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Elena WILDNER CERN f or the ESSnuSB Collaboration

ESS nuSB Project for Leptonic CP Violation Discovery based on the European Spallation Source Linac. Elena WILDNER CERN f or the ESSnuSB Collaboration. The European Spallation Source (ESS). ESS is a neutron spallation source that will be built by a collaboration of 17 European countries.

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Elena WILDNER CERN f or the ESSnuSB Collaboration

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  1. ESSnuSBProject for Leptonic CP Violation Discovery based on the European Spallation Source Linac Elena WILDNER CERN for the ESSnuSB Collaboration E. Wildner, CERN

  2. The European Spallation Source (ESS) • ESS is a neutron spallation source that will be built by a collaboration of 17 European countries. • ESS is located in southern Sweden (Lund) ESS Technical Design Report, April 23, 2013, ESS-doc-274 http://europeanspallationsource.se/documentation/tdr.pdf E. Wildner, CERN

  3. ESS as proton driver for spallation E. Wildner, CERN

  4. European Spallation Source The ESS has broken ground last week http://europeanspallationsource.se/ess-gets-green-light Contributions by Member Country E. Wildner, CERN

  5. ESS 5MW proton linac • The ESS will be a copious source of spallation neutrons • 5 MW average beam power • 125 MW peak power • 14 Hz repetition rate (2.86 ms pulse duration, 1015 protons) • 2.0 GeV protons (up to 3.5 GeV with linac upgrades) • >2.7x1023p.o.t/year Linac ready by 2023 (full power and energy) ESS Technical Design Report, April 23, 2013 ESS-doc-274 http://europeanspallationsource.se/documentation/tdr.pdf E. Wildner, CERN

  6. ESSnuSB on ESS site Preliminary ! Civil engineering to be taken into account for accumulator! > 2 GeV 2 GeV • p • H- • Neutron • spallation • target ~1 BEuros for the neutrino facility including detector E. Wildner, CERN

  7. ESS H- acceleration for neutrinos ? H- ? • The ESS linac for neutron spallation: proton acceleration 14 Hz • Duty factor low (4%); some additional capacity is available • Repetition rate can be increased to 70 Hz to permit 4 extra acceleration cycles 2.86 / 4 ms long (= 5 MW) • Charge in the accumulator (1.1 1015)/4 p, 2 GeV • >2.7x1023p.o.t/year for neutrinos • ESS would accelerate in total 10 MW! E. Wildner, CERN

  8. ESS Accumulator for neutrino production • Constraints on present neutrino target focusing system: short pulses • Solution: reduce beam pulse length: • Shorten the linac pulse by accumulating the linac beam • Accumulator constraints • Reasonably-sized accumulator ring circumference and apertures • Multiturn injection of high intensity linac beam: we need H- • High intensities in the ring may cause collective effects and beam loss E. Wildner, CERN

  9. Linac Pulsing 70 Hz, baseline Neutrino (H- -pulse) Neutron (proton pulse) 71.4 ms, 14 Hz 35.7 ms 28 Hz Insert one H- pulse 28 Hz 2.86 ms 71.4 ms, 14 Hz Mitigation of charges in accumulator, 70 Hz, implies some overhead (cavity filling) 70 Hz 14.28 ms 2.86 ms 0.7 ms Nufact14, Glasgow, E. Wildner

  10. ESSnuSB on ESS site τH1.5 μs > 2 GeV 2 GeV τ0= 100 μs • p • H- • Neutron • spallation • target Target Station 25 m below ground level Decay tunnel under the linac! URGENT STUDY of ground water! Bending Radius: 133 m for 3 GeV (70 m for 2 GeV) E. Wildner, CERN

  11. The Linac has to be upgradedModulators and infrastructure (C. Martins) To be prepared for at an early stage E. Wildner, CERN

  12. Previous Expertise E. Wildner, CERN

  13. The MEMPHYS WC Detector(MEgaton Mass PHYSics) • Proton decay • Astroparticles • Understand the gravitational collapsing: galactic SN ν • Supernovae "relics" • Solar Neutrinos • Neutrino Oscillations (Super Beam, Beta Beam) • Atmospheric Neutrinos • 500 ktfiducial volume (~20xSuperK) • Readout: ~240k 8” PMTs • 30% optical coverage (arXiv: hep-ex/0607026) E. Wildner, CERN

  14. Possible locations for far detector ESS Kongsberg Løkken CERN E. Wildner, CERN

  15. Neutrino Oscillations with "large" θ13 2nd oscillation maximum P(νμ→νe) 1st oscillation maximum θ13=8.8º ("large" θ13) dCP=-90 dCP=0 dCP=+90 θ13=1º ("small" θ13) L/E L/E solar atmospheric for "large" θ13 1st oscillation maximum is dominated by atmospheric term, for small θ13 1st oscillation maximum is better atmospheric solar L/E L/E CP interference CP interference (arXiv:1110.4583) θ13=1º θ13=8.8º • 1st oscillation max.: A=0.3sinδCP • 2nd oscillation max.: A=0.75sinδCP more sensitivity at 2ndoscillation max. (see arXiv:1310.5992 and arXiv:0710.0554) E. Wildner, CERN

  16. ESS neutrino energy distribution at 100 km from the target and per year E. Wildner, CERN

  17. Neutrino spectra E. Fernandez below ντ production 540 km (2 GeV) neutrinos anti-neutrinos δCP=0 2 years 8 years E. Wildner, CERN

  18. δCP accuracy performance(USA snowmass process, P. Coloma) • for systematic errors see: • Phys. Rev. D 87 (2013) 3, 033004 [arXiv:1209.5973 [hep-ph]] • arXiv:1310.4340 [hep-ex] Neutrino "snowmass" group conclusions "default" column E. Wildner, CERN

  19. Results including nuSTORM Systematics are basicallythe same as before. nuSTORM plots assume that cross sections are determined at the 1% level of precision, removing the constraint between the cross sections for different flavors, they are all allowed to vary independently in the fit. LBNF (40 kton detector, 1.2MW beam power) Pilar Coloma et al. E. Wildner, CERN

  20. 2nd Oscillation max. coverage 2nd oscillation max. well covered by the ESS neutrino spectrum 1st oscillation max. E. Fernandez E. Wildner, CERN

  21. Which baseline? E. Fernandez CPV MH Garpenberg Zinkgruvan • Zinkgruvan is better for 2 GeV 360 km • Garpenberg is better for > 2.5 GeV 540 km • systematic errors: 5%/10% (signal/backg.) • Zinkgruvan is better • atmospheric neutrinos are needed (at least at low energy) E. Wildner, CERN

  22. Systematic errors Phys. Rev. D 87 (2013) 3, 033004 [arXiv:1209.5973 [hep-ph]] E. Wildner, CERN

  23. Systematic errors and exposure for ESSnuSB systematic errors see 1209.5973 [hep-ph] (lower limit "default" case, upper limit "optimistic" case) High potentiality P5 requirement: 75% at 3σ Neutrino Factory reach 10 years 20 years (courtesy P. Coloma) E. Wildner, CERN

  24. Effect of the unknown MH on CPV performance "default" case for systematics small effect practically no need to re-optimize when MH will be known E. Wildner, CERN

  25. ESS Neutrino Super Beam arXiv:1212.5048 arXiv:1309.7022 14 participating institutes from 10 different countries, among them ESS and CERN EU H2020 Design Study application has been submitted recently !

  26. When and to what price ? • Total price of ESSnuSB including the detector is 1.2 BEUR: • 100 MEUR linac • 200 MEUR accumulator • 200 MEUR target station • 700 MEUR the far detector • If we have our CDR in 2018 and if we convince everybody to build this facilities, we could start construction at the moment when the neutron facility will be ready, i.e., 2023. The construction could last up to 2030-2032 when we will be able to start data taking. • If LBNE starts earlier (e.g. 2029-2030), in one or two years ESSnuSB will accumulate more protons on the target than LBNE. E. Wildner, CERN

  27. Conclusions • For MH and mainly for CP Violation intense neutrino beams are needed. • Better CPV sensitivity at the 2nd oscillation maximum. • EU FP7 LAGUNA-LBNO Design Study is finishing. • The European Spallation Source Linac will be ready in less than 10 years • ESS will have enough protons to go to the 2nd oscillation maximum and increase its CPV sensitivity. • CPV: 5 σ could be reached over 60% of δCP range (ESSνSB) with large potentiality. • Large associated detectors have a rich astroparticle physics program. • Full complementarity with a long baseline experiment on the 1st oscillation maximum using a LAr detector. • A feasibility Design Study for ESSnuSB is now proposed (H2020). E. Wildner, CERN

  28. Backup E. Wildner, CERN

  29. CP Violating Observables atmospheric Non-CP terms solar interference CP violating matter effect ⇒ accessibility to mass hierarchy ⇒ long baseline ≠0 ⇒ CP Violation be careful, matter effects also create asymmetry E. Wildner, CERN

  30. Neutrino Oscillations with "large" θ13 • at the 1st oscillation max.: A=0.3sinδCP • at the 2nd oscillation max.: A=0.75sinδCP 2nd oscillation maximum is better (see arXiv:1310.5992 and arXiv:0710.0554) E. Wildner, CERN

  31. Physics Performance for ESSνSB(Enrique Fernantez, Pilar Coloma) δCP precision (unknown MH) • for 2 GeV • optimum 300-400 km • for 3.5 GeV • optimum 500-600 km • but the variation is small • CPV discovery implies exclusion at 5 σ of 0º and 180º • high δCP resolution around these values is needed • 1º gain around these values increase the discovery δCP range by ~4x5x1º (1st approx.) E. Wildner, CERN

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