Consequences of 3 Family oscillation:

1. Oscillation maximum 1.27 Dm2 L / E =p/2 Atmospheric Dm 2= 2.5 10-3 eV 2 L = 500 km @ 1 GeV Solar Dm2 = 7 10-5 eV2 L = 18000km @ 1 GeV Consequences of 3 Family oscillation: I There will be nm↔ ne and nt ↔ ne oscillation at L atm P (nm↔ ne)max =~ ½ sin 22 q13+… (small) II There will be CP or T violation CP: P (nm↔ ne) ≠ P (nm↔ ne) T : P (nm↔ ne) ≠ P (ne ↔nm) III we do not know if the neutrino n1 which contains more ne is the lightest one (natural?) or not.

2. LEPTONIC T , CP VIOLATION The baryon asymmetry in the Universe… requires CP or T violation. That of the quarks is not enough! Boris Kayser This leptonic asymmetry would in turn generate baryon asymmetry. (energies typical of the particles that would be exchanged in Baryon decay 1015 GeV or so) NB this is CP asymmetry for the Heavy Majorana Neutrinos 1. we don’t know if neutrinos are Majorana particles 2. The CP phases that enter are those of the heavy neutrinos, not the light ones. Nevertheless: leptonic CP violation may be the reason why we exist… lets look for it!

3. Where will this get us… 0.10 130 2.50 50 10 Mezzetto sin213 comparison of reach in the oscillations; right to left: present limit from the CHOOZ experiment, expected sensitivity from the MINOS experiment, 0.75 MW JHF to super Kamiokande with an off-axis narrow-band beam, Superbeam: 4 MW CERN-SPL to a 400 kton water Cerenkov in Fréjus from a Neutrino Factory with 40 kton large magnetic detector. INCLUDING SYSTEMATICS

4. JHF  Super-Kamiokande • 295 km baseline • J-PARC approved • neutrino beam under discussion but set as first priority by international committee • Proposal to be submitted early 2004 • Super-Kamiokande: • 22.5 kton fiducial • Excellent e/ ID -- 10-3 • Additional 0/e ID -- 10-2 • (for En~ 500 MeV- 1 GeV) • Matter effects small • need near detector! • European collaboration forming (mailing list: UK(5)-Italy(5)-Saclay-Gva-ETHZ- Spain(2)) This experiment is at the right ratio of Energy to distance Lmax = 300 km at 0.6 GeV

5. Detector Phase I: the Super Kamiokande Detector

6. /e Background Rejection e/m separation directly related to granularity of coverage. Limit is around 10-3 (mu decay in flight) SKII coverage OKOK, less maybe possible

7. p p n 0 m 140 m 280 m 2 km 295 km The J-PARC-n Beamline Neutrino spectra at diff. dist Problem with water Cerenkov: not very sensitive to details of interactions. Either 280 m or 2 km would be good locations for a very fine grained neutrino detector Planned: a scintillating fiber/water calorimeter. Liquid argon TPC would be a very good (better) candidate! Event numbers: near/SK = m(near[tons]) / 22500 . (300/2)2 = m(near[tons]) => Need 10-50 tons fiducial or so 1.5km 295km 280m

8. Schematic drawing of Hyper-Kamiokande Super-K 40m 1 Mton (fiducial) volume: Total Length 400m (8 Compartments) Other major goal: improve proton decay reach Supernovae until Andromedes, etc…

9. Motivations to go beyond this… • Intrinsic limits of conventional neutrino beams (intensity, purity, only nm , low energy ) • Go back to Europe and try to establish a possible CERN-based program on the long run The common source: SPL SPL physics workshhop: June 2004  CERN SPC Cogne meeting sept.2004 Neutrino factory The ultimate tool for neutrino oscillations Superconducting Proton Linac SPL Superbeam Very large underground lab Water Cerenkov, L.Arg Beta beam EURISOL High intensity Low energy muon beams

10. -- Neutrino Factory --CERN layout 1016p/s 1.2 1014 m/s =1.2 1021 m/yr _ 0.9 1021 m/yr m+ e+ne nm 3 1020 ne/yr 3 1020 nm/yr oscillates ne nm interacts givingm- WRONG SIGN MUON interacts giving m+

11. Possible step 0: Neutrino SUPERBEAM 300 MeV n m Neutrinos small contamination from ne (no K at 2 GeV!) Fréjus underground lab. A large underground water Cerenkov (400 kton) UNO/HyperK or/and a large L.Arg detector. also : proton decay search, supernovae events solar and atmospheric neutrinos. Performance similar to J-PARC II There is a window of opportunity for digging the cavern stating in 2008 (safety tunnel in Frejus)

12. Europe: SPLFrejus CERN Geneve • SPL @ CERN • 2.2GeV, 50Hz, 2.3x1014p/pulse • 4MW Now under R&D phase 130km 40kt 400kt Italy

13. Neutrino Factory studies and R&D USA, Europe, Japan have each their scheme. Only one has been costed, US study II: + detector: MINOS * 10 = about 300 M€ or M$ Neutrino Factory CAN be done…..but it is too expensive as is. Aim: ascertain challenges can be met + cut cost in half.

14. EMCOG (European Muon Concertation and Oversight Group) • FIRST SET OF BASIC GOALS • The long-term goal is to have a Conceptual Design Report for a European Neutrino Factory Complex by the time of JHF & LHC start-up, so that, by that date, this would be a valid option for the future of CERN. • An earlier construction for the proton driver (SPL + accumulator & compressor rings) is conceivable and, of course, highly desirable. • The SPL and targetry and horn R&D have therefore to be given the highest priority. • Cooling is on the critical path for the neutrino factory itself; there is a consensus that a cooling experiment is a necessity. • The emphasis should be the definition of • practical experimental projects with a duration of 2-5 years. • Such projects can be seen in the following four areas:

15. High intensity proton driver. Activities on the front end are ongoing in many laboratories in Europe, in particular at CERN, CEA, IN2P3, INFN and GSI. Progressive installation of a high intensity injector and of a linear accelerator up to 120 MeV at CERN (R. Garoby et al) would have immediate rewards in the increase of intensity for the CERN fixed target program and for LHC operation. This (HIPPI) has received funding from EU! • 2.Target studiesproblem at 4 MW!! • . This experimental program is underway with liquid metal jet studies. Goal: explore synergies among the following parties involved: CERN, Lausanne, Megapie at PSI, EURISOL, etc… • Experiment at CERN under consideration by the collaboration. • 3.Horn studies.Problem at 50 Hz and 4 MW • A first horn prototype has been built and pulsed at low intensity. Mechanical properties measured (S. Gilardoni’s thesis, GVA) • 5 year program to reach high intensity, high rep rate pulsing, and study the radiation resistance of horns. Optimisation of horn shape. IN2P3 Orsay has become leading house for this. Collaborations to be sought with Saclay, PSI (for material research and fatigue under high stress in radiation environment) • Muon Ionization CoolingNever done! • A collaboration towards and International cooling experiment MICE has been established with the muon collaboration in United States and Japanese groups. There is a large interest from European groups in this experiment. Following the submission of a letter of Intent to PSI and RAL, the collaboration has prepared a full proposal at RAL. • Proposal has been strongly encouraged and large UK funding secured (10M£). • PSI offers a solenoid for the muon beam line • CERN, which as already made large initial contributions in the concept of the experiment, • has earmarked some very precious hardware that could be recuperated.

16. What muon cooling buys MUON Yield without and with Cooling exact gain depends on relative amont of phase rotation (monochromatization vs cooling trade off) cooling of minimum ionizing muons has never been realized in practice involves RF cavities, Liquid Hydrogen absorbers, all in magnetic field designs similar in EU and US Nufact concepts

17. IONIZATION COOLING principle: reality (simplified) this will surely work..! ….maybe… DARK current & RF NOISE!!? A delicate balance between energy loss and multiple scattering, & a technological challenge Difficulty: Wide aperture -> expensive. Affordable prototype of cooling section only cools beam by 10%, while standard emittance measurements barely achieve this precision. Solution: measure the beam particle-by-particle

18. n An International Muon Ionization Cooling Experiment p m MICE

19. 10% cooling of 200 MeV/c muons requires ~ 20 MV of RF single particle measurements => measurement precision can be as good as D ( e out/e in ) = 10-3 never done before either…. Coupling Coils 1&2 Spectrometer solenoid 1 Matching coils 1&2 Matching coils 1&2 Spectrometer solenoid 2 Focus coils 1 Focus coils 2 Focus coils 3 m Beam PID TOF 0 Cherenkov TOF 1 RF cavities 1 RF cavities 2 Downstream particle ID: TOF 2 Cherenkov Calorimeter Diffusers 1&2 Liquid Hydrogen absorbers 1,2,3 Incoming muon beam Trackers 1 & 2 measurement of emittance in and out

20. We propose a Swiss contribution to the International Muon Ionization Cooling Experiment MICE -- part of international concerted effort -- the Swiss collaborators play an essential role in the design of the experiment and in its leadership. -- well matched to the competence of experimental particle physicists -- will lead to first experimental observation of ionization cooling. -- + detailed study of various absorbers, optics, and limits of accelerating gradient. => PSI will provide a muon beam solenoid. => Spectrometer (tracker and contribution to spectrometer solenoid) 720 kCHF => Collaborate with CERN to provide RF power source, based on equipment available at CERN (well justified geographically, maintains ties with CERN without asking CERN the impossible) Cant FORCE funds be allocated for this? Est 760 kCHF Submitted as SNF request with funding profile for 5 years. As a starting point for discussion. Total (including common funds, maintenance, travel and 2 PhD + 2 MA) 3.2 MCHF

21. MICE tracker option: TPC with GEM readout. 250 microns pads connected in 3 sets of strips 1st Prototype being built will take data by end october.

23. Design studies FP6 foresees funding for design studies of new infrastructures. Encouraged by EU in reference with the (approved) CARE. In preparation is the proposal for a European based Design study of a neutrino factory and superbeam RAL as leading house. (Peach/Edgecock) Proton driver CERN in coll. With RAL, etc., Target  many interested. Still searching a leading house. (PSI not interested?) TTA at CERN under consideration. (pulsed beam important) Horn and collectors LAL orsay Cooling; MICE Acceleration, FFAG Saclay, Grenoble Storage ring and instrumentation NN. Europe alone does not have critical mass for all this. => world collaboration with USA and Japan was launched at NUFACT03 in June 2003.

24. Conclusions • Neutrino Physics is alive an attractive. • We have an exciting program for many years. •  discovery and studies of leptonic CP violation • This addresses very fundamental questions (GUTS, matter asymmetry, masses) • from a completely different viewpoint than the energy frontier. • 1. We should not miss the opportunity to make a coherent contribution to JPARC-n! • 2. We must however make sure that there is a competitive long term program in Europe • (and at CERN preferably) • SPL is a good start and we must support it very strongly. • Without target, horns etc… it would be however useless. • And it makes full sense for particle physics as a driver for a neutrino factory • Support neutrino factory R&D: MICE and collaborations with e.g. target experiment, etc…

25. RESERVE

26. Designing a superbeam experiment • The process to be detected for superbeam nmexperiments is appearance of ne • ne + N -> e- X event with an electron in the final state. • backgrounds: • 1.ne contamination in the beam from • m+ e+nenmK+ e+nep0K0L e+nep- • 2.p0production in Neutral Current events. • solutions: 1. detector must separate electrons from muons • 2. beam must be as pure and as monochromatic as possible or: • 2’. avoid K production by using low energy proton source • 3. stay at low energy (~< 0.6 GeV)to avoid p0production • flux (E2 /L2) X cross-section (E) goes like E3 /L2 • on first oscillation: • oscillation goes like (L/E)2 =>oscillated signal goes like E • background goes as E3 /L2 => go far to avoid background ( => around 1st maximum) • on subsequent oscillations: • flux and signal decrease, signal/noise does not improve, • to be avoided unless it provides complementary information– to be demonstrated

27. Charged current cross sections data are old, sparce and sometimes ambiguous. • Inelastic • NCp0 • multi p • …. CCqe dominate ≲1GeV Inelastic dominate ≳1GeV Background CCqe (nm+nm+p)

28. (Super) Neutrino Beams

29. T asymmetry for sin  = 1 ! asymmetry is a few % and requires excellent flux normalization (neutrino fact. or off axis beam with not-too-near near detector) ! neutrino factory JHFII-HK JHFI-SK 10 30 0.10 0.30 90

30. Detectors at near site • Muon monitors @ ~140m • Behind the beam dump • Fast (spill-by-spill) monitoring of beam direction/intensity • First Front detector “Neutrino monitor” @280m • Intensity/direction • Neutrino interactions • Second Front Detector @ ~2km • Almost same En spectrum as for SK • Absolute neutrino spectrum • Precise estimation of background • Investigating possible sites Neutrino spectra at diff. dist 1.5km 295km 280m

31. Syst. error: far/near spectrum diff. Typical OA beam(80mDV) 295km 280m K2K case (MC) FD(300m) (xLSK2/LFD2) SK Large(~x2) effect around peak!! Important not only for nm disappearance, but also for sig/BG estimation for ne search