}
% Allowed regions in the perfect resolution case.
% Twelve allowed regions are overlaid for twelve true values,
% $\sin^2 2\theta_{13}$=0.1, 0.05, 0.02, and $\delta_{CP}$=0$^{\circ}$,
% 90$^{\circ}$, 180$^{\circ}$, 270$^{\circ}$, respectively.
%}
%\label{Fig:Allowed_0mev}
%
%
%\end{minipage}
%
%\end{figure}
%
%
%Assuming all others were measured very precisely, 
%there are only two free parameters $\sin^2 2\theta_{13}$ and $\delta_{CP}$
%to be fitted using the energy spectra.
%As shown in Figure~\ref{Fig:OPloe}, 
As shown, the value of $\delta$ varies the energy 
spectrum, especially the first and the second oscillation peaks (heights
and positions), therefore comparison of the peaks
determine the value $\delta$, while the value of $\sin^2 2\theta_{13}$ changes 
number of events predominantly.
%
%To fit the free parameters, a binned likelihood method is used.  
%The Poisson bin-by-bin probability of the observed data from the expected events 
%(for an assumed pair of values ($\sin^2 2\theta_{13}$, $\delta_{CP}$))
% is calculated. The fit procedure is  validated by testing the result
% on a pseudo-experiment. Figure~\ref{Fig:aPE} shows one typical pseudo-experiment for the perfect
%resolution case (with $\delta_{CP}$ equals to 0, and $\sin^2 2\theta_{13}$
%equals to 0.1). Best fit gives reasonable result.
%%
%\begin{figure}[htbp]
%\begin{center}
%\includegraphics[angle=0, width=8.0cm]{one_pe.eps}
%\caption{\setlength{\baselineskip}{4mm}
% Typical one pseudo-experiment to show the validity of the fitting.
% Histogram shows the best-fit (best oscillation shape + background), and
% the crosses show the pseudo-data. 
%}
%\label{Fig:aPE}
%\end{center}
%\end{figure}
%
%At this stage, we only take statistical uncertainty into account for the fitting, thus
%other systematic uncertainties like far/near ratio, beam $\nu_{e}$ shape,
%energy scale, and so forth are not considered.
%Also, oscillated signal and beam $\nu_{e}$ are only accounted 
%in the fit, i.e. other background 
%like neutral current $\pi^{0}$ or beam $\bar\nu_{e}$ contamination
%is assumed to be negligible compared to beam $\nu_{e}$ contamination.
%5
%At this stage, we only take statistical uncertainty into account for the fitting, thus
%other systematic uncertainties like far/near ratio, beam $\nu_{e}$ shape,
%energy scale, and so forth are not considered.
%Also, oscillated signal and beam $\nu_{e}$ are only accounted 
%in the fit, i.e. other background 
%like neutral current $\pi^{0}$ or beam $\bar\nu_{e}$ contamination
%is assumed to be negligible compared to beam $\nu_{e}$ contamination.
%
%
%\subsection{Perfect resolution case}
%\indent
Allowed regions in the perfect resolution case are shown in left hand side of 
Figure~\ref{fig:scenario1}. Twelve allowed regions are overlaid for twelve true values,
$\sin^2 2\theta_{13}$=0.1, 0.05, 0.02, and $\delta$=0$^{\circ}$,
 90$^{\circ}$, 180$^{\circ}$, 270$^{\circ}$, respectively.
The $\delta$ sensitivity is 20$\sim$30$^\circ$ depending 
on the true $\delta$ value. 

%a) a 100kt liquid argon detector  in Okinoshima, a small island 658 km away from the neutrino source. The beam would be slightly off-axis. Both the first and %second oscillation maxima would be studied in the same detector.   

\subsubsection{Scenario 2: J-PARC to Kamioka Long Baseline Neutrino Experiment}
Second scenario is ``J-PARC to Kamioka Long Baseline Neutrino Experiment'' as shown in Fig.~\ref{fig:scenario2}~\cite{NP08}.
\begin{figure}[htb]
\begin{center}
\includegraphics[width=9cm,angle=-90]{scenario2}
\caption{Scenario 2: J-PARC to Kamioka Long Baseline Neutrino Experiment}
\label{fig:scenario2}
\end{center}
\end{figure}
The concept is same as T2K except for huge detector size whose fiducial volume is assumed to be 570~kt.
%
%The neutrino flux at the first oscillation maximum is 
%not much cancellation is expected for nu and anti nu run
The baseline of 295~km and off-axis angle of  2.5$^\circ$ are optimum for the experimental sensitivity with a water cherenkov detector
as they are  for T2K.
%
%1) in order to maximize sensitivity, narrow band neutrino beam whose intensity maximum set to be first oscillation maximum.
%1) to maximize neutrino flux at the energy of the first oscillation maximum, 
%2) to avoid severe $\pi^0$ background originated from high energy neutrino interaction, and 
%3) to tune neutrino energy range to be optimum for water cherenkov detector (GeV energy region, low multiplicity and quasi elastic interaction dominant.).
With this configuration, on the other hand, it is only possible to cover 1st oscillation maximum.
In order to investigate difference between neutrino and anti-neutrino behavior with sufficient statistics,
2.2~years ($10^7$~seconds running period/year is assumed) neutrino run and 7.8~years anti-neutrino run is required.
Since the cancellation of systematic uncertainty between neutrino run and anti-neutrino run is not much expected,
the way to deal with delicate systematic uncertainty is a important issue to be seriously considered.

\subsubsection{Scenario3: J-PARC to Kamioka and Korea Long Baseline Neutrino Experiment}
Third scenario is ``J-PARC to Kamioka and Korea Long Baseline Neutrino Experiment'' as shown in Fig.~\ref{fig:scenario3}~\cite{NP08}.
\begin{figure}[htb]
\begin{center}
\includegraphics[width=9cm,angle=-90]{scenario3}
\caption{Scenario 3: J-PARC to Kamioka and Korea Long Baseline Neutrino Experiment}
\label{fig:scenario3}
\end{center}
\end{figure}
This plan is partially same as scenario 2.
In order to obtain 1st and 2nd oscillation maxima information, in addition to neutrino and anti-neutrino difference,
two 270~kt water cherenkov detectors, one at Kamioka (295~km baseline) and the other in Korea (1,000~km baseline) are utilized.
It would allow to study E/L regions corresponding to the 1st oscillation maximum at Kamioka and 2nd oscillation maximum at Korea,
at the suitable energy regime for the measurement with a water cherenkov detector.
It requires five years each for neutrino and anti-neutrino run.

Comparison of each scenario is shown in Table~\ref{tab:scenario}. 
Study is continuing to seek for optimum choice to maximize potential of the research.
%
%\section{Comparison of Each Scenario}
%
\begin{table}[htb]
\begin{center}
\caption{Comparison of possible scenarios for new generation discovery experiment with J-PARC neutrino beam}
\label{tab:scenario}
\begin{tabular}{lccc}
\hline\hline
\textbf{}             & \textbf{Scenario 1} & \textbf{Scenario 2} & \textbf{Scenario 3} \\
\textbf{}             & \textbf{Okinoshima} & \textbf{Kamioka} & \textbf{Kamioka and Korea} \\
\hline
 \textbf{Baseline} (km)  & 658 & 295 & 295 and 1000  \\
 \textbf{Off-Axis Angle} ($^\circ$)  & 0.8(almost on-axis) & 2.5 & 2.5 and 1 \\
 \textbf{Method}   & $\nu_e$ Spectrum Shape & Ratio between $\nu_e$ and $\bar{\nu}_e$ &  Ratio between 1st and 2nd Max.   \\
    &  &  &  Ratio between $\nu_e$ and $\bar{\nu}_e$  \\
 \textbf{Beam}   & 5 years $\nu_\mu$ & 2.2 years $\nu_\mu$  &  5 years $\nu_\mu$ \\
    & then Decide Next &  and 7.8 years $\bar{\nu}_\mu$ &  and 5 years $\bar{\nu}_\mu$ \\
 \textbf{Detector Technology}   & Liq. Ar TPC & Water Cherenkov & Water Cherenkov \\
 \textbf{Detector Mass} (kt)   & 100 & 2$\times$270 & 270+270 \\ 
\hline\hline
%\multicolumn{3}{l}{$^{a}$ \footnotesize Notes in tables appear as
%                      this one here.}
\end{tabular}
\end{center}
\end{table}
%
%Study is continuing to seek for optimum choice.
%

\section{Accelerator based neutrino project in Japan}

Table~\ref{tab:project} summarizes accelerator based neutrino project in Japan.
When K2K and T2K projects started, the existence of high performance far main detector, SK, 
made it possible to concentrate on neutrino beam source related preparation.
As for the 3rd generation experiment, the existence of J-PARC neutrino beam make it possible to concentrate on 
far detector issues after T2K starts up.
%
%highly relayin on the exisntence of high quality main far detector SK.
%We are able to concentratte on Far Detector issue toward the 3rd generation experiment after T2K startup.
% is possible to concentrate%
%
%When K2K project started, since high intensity ptoton synchrotron KEK PS and far main detector SK
%already exist. so we can concentrate on beam line construction
%We are able to concentratte on Far Detector issue toward the 3rd generation experiment after T2K startup.
\begin{table}[htb]
\begin{center}

\caption{Accelerator based neutrino project in Japan}
\label{tab:project}
\begin{tabular}{llll}
\hline\hline
\textbf{}             & K2K & \ T2K & \textbf{3rd Generation Experiment} \\
%\textbf{}             & \textbf{} & \textbf{} & \textbf{(KEK Roadmap)} \\
\hline
 \textbf{High Power}   & KEK PS & J-PARC MR & \textbf{J-PARC MR}  \\
 \textbf{Proton}   & 12GeV 0.005MW & 30GeV 0.75MW & \textbf{30GeV 1.66MW}  \\
 \textbf{Synchrotron}   & Existing & Brand New & \textbf{Technically Feasible Upgrade}  \\
\   &  &  &   \\
\textbf{Neutrino Beamline}   & K2K & J-PARC & \textbf{J-PARC}  \\
\textbf{}   & Neutrino Beamline & Neutrino Beamline & \textbf{Neutrino Beamline}  \\
\textbf{}   & Brand New & Brand New & \textbf{Existing}  \\
\   &  &  &   \\
\textbf{Far Detector}   & Super Kamiokande & Super Kamiokand & \textbf{Brand New}  \\
\textbf{}   & Existing at  & Existing at  & \textbf{- Detector Technology ?}  \\
\textbf{}   & KAMIOKA  & KAMIOKA  & \textbf{- Place (Angle and Baseline) ?}  \\
%\textbf{}   &   &  & \textbf{(\it Anglea and Baseline)}  \\
\   &  &  &   \\
\textbf{1st Priority Physics Case}   & Neutrino Oscillation  & Neutrino Oscillation & \textbf{Lepton Sector CP Violation}  \\
\textbf{}   & $\nu_\mu$ Disappearance  & $\nu_\mu \to \nu_e$ & \textbf{Proton Decay}  \\

\hline\hline
%\multicolumn{3}{l}{$^{a}$ \footnotesize Notes in tables appear as
%                      this one here.}
\end{tabular}
\end{center}
\end{table}

To complete present project T2K successfully and realize new generation discovery experiment,
following issues are important.
%\section{What we think important for Accelerator Based Neutrino Project in Japan}
\begin{itemize}
\item Deliver high quality experimental output from T2K as soon as possible. 
\item Realize quick improvement of accelerator power toward MW-class power frontier machine.
\item Validate beam line components tolerance (especially pion production target related issues) toward MW proton beam. 
\item  Conduct intensive R$\&$D on realization of huge liquid Argon time projection chamber and water cherenkov detector. 
\end{itemize}
Healthy scientific competition and cooperation in the world is key to promote high energy physics.
It is welcomed to cooperate in any aspects.
%
% 
%between Asia, EU and USA (Fig.~\ref{fig:comp}).

In Japan we will proceed as following.
%\section{Summary: Accelerator Based Neutrino Project in Japan}
\begin{itemize}
\item Short term
\begin{itemize}
\item Beam commissioning of J-PARC MR has started May-2008.
\item Commissioning of J-PARC neutrino beam facility has started in April-2009.
\item T2K is aiming for the first results in 2010 with 100~kw~$\times$~10$^7$~seconds integrated proton power 
on target to unveil below CHOOZ experimental limit with $\nu_e$ appearance. 
\end{itemize}
\item Middle term
\begin{itemize}
\item T2K data with 1-2~MW~$\times$~10$^7$~seconds integrated proton power on target will provide critical information on
 $\theta_{13}$, which guides the future direction of the neutrino physics. (In any case, complete T2K proposal 
of 3.75~MW~$\times$~10$^7$~seconds.)
\item Achieve MR power improvement scenario toward MW-class power frontier machine (KEK Roadmap).
\item  Submit proposal "J-PARC to Somewhere Long Baseline Neutrino Experiment and 
Nucleon Decay Experiment with Huge Detector" and construct huge detector. 
\end{itemize}
\item Long term
\begin{itemize}
\item Discover CP violation in lepton sector and  proton decay, and solve ``Quest for the Origin of Matter Dominated Universe"
\end{itemize}
\end{itemize}
%
%\section{What we think important for Accelerator Based Neutrino Project in Japan}
%\begin{itemize}
%\item Deliver high quality experimental output from T2K as soon as possible 
%\item Quick improvement of accelerator power toward MW-class power frontier machine
%\item Validate beam line components tolerance (especially pion production target related issues) toward MW proton beam 
%\item  R$\&$D on realization of Huge Detector
%\begin{itemize}
%\item Liq. Ar TPC     
%\item Water Cherenkov Detector
%\end{itemize}
%\end{itemize}
%
%e welcome cooperation in any aspects
%
%We hope Healthy Scientific Competition and Cooperation between Asia, EU and USA.(Fig.~\ref{fig:comp})
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=9cm,angle=-90]{comp}
%\caption{Healthy scientific competicion and cooperation between Asia, EU and USA}
%\label{fig:comp}
%\end{center}
%\end{figure}
%
%
%\section{What we think important for Accelerator Based Neutrino Project in Japan}
%
%A section title is styled as above, and first paragraphs after
%headings are not indented. References appear in numerical
%order~\cite{Raby1966,Dupont1961}. An itemized list looks like the following:
%\begin{itemize}
%\item the first item,
%\item the second item.
%\end{itemize}
%
%You can also have an enumerated list:
%
%\begin{enumerate}
%\item the first item,
%\item the second item.
%\end{enumerate}
%
%\subsection{Subsection heading}
%
%As you see, the first paragraph is not indented. References when part
%      of the text use the term `Ref.', for example, see
%      Ref.~\cite{Raby1966} and
%      Refs.~\cite{Appleman1959,vanBerg1965,Bryant1985,Allen1977}.
%
%Subsequent paragraphs are indented. See Table~\ref{tab:LET} for an
%example of how to display a table.
%
%\begin{table}[htb]
%\begin{center}
%\caption{A simple table}
%\label{tab:LET}
%\begin{tabular}{p{6cm}cc}
%\hline\hline
%\textbf{Heading}             & \textbf{Result 1}
%                                                & \textbf{Result 2}\\
%\hline
%200 kVp X-rays total$^{a}$   & 3.25             & 1.79 \\
%200 kVp X-rays (primary)     & 2.60             & 1.48 \\
%\hline\hline
%\multicolumn{3}{l}{$^{a}$ \footnotesize Notes in tables appear as
%                      this one here.}
%\end{tabular}
%\end{center}
%\end{table}
%
%\subsubsection{Subsubsection title}
%\label{sec:sss}
%
%Equation~(\ref{eq:a1}) is presented correctly:
%\begin{equation}
%n^k(h)= k h \frac{k}{32}~. \label{eq:a1}  
%\end{equation}
%
%This is how all equations should be formatted,
%including~Eqs.~(2)--(10), 
%%% With LaTeX use: Eqs,~(\ref{eq:a2})--(\ref{eq:a10}) syntax.
%which are not shown\footnote{Footnotes are
%to be used only when absolutely necessary.}.
%
%\subsubsubsection{Subsubsubsection title}
%
%Figure~\ref{tab:LET} is an example of how to display figures. Please
%refer to figures as Figs.~2--4, etc.
%% With LaTeX use : Figs.~\ref{fig:a1}--\ref{fig:a4} syntax.
%Section~\ref{sec:sss} is a cross-reference to a section. 
%See the document describing the CERN reports~\cite{cernrep} for more
%details on how to present figures, tables, equations, and much more
%with \LaTeX. 
%
%\begin{figure}[htb]
%\begin{center}
%\includegraphics[width=6cm]{pictexa}
%\caption{Diagram of a straight line}
%\label{fig:line}
%\end{center}
%\end{figure}
%
%Examples of references and a bibliography follow the acknowledgements.
%
%\section*{Acknowledgements}
%
%I wish to thank A.N. Colleague for enlightening comments on
%the present topic.
%
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\end{thebibliography}








%\section*{Bibliography}
%
%
%I.C. Percival and D. Richards, \emph{Introduction to Dynamics}
%(Cambridge University Press, Cambridge, 1982).
%
%\appendix
%\section{Title of appendix}
%\label{sec:app}
%
%\subsection{Subsection title in appendix}
%
%Inside an appendix the same level of headings (section, subsection,
%etc.) as in the main text applies. Only the first number is replaced
%by an uppercase letter.
%
%\subsubsection{Subsubsection title in appendix}%
%
%Inside a subsubsection inside an appendix.
%
%\subsubsubsection{Subsubsubsection title in appendix}
%
\end{document}

