1 | \section{Schedule} |
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2 | |
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3 | The following table presents an optimal schedule for the |
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4 | European project taking into account the key date of the completion |
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5 | of the new tunnel excavation around 2010. Soon after, CERN will have to decide |
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6 | its post-LHC strategy, while nuclear physicists will hopefully choose CERN as |
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7 | the host laboratory for the EURISOL project. |
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8 | We would also like to stress that |
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9 | the schedule of the neutrino beams from CERN is not constraining the |
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10 | start of the other non accelerator items of research. |
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11 | \begin{figure}[htb] |
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12 | \vspace{4cm} |
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13 | \epsfig{figure=./figures/sch_new.eps,width=\textwidth,angle=0} |
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14 | %\epsfig{figure=./figures/sch.eps,width=0.6\textwidth,angle=-90} |
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15 | \end{figure} |
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16 | |
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17 | \newpage |
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18 | \section{Conclusions} |
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19 | In conclusion a megaton scale |
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20 | Water \v{C}erenkov detector at the Frejus site will address a series of |
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21 | fundamental issues : |
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22 | \begin{itemize} |
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23 | \item explore the nucleon decay with a sensitivity an order of magnitude |
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24 | better than current limits on different channels |
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25 | \item in the case of a galactic or near galactic supernova explosion, |
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26 | track the explosion in unprecedented detail providing at the same time |
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27 | information on the third oscillation angle beyond what is currently |
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28 | achievable in terrestrial experiments |
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29 | \item provide a trigger for supernova explosions |
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30 | for other astroparticle detectors for supernova exploding in a range of up to |
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31 | 3 Mpc, knowing that 1 supernova explosion per year is expected |
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32 | within a distance of |
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33 | 10 Mpc |
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34 | \item provide a 4 sigma detection of diffuse supernova |
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35 | neutrinos after 2-3 years of operation |
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36 | \item in association with a superbeam and betabeam from CERN |
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37 | obtain a sensitivity to the third oscillation angle down to |
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38 | $\sin^2(2\theta_{13}) \sim 10^{-4}$ and detect maximal CP violation at 3 sigmas |
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39 | for $\sin^2(2\theta_{13})$ larger than $3\cdot 10^{-4}$ |
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40 | \end{itemize} |
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41 | A series of other physics topics, not mentioned here, will also be adressed\,: |
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42 | for instance neutrino physics, as well as |
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43 | interdisciplinary topics in rock mechanics, geobiology, geochemistry, |
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44 | geohydrology, geomechanics and geophysics that could benefit |
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45 | from a large scale underground excavation. |
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46 | |
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47 | We believe that our project compares favorably with other similar |
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48 | projects around the world, and should be seriously considered as a |
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49 | very attractive major European project after the LHC. The proposed |
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50 | strategy is thus the following: a megaton-scale detector could be |
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51 | installed at Fr{\'e}jus and start physics in 2018. It would start |
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52 | proton decay and supernova searches, which would last several |
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53 | decades. As soon as the neutrino beam from SPL is available, |
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54 | neutrino oscillation studies can start, and the advent of a beta beam |
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55 | would increase significantly the performances of the detector. |
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56 | |
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57 | The signatories are eager to see the MEMPHYS project |
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58 | come to life. They are aware that the actual location of a megaton detector |
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59 | will depend on many issues, in particular the share of future big equipments |
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60 | (such as linear colliders) worldwide. They are prepared to do the proposed |
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61 | physics in any country, and have already set up collaborations with their |
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62 | japanese and american colleagues. An inter-regional yearly (US-Europe-Japan) |
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63 | workshop series NNN-XX (Next generation of Nucleon decay and Neutrino Physics |
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64 | detectors) organizes and structures this convergence of interests. |
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65 | The authors of this document hope however that Europe will not |
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66 | miss a unique opportunity to keep a leading role in the underground physics, |
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67 | complementary to the Gran Sasso. |
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68 | |
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69 | Furthermore, it is obvious that the current proposal is complementary |
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70 | to other proposals for large undergrounds detectors using |
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71 | liquid scintillator (LENA) or liquid argon technologies (GLACIER) |
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72 | in order to pursue the same physics goals. |
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73 | The advantage of the water \v{C}erenkov technique lies on the possibility |
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74 | to instrument very large masses, while liquid argon detectors |
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75 | can have an excellent resolution and liquid scintillators |
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76 | very low detection thresholds for neutrino physics. |
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77 | On the technology side the water \v{C}erenkov seems a straightforward |
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78 | extension of the existing techniques while for instance the liquid argon |
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79 | option presents daring technological challenges. The realisation of the |
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80 | complementarities in physics potential and the common R\&D issues |
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81 | (large underground caverns and containers: excavation issues and safety, |
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82 | large area low cost photodetection and electronics, |
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83 | purification and background issues, interdisciplinary issues, etc.) |
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84 | prompted the proponents of the above solutions to start federating |
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85 | their efforts in order to exploit the possible synergies in view of |
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86 | common future proposals to the European Union ~\cite{Laguna} |
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87 | and elsewhere. |
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88 | |
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89 | |
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90 | |
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91 | \section {Acknowledgements} |
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92 | |
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93 | The authors would like to thank the engineers of the IN2P3-CNRS laboratories, |
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94 | especially Ch. de La Taille (LAL) and J. Pouthas (IPNO), |
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95 | for their decisive contributions. |
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96 | |
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97 | |
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