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J. Bouchez CEA/DAPNIA

J. Bouchez CEA/DAPNIA. CHIPP Neuch â tel June 21, 2004. A NEW UNDERGROUND LABORATORY AT FREJUS Motivations and prospects. NEMO 3. PRESENT EXPERIMENTS. EDELWEISS II Set up. Paraffin. Ge. Lead. He. How to overcome superbeam limitations ?. Main problem :

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J. Bouchez CEA/DAPNIA

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  1. J. Bouchez CEA/DAPNIA CHIPP Neuchâtel June 21, 2004 A NEW UNDERGROUND LABORATORY AT FREJUSMotivations and prospects

  2. NEMO 3 PRESENT EXPERIMENTS EDELWEISS II Set up Paraffin Ge Lead He

  3. How to overcome superbeam limitations ? Main problem : SPL protons produce less negative pions, so less antineutrinos antineutrino cross-section ~ 5 times smaller than neutrinos So 10 SPL years have to be shared as ~ 2 neutrino + 8 antineutrino years The solution : Produce a n e beam to study n e  nm oscillation and run it SIMULTANEOUSLY with n m beam from SPL Compare n m  ne and ne  n m(T asymetry, equivalent to CP asymetry) THIS WAS THE INITIAL MOTIVATION FOR A BETA BEAM

  4. BETA BEAMS • Concept proposed by Piero Zucchelli • Produce radioactive ions (ISOL technique) • Accelerate them in the CERN accelerator complex up to G of order 100 • Store ions in a storage ring with long straight sections aimed at a far detector • Advantages • strongly focussed neutrino beam due to small Q value of beta decays • (quality factor G/Q) • very pure flavour composition ( n m contamination ~ 10 -4 ) • perfectly known energy spectrum • Baseline scenario studied at CERN (Mats Lindroos and collaborators) • Possible synergy between beta beams and EURISOL (Moriond workshop) • Updated study of expected performances (Mauro Mezzetto)

  5. Intensities (original design) Only b-decay losses accounted for, add efficiency losses (50%)

  6. baseline scenario updated for new conditions: • simultaneous running of He6 and Ne18 • new values of gamma factors • 3 Eurisol targets for Ne18 antineutrino flux from He6 ( γ=60) 1.15 1011/second neutrino flux from Ne18 ( γ=100) 0.18 1011/second

  7. How to improve the fluxes ? R&D on ISOL targets Increase ion collection time (factor 1.5 to 2) Flat bottom in the SPS (factor 1.5) Faster PS (factor 2 or more due to less transmission losses) Improvement factors of 5 or more seem realistic For the sensitivity studies, improvement factors of 2.8 for He6 and6.3 for Ne18 have been chosen. These numbers will be refined (among others) in the new version of the baseline scenario within 1 year antineutrino flux from He6 ( γ=60) 2.9 1011/second neutrino flux from Ne18 ( γ=100) 1.1 1011/second

  8. Performances of super + beta beams • Working hypotheses (Mauro Mezzetto): • Announced intensities for ne and anti ne (with 3 ISOL targets for Neon) • UNO-like detector installed at a new Frejus underground laboratory • 10 years running of both SPL and beta beam: • - 2 years of nm • - 8 years of anti nm • - 10 years of ne • - 10 years of anti ne • Since 18 Ne and 6 He ions do not have the same rigidity, the anti ne • energy will be 1.67 times the ne energy • THIS NEEDS TUNING TO FIND THE BEST COMPROMISE

  9. Lorentz boost optimization : Preferred values between g = 55 and 75

  10. Rates for 4400 kT.years • cc evts (no osc, nocuts) 19710 144784 36698 23320 • oscillated at Chooz limit 612 5130 1279 774 • total oscillated (δ=900, =30) 44 529 93 82 • δ term -9 57 -20 12 • beam background 0 0 140 101 • detector background 1 397 37 50 beta beam superbeam He6 Ne18νμ anti ν γ=60 γ=100 2 y 8 y

  11. 13 sensitivity (δ=0) after 5 years (Minos 2 years) 90%CL

  12.  13and d measurements using superbeam and betabeam SPL: 2 years in nm + 8 years in anti nm BETABEAM: 10 years of 6He AND18Ne (Mauro Mezzetto)

  13. 90%CL sensitivity after 5 years (Superbeams νμ only)

  14. 99%CL sensitivity to maximal CP violation after 10 years (SPL-SB 2 years + 8 years)

  15. 3 σ discovery potential after 10 years

  16. Conclusions • Frejus (or TGV) tunnels offer an excellent quality underground site for megaton physics • It is a the right distance from CERN to receive neutrino super and/or betabeams • The Cerenkov technique is adequate given the low energy of the beams • It offers the best sensitivity on 13and δcompared to similar projects (HyperK, BNL/FNAL) • France (IN2P3/CEA) and Italy (INFN) have agreed to join efforts for the promotion of this project • There is a successful coordination between nuclear physicists pushing EURISOL and neutrino physicists (common TDS) • The first experiment able to detect CP violation could be installed in Europe before 2020, and it would also address the fundamental question of proton stability with some chance of discovery.

  17. Short term: • present the project to the SPSC at Villars • prestudy results for the cavity • write a white paper • continue simulations and optimizations

  18. THE END (but to be continued) My warmest thanks to the all the people who have worked hard on this project Special thanks to Mats Lindroos Mauro Mezzetto

  19. USERS Frejus Gran Sasso High Gamma Astro-Physics Nuclear Physics (g, intensity and duty factor) OTHER LABS TRIUMF FFAG Tracking Collimators US study Neutrino Factory DS Conceptual Design # with price ### M€ Design Study EURISOL Beta-beam Coordination Beta-beam parameter group Above 100 MeV/u Targets 60 GHz ECR Low energy beta-beam And many more…

  20. scenario 1 (refurbished SPS) He6 350 Ne18 580 scenario 2 (LHC) 1500 2500

  21. scenario 1

  22. scenario 2 400 kt detector at 730 km (off peak)

  23. :to be studied : • Is it possible to reach equilibrium at higher gamma ? • Need sizeable increase in accelerating power • Size of the decay ring • cost Which schedule? • scenario 1: 2 year stop of SPS, after several years of LHC • scenario 2: After LHC programm I consider this project as a potential 2nd generation beta-beam, not a competitor to the standard beta-beam

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