Future neutrino experiments The road-map and a few

Future neutrino experiments The road-map… and a few itineraries Three family oscillations The Japanese way: JPARC SK, HK The alpine way: CERN-SPL … and beta-beam and Fréjus Neutrino Factory Superbeam Neutrino Factory and beta-beam R&D EMCOG statements design studies Conclusions 1

Roadmap Where do we stand? Yo ua re he re Where do we go? Which way do we chose? Shortest? Cheapest? Fastest? Yo u wa nt to go th er e Taking into account practicalities or politics? 2

Where are we? 1. 2. 3. 4. We know that there are three families of active, light neutrinos (LEP) Solar neutrino oscillations are established (Homestake+Gallium+Kam+SK+SNO+Kam. LAND) Atmospheric ( -> ) oscillations are established (IMB+Kam+SK+Macro+Sudan+K 2 K) At that frequency, electron neutrino oscillations are small (CHOOZ) This allows a consistent picture with 3 -family oscillations 12 ~300 Dm 122~7 10 -5 e. V 2 23 ~450 Dm 23 2~ 2. 5 10 -3 e. V 2 with several unknown parameters 13, , mass hierarchy Where do we go? 13 <~ 100 leptonic CP & T violations => an exciting experimental program for at least 25 years *) *)to set the scale: CP violation in quarks was discovered in 1964 and there is still an important program (K 0 pi 0, B-factories, Neutron EDM, LHCb, BTe. V…. ) to go on for >>10 years…i. e. a total of >50 yrs. and we have not discovered leptonic CP yet! 5. LSND ? ( mini. Boo. Ne) This result is not consistent with three families of neutrinos oscillating, and is not supported (nor is it completely contradicted) by other experiments. If confirmed, this would be even more exciting See Barger et al PRD 63 033002 3

The neutrino mixing matrix: 3 angles and a phase 3 Dm 223= 3 10 -3 e. V 2 2 1 Dm 212= 3 10 -5 - 1. 5 10 -4 e. V 2 OR? 2 1 23 (atmospheric) = 450 , 12 (solar) = 300 , 13 (Chooz) < 130 3 Dm 212= 3 10 -5 - 1. 5 10 -4 e. V 2 Dm 223= 3 10 -3 e. V 2 Unknown or poorly known even after approved program: 2 13 , phase , sign of Dm 13 4

1. 27 Dm 2 L / E =p/2 Oscillation maximum Atmospheric Dm 2= 2. 5 10 -3 Solar Dm 2 = 7 10 -5 e. V 2 Latm = 500 km @ 1 Ge. V Lsol = 18000 km @ 1 Ge. V Consequences of 3 Family oscillation : I There will be ↔ e and t ↔ e oscillation at L atm P ( ↔ e )max =~ ½ sin 22 13 +… (small) II There will be CP or T violation CP: P ( ↔ e) ≠ P ( ↔ e) T: P ( ↔ e) ≠ P ( e ↔ ) III we do not know if the neutrino 1 which contains more e is the lightest one (natural? ) or not. 5

P( e ) = ¦A¦ 2+¦S¦ 2 + 2 A S sin P( e ) = ¦A¦ 2+¦S¦ 2 - 2 A S sin P( e ) - P( e ) + P( e ) = ACP a sin (Dm 212 L/4 E) sin 12 sin 13 + solar term… … need large values of sin 12, Dm 212 (LMA) but *not* large sin 2 13 … need APPEARANCE … P( e e) is time reversal symmetric (reactors or sun are out) … can be large (30%) for suppressed channel (one small angle vs two large) at wavelength at which ‘solar’ = ‘atmospheric’ and for e , t … asymmetry is opposite for e and e t 6

! T asymmetry for sin = 1 asymmetry is a few % and requires excellent flux normalization (neutrino fact. , beta beam or off axis beam with neutrino factory JHFII-HK JHFI-SK not-too-near detector) NOTE: This is at first maximum! Sensitivity at low values of 13 is better for short baselines, sensitivity at large values of q 13 may be better for longer baselines (2 d max or 3 d max. ) This would desserve a more careful analysis! 0. 10 0. 30 10 30 90 7

Road Map Experiments to find 13 : 1. search for e in conventional beam (MINOS, ICARUS/OPERA) limitations: NC p 0 background, intrinsic e component in beam 2. Off-axis beam (JHF-SK, off axis NUMI, off axis CNGS) or 3. Low Energy Superbeam (BNL Homestake, SPL Fréjus) Precision experiments to find CP violation -- or to search further if 13 is too small 1. beta-beam 6 He++ 6 Li+++ e e- and 18 Ne 10+ 18 F 9+ e e+ 2. Neutrino factory with muon storage ring + e fraction thereof will exist. and - e 8

Where will this get us… X 5 0. 10 10 2. 50 50 130 Mezzetto comparison of reach in the oscillations; right to left: present limit from the CHOOZ experiment, expected sensitivity from the MINOS experiment, CNGS (OPERA+ICARUS) 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 (J-PARC phase II similar) from a Neutrino Factory with 40 kton large magnetic detector. 9

T 2 K (JPARC Super-Kamiokande) z 295 km baseline z J-PARC approved z neutrino beam under discussion but set as first priority by international committee z Proposal to be submitted early 2004 z Super-Kamiokande: y 22. 5 kton fiducial y Excellent e/ ID -- 10 -3 y Additional 0/e ID -- 10 -2 y (for En~ 500 Me. V- 1 Ge. V) z Matter effects small z need near detector! z 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 Ge. V 10

The (J-PARC- ) p T 2 K Beamline p 0 m 140 m 280 m 2 km 295 km Neutrino spectra at diff. dist 1. 5 km 295 km 280 m 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 11

Schematic drawing of Hyper-Kamiokande 40 m Super-K 1 Mton (fiducial) volume: Total Length 400 m (8 Compartments) Other major goal: improve proton decay reach Supernovae until Andromedes, etc… Excavation will not start until 2011 12

This will be the case in 2011+8+8. 3 = 2027. 3 13

Motivations to go beyond this… 1. Intrinsic limits of conventional neutrino beams (intensity, purity, only , low energy ) 2. Go back to Europe and try to establish a CERN-based program on the long run The common source: SPL physics workshop: 25 -26 May 2004 CERN SPSC Cogne meeting sept. 2004 Superbeam/neutrino Factory design study HIPPI SPL Superbeam Neutrino factory The ultimate tool for neutrino oscillations APEC design study EURISOL Beta beam Very large underground lab Water Cerenkov, Liq. Arg EURISOL design study 14

Possible step 0: Neutrino SUPERBEAM 300 Me. V Neutrinos small contamination from e (no K at 2 Ge. V!) Fréjus underground lab. A large underground water Cerenkov (400 kton) UNO/Hyper. K 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) 15

Europe: SPL Frejus Ge n ev e CERN 130 km SPL @ CERN 2. 2 Ge. V, 50 Hz, 2. 3 x 1014 p/pulse à 4 MW Now under R&D phase 40 kt 400 kt Italy 16

CERN: -beam baseline scenario Nuclear Physics SPL Decay ring Brho = 1500 Tm B=5 T Decay ISOL target & Ion source SPS Lss = 2500 m Ring ECR Cyclotrons, linac or FFAG Rapid cycling synchrotron PS 17

Tunnels and Magnets z Civil engineering costs: Estimate of 400 MCHF for 1. 3% incline (13. 9 mrad) y Ringlenth: 6850 m, Radius=300 m, Straight sections=2500 m z Magnet cost: First estimate at 100 MCHF FLUKA simulated losses in surrounding rock (no public health implications) 18

Detectors Liquid Ar TPC (~100 kton) UNO (400 kton Water Cherenkov) 19

Combination of beta beam with low energy super beam Unique to CERN: need few 100 Ge. V accelerator (PS + SPS will do!) experience in radioactive beams at ISOLDE many unknowns: what is the duty factor that can be achieved? (needs < 10 -3 ) combines CP and T violation tests e ( +) (T) e (p+) (CP) e ( -) (T) e (p-) Can this work? ? theoretical studies now on beta beam + SPL target and horn R&D design study together with EURISOL 20

DUTY FACTOR (this is an issue for low energy superbeam and beta beam) Sub-Ge. V Atmospheric Neutrino interactions are at rate ~100/kt/year. ~ 50% e and 50% For a 500 kton detector this will give 50 000 events of the wrong lepton At this energy the directionality if poor (cuts will not be effective) èIt is necesary to discriminate with timing! èDuty factor required < 10 -3 èSPL (50 Hz), needs 20 microseconds every 20 ms. (accumulator) èBetabeam : needs stacking of ions along the perimeter of the SR. (2 bunches of 10 ns / 7 km) (more bunches of same intensity OK) 21

L. Mosca 22

-- Neutrino Factory -CERN layout 1016 p/s 1. 2 1014 /s =1. 2 1021 /yr 0. 9 1021 /yr 3 1020 e/yr 3 1020 /yr + e _ oscillates e interacts giving - WRONG SIGN MUON interacts giving + 23

Where do you prefer to take shifts? 24

Neutrino fluxes + -> e+ e / e ratio reversed by switching +/ e spectra are different No high energy tail. Very well known flux ( 10 -3) -- E&s. E calibration from muon spin precession -- angular divergence: small effect if < 0. 2/g, - absolute flux measured from muon current or by e- -> - e in near expt. -- in triangle ring, muon polarization precesses and averages out (preferred, -> calib of energy, energy spread) Similar comments apply to beta beam, except spin 0 Energy and energy spread have to be obtained from the properties of the storage ring (Trajectories, RF volts and frequency, etc…) polarization controls e flux: + -X> e in forward direction 25

Detector z Iron calorimeter z Magnetized y Charge discrimination y. B = 1 T z R = 10 m, L = 20 m z Fiducial mass = 40 k. T Also: L Arg detector: magnetized ICARUS Wrong sign muons, electrons, taus and NC evts Baseline 732 Km 3500 Km Events for 1 year CC e CC 3. 5 x 107 5. 9 x 107 1. 2 x 106 2. 4 x 106 *-> signal (sin 2 13=0. 01) 1. 1 x 105 1. 0 x 105 (J-PARC I SK = 40) 26

6 classes of events right sign muon -> + electron/positron -> e+ or e -> ewrong sign muon e -> right sign tau -> t+-> + wrong sign tau e -> t--> - no lepton NC & other taus 27

ICARUS NB: additional potential wrt magnetized iron calorimeter: tau detection, sign of *low* energy electrons, if magnetized. May redefine the optimal parameters of neutrino factory 28

CP asymmetries compare e to e probabilities is prop matter density, positive for neutrinos, negative for antineutrinos HUGE effect for distance around 6000 km!! Resonance around 12 Ge. V when =0 29

CP violation (ctd) Matter effect must be subtracted. One believes this can be done with uncertainty Of order 2%. Also spectrum of matter effect and CP violation is different ÞIt is important to subtract in bins of measured energy. Þknowledge of spectrum is essential here! 5 -10 Ge. V 10 -20 Ge. V 20 -30 Ge. V 30 -40 Ge. V 40 -50 Ge. V 40 kton L M D 50 Ge. V nufact 5 yrs 1021 /yr In fact, 20 -30 Ge. V Is enough! Best distance is 2500 -3500 km e. g. Fermilab or BNL -> west coast or … 30

channel at neutrino factory High energy neutrinos at Nu. Fact allow observation of (wrong sign muons with missing energy and P ). UNIQUE A. Donini et al e t Liquid Argon or OPERA-like detector at 3000 km. Since the sin dependence has opposite sign with the wrong sign muons, this solves ambiguities that will invariably appear if only wrong sign muons are used. ambiguities with only wrong sign muons (3500 km) associating taus to muons equal event number curves (no efficencies, but only OPERA mass) muon vs taus studies on-going 31

Area of phase space in which CP violation can be seen (Mezzetto) NUFACT Superbeam only Beta-beam only Betabeam + superbeam Upgrade 400 kton-> 1 Mton 32

NUFACT Superbeam only Beta-beam only Betabeam + superbeam Upgrade 400 kton-> 1 Mton 33

NUFACT Superbeam only Beta-beam only Betabeam + superbeam Upgrade 400 kton-> 1 Mton J-PARC HK 540 kton? 34

The proposed Roadmap M. Vretenar Consistently with the recent DG talk on the future of CERN, is in preparation a document (“Future Projects and Associated R&D”) to be presented at the December Council. The chapter “Upgrade of the Proton Injector Complex” presents a roadmap, consistent with 2 basic assumptions: • construction of Linac 4 2007/10 (before end of LHC payment) • construction of SPL in 2008/15 (after end of LHC payments) Linac 4 approval SPL approval LHC upgrade 35

L. Mosca This fits very well! 36

Some Critical issues Super beam & Neutrino Factory SPL cost, cleanliness, power limits capability to handle different time structures Accumulation of protons Target and target station Collection (Horn at high radiation and high rep rate) Design/optimization of multihorn system and decay tunel Muon Cooling of large emittance muon beam (MICE + kickers) Fast and cheap accceleration (RF source, FFAG, kickers) Megaton detector Beta beam What size cavity can be dug? cost/time scale Photosensitive devices!!! Ion yields Activation Stacking Do we need a new PS? Other detector (Larg, other) safety…. 37

Motivations to go beyond this… 1. Intrinsic limits of conventional neutrino beams (intensity, purity, only , low energy ) 2. Go back to Europe and try to establish a CERN-based program on the long run The common source: SPL physics workshop: May 2004 CERN SPC Cogne meeting sept. 2004 Superbeam/neutrino Factory design study HIPPI SPL Superbeam Neutrino factory The ultimate tool for neutrino oscillations APEC design study EURISOL Beta beam Very large underground lab Water Cerenkov, L. Arg EURISOL design study 38

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: 39

Superbeam & Beta Beam cost estimates 40

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. 41

1. High intensity proton driver. Activities on the front end are ongoing in many laboratories in Europe, in particular at CERN, CEA, IN 2 P 3, INFN and GSI. Progressive installation of a high intensity injector and of a linear accelerator up to 120 Me. V 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 studies problem 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. (H. Kirk et al) 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. IN 2 P 3 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) 4. Muon Ionization Cooling Never 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 (10 M£). 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. (RF! Cryo? ) More collaboration needed from European institutes outside UK. 42

NUFACT R&D: Target station Experiment @BNL and @CERN z Speed of Hg disruption z Max v 20 m/s measured z v// 3 m/s z jet remains intact for more than 20 microseconds. er uid liq jet m of y cur 1 cm s n roto P 43

US scheme: jet is inside a very high field tapered solenoid (20 T max) this was tested at the Laboratoire de Champs Intenses (Grenoble) A. Fabich et al– CERN-BNL-Grenoble 44

Magnetic horn Current of 300 k. A p To decay channel Protons B=0 Hg Target B 1/R 45

Horn design – not a finished issue Lateral reflector …. To do better : can one place a reflector on the axis – exposed to the 4 MW proton beam power? Question: what is the best proton energy? (can go up to 4 or 5 Ge. V protons with SPL ++) Probably would like to match the beta-beam energy (600 Me. V) Contact S. Gilardoni (Uni. Ge) J. E. Campagne LAL Orsay 46

10% cooling of 200 Me. V/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 Focus coils 1 Focus coils 2 Focus coils 3 Matching coils 1&2 Spectrometer solenoid 2 Beam PID TOF 0 Cherenkov TOF 1 Diffusers 1&2 Incoming muon beam RF cavities 1 RF cavities 2 Liquid Hydrogen absorbers 1, 2, 3 Trackers 1 & 2 measurement of emittance in and out Downstream particle ID: TOF 2 Cherenkov Calorimeter Experiment is now APPRO At RAL. 47

COOLING RINGS Two goals: 1) Reduce hardware expense on cooling channel 2) Combine with energy spread reduction (longitudinal and transverse cooling) major problem: Kickers (Same problem occurs in Japanese acceleration scheme with FFAG) 48

Yoshi Mori NB: a standard cyclotron would be MUCH smaller and inexpensive but would have much smaller acceptance and could not be scaled up to higher energies. 49

SPL Physics workshop 24 -25 May 2004 EMCOG recommended a study of SPL physics opportunities in the framework of the ECFA working groups and BENE (neutrinos + low energy muons + Eurisol + …) Super. Beam/neutrino Factory design study EMCOG fully endorses the proposal and calls for proposals for the R&D experiments. It is stressed that support from the home countries and laboratories is essential to complete the EU funding. Beta-beam design study EMCOG finds this possibility very promising and deserving a thorough study in the best conditions. The subject is very specific and pertinent to a particular site and would justify a separate design study. This has been accepted as a EURISOL work package. EU call for proposal 11 November 2003 Dead line for submission 4 March 2004 Full presentation to community: muon week 16 -19 February 2004 50

Design studies FP 6 foresees funding for design studies of new infrastructures. Encouraged by EU in reference with the (approved) CARE. In preparation ( 4 March 2004) is the proposal for a European based Design study of a Superbeam and Neutrino Factory 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 Design Europe alone does not have critical mass for all this. => world collaboration with USA and Japan was launched at NUFACT 03 in June 2003. 51

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- ! 2. We must however make sure that there is a competitive long term program in Europe ÞSPL is a good start and we must support it very strongly. ÞWithout target, horns etc… it would be however useless for neutrino physics there is a strong physics program with a neutrino superbeam (2015 seems a goal date) and at a later stage beta-beam ÞSPL makes full sense for particle physics as a driver for a neutrino factory There are several severe questions to solve before either can be proposed. design studies with the aim of Conceptual Design Report at LHC/J-Parc start-up 52

Conclusions II After an exciting start in 1998/1999 (NUFACT 99 and NFWG…) we had two difficult years in 2001 -2003. We see now positive signals: -- approval of HIPPI and BENE inside CARE -- SPL seems well on the way -- strong supprt of Dapnia+IN 2 P 3 – INFN for Fréjus Laboratory -- Support and scientific approval of MICE at RAL Next big mountain is success in the Design Study Proposals and of the SPL workshop! good luck to us! 53

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