[387] | 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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