1. Long Baseline Neutrino Oscillation Experiments Alfons Weber RAL/University of Oxford RAL -Southampton Meeting RAL February 7, 2003

2. A. WeberLBL Experiments2 Contents Introduction Long baseline experiments –SNO –KamLAND –SuperKamiokande –K2K –MINOS –OPERA –ICARUS The Future –Off-Axis Experiments –Neutrino Factories

3. A. WeberLBL Experiments3 Introduction Several indication for neutrino oscillations –Solar neutrino problem Homestake, SAGE, GALLEX Kamiokande, Super-Kamiokande, SNO –Atmospheric neutrino problem Kamiokande, IMB, Frejus, NUSEX, Soudan 2, SuperK –LSND effect LSND, KARMEN New precision experiments are needed! –replace natural with man-made neutrino source –tune oscillation distance and energy to problem Find out what the Neutrino oscillation matrix looks like!

4. A. WeberLBL Experiments4 Neutrino Mixing Assume that neutrinos do have mass: –mass eigenstates  weak interaction eigenstates Analogue to CKM-Matrix in quark sector! weak “flavour eigenstates” Mass eigenstates m 1, m 2, m 3 Unitary mixing matrix: 3 mixing angles & 1 complex phase

5. A. WeberLBL Experiments5 Neutrino Oscillations If mass and weak eigenstates are different: Neutrino is produced in weak eigenstate It travels a distance L as a mass eigenstate It will be detected in a (possibly) different weak eigenstate Simplified model with two neutrinos only:

6. A. WeberLBL Experiments6 Oscillation Signature No effect! measures  m 2 Smeared by resolution P ~ 1/2

7. A. WeberLBL Experiments7 Different detectors (Super-K, Homestake, Gallex, Sage,…) Different detection thresholds All detectors observe neutrino neutrino deficit Reasons: –magnetic moment –neutrino oscillations The Solar Neutrino Problem Not enough electron neutrinos from the sun

8. A. WeberLBL Experiments8 The SNO Experiment

9. A. WeberLBL Experiments9 Neutrino Reactions in SNO NC xx    npd ES --    e e xx - few events - mainly sensitive to e, (less to  and  ) - strong angular correlation - well measured e energy spectrum - weak angular dependence  1-1/3cos(  ) - e only - same cross section for all neutrinos - measures total 8 B -flux of the sun CC - epd  e p

10. A. WeberLBL Experiments10 SNO Neutrino flux  ssm = 5.05 +1.01 -0.81  sno = 5.09 +0.44 -0.43 +0.46 -0.43

11. A. WeberLBL Experiments11 Interpretation combination of all experimental and solar model information

12. A. WeberLBL Experiments12 KamLAND 1 kton LScint. detector in the Kamioka cavern –130017” fast PMTs –700 20” large area PMTs –30% coverage H 2 O veto counter Multi-hit dead time-less electronics Neutrinos from Japanese nuclear power plants (~160 km) Δm 2 sensitivity 7  10 -6 eV 2

13. A. WeberLBL Experiments13 S.Dazeley, K.Eguchi, S.Enomoto, K.Furuno, Y.Gando, J.Goldman, H.Hanada, H.Ikeda, K.Ikeda, K.Inoue, K.Ishihara, W.Ito, T.Iwamoto, H.Kinoshita, T.Kawashima, M.Koga, T.Maeda, T.Mitsui, M.Motoki, K.Nakajima, M.Nakajima, T.Nakajima, I.Nishiyama, H.Ogawa, K.Oki, T.Sakabe, I.Shimizu, J.Shirai, F.Suekane, A.Suzuki, O.Tajima, T.Takayama, K.Tamae, H.Watanabe Tohoku University T.Taniguchi KEK T.Chikamatsu Miyagi Gakuin Women's School H.Higuchi Tohoku-Gakuin University Y-F.Wang IHEP, Beijing J.Busenitz, Z.Djurcic, K.McKinny, D-M.Mei, A.Piepke University of Alabama B.Berger, R.N.Cahn, Y.D.Chan, X.Chen, S.J.Freedman, B.K.Fujikawa, K.T.Lesko, K.-B.Luk, H.Murayama, D.R.Nygren, C.E.Okada, A.W.Poon, H.M.Steiner LBNL/UC Berkeley L.Hannelius, G.A.Horton-Smith, R.D.McKeown, J.Ritter, B.Tipton, P.Vogel California Institute of Technology C.E.Lane Drexel University J.Learned, J.Maricic, S.Matsuno, S.Pakvasa University of Hawaii S.Hatakeyama, R.C.Svoboda Louisiana State University B.D.Dieterle, C.Gregory University of New Mexico J.Detwiler, G.Gratta, H-L.Liew, D.Murphree, N.Tolich, Y. Uchida Stanford University Y.Kamyshkov, W.Bugg, Y.Efremenko, H.Cohn, A.Weidemann, S.Berridge, M.Schram, M.Batygov, Y.Nakamura University of Tennessee L.Braeckeleer, C.Gould, C.L.HoeM.Hornish, H.Karwowski, D.Markoff, J.Messimore, K.Nakamura, R.Rohm, N.Simmons, W.Tornow TUNL KamLAND Collaboration

14. A. WeberLBL Experiments14 Large(r) cross-sectionLarge(r) cross-section Specific signatureSpecific signature e + kinetic energye + kinetic energy (<8 MeV) (<8 MeV) 2 annihilation γ s2 annihilation γ s (0.5 MeV) (0.5 MeV) neutron captureneutron capture (2 to 8 MeV) (2 to 8 MeV) Neutrino energy measured from positron energy Detecting Neutrinos ~2 events / day

15. A. WeberLBL Experiments15 So… what does an event look like ? Time: Red soon, Blue late Charge: Red a lot, Blue little Blue little KamLAND Event

16. A. WeberLBL Experiments16 KamLAND Results Measure rate and energy spectrum of reactor neutrinos Clear confirmation of LMA

17. A. WeberLBL Experiments17 Atmospheric Neutrinos Atmosphere is bombarded by cosmic rays –Protons (H + ) –nuclei (He, Li, …) –photons –… some particles (1&2) produce hadronic shower Neutrino ratio

18. A. WeberLBL Experiments18 The SuperKamiokande Experiment H 2 O Cherenkov Detector –Proton decay –Neutrino interactions

19. A. WeberLBL Experiments19 SuperK Results Atmospheric neutrinos Muon neutrinos are missing!

20. A. WeberLBL Experiments20 The K2K Experiment Baseline: 250 km 10 20 protons on target E = 12 GeV Neutrino energy: 1.4 GeV Prototype of a Long-Baseline-Experiments

21. A. WeberLBL Experiments21 K2K Results

22. A. WeberLBL Experiments22 NuMI beam to Soudan in MN (distance 735 km) Sagitta:10 km >1 km wide at destination The MINOS Experiment

23. A. WeberLBL Experiments23 MINOS Detectors There are 3 MINOS Detectors –Near detector @ FNAL (ND) –Far detector @ Soudan (FD) –Calibration detector@ CERN (CalDet) Magn. steel-scintillator-tracking-calorimeter –alternating layers of steel and scintillator strips 5.4 kton 12 ton 0.9 kton

24. A. WeberLBL Experiments24 Photo by Jerry Meier Where? 27. Underground level of the Soudan Underground Mine State Park Operated by the University of MN for the DoE ideal location Tourist attraction: 40.000/year well maintained non operated mine MINOS cavern in blue MINOS Far Detector

25. A. WeberLBL Experiments25 The MINOS Mural

26. A. WeberLBL Experiments26 Upper steel layer Lower steel layer Scintillator plane alternating orientations  90 o in successive planes 2-m wide, 0.5-inch thick steel plates MINOS planes

27. A. WeberLBL Experiments27 Installation Impressive progress –80% personnel achieve 120% of the work –400+ out of 484 planes are installed –normal data taking during installations

28. A. WeberLBL Experiments28 Several channels to analyse neutrino oscillations – T-Test = #CC / #NC – – e appearance (    – Combination of all analysis will reveal mixing parameters –  m 2 – sin 2 2  – flavour  appearance   disappearance μ μ hadrons 5 m μ hadrons μ 1.5 m MINOS Oscillation Physics

29. A. WeberLBL Experiments29 Select μ charge current events and reconstruct neutrino energy Energy resolution: Compare energy spectrum in near and far detector Measure  m 2 and sin 2 2  range, B fieldcalorimetric m2m2 sin 2 2  μ CC Energy Analysis

30. A. WeberLBL Experiments30  μ Disappearance Results

31. A. WeberLBL Experiments31 First Neutrino Event Y z t from abovefrom below Upward going Muon!

32. A. WeberLBL Experiments32 Atmospheric Neutrinos Look for high energy muons (>1 GeV) 4 years of data taking (18 kton years) measure stopping and through- going muons Energy measurement by magnetic field Separation of neutrinos and anti-neutrinos! un-oscillated spectrum  m 2 =10 -3,sin 2 (2  )=1.0

33. A. WeberLBL Experiments33 CERN SPS –E p = 400 GeV –4.8*10 13 ppp –cycle 6 - 27.6 sec –7.6*10 19 pot/year Baseline: 730km = 17 GeV optimised for  neutrino appearance CNGS Beam CERN Neutrinos to Grand Sasso Experiments –ICARUS –OPERA –try find  by searching for decay kink –nuclear emulsion

34. A. WeberLBL Experiments34 ~ 10 m  spectrometer Magnetised Iron Dipoles Drift tubes and RPCs target and  decay detector Each “super-module” is a sequence of 24 “modules” consisting of - a “wall” of Pb/emulsion “bricks” - planes of orthogonal scintillator strips scintillator strips brick wall modul e brick (56 Pb/Em. “cells”) 8 cm (10X 0 ) super module The OPERA Experiment

35. A. WeberLBL Experiments35 Emulsion-Scintillator strip Hybrid Target Tracker task select bricks efficiently High scanning power + low background allow coarse tracking Selected bricks extracted daily using dedicated robot Sampling by Target Tracker planes ( X,Y ) Brick wall 10 cm Selected brick OPERA Target Section

36. A. WeberLBL Experiments36 Origami packed ECC brick for OPERA Vacuum packing Protection against light and humidity variations. Keep the position between films and lead plates. Vacuum preserved over 10 years 10X 0 ( 56 emulsion films ) 12.5cm 235k bricks for 3 super modules OPERA Emulsion Brick

37. A. WeberLBL Experiments37 “ Long decays  reconstruct kink topology “ Short decays  detect large impact parameter track Loose cut to reject low momentum tracks OPERA   Candidates

38. A. WeberLBL Experiments38 OPERA 90 % CL in 5 years OPERA:  m2 * assuming the observation of a number of events corresponding to those expected for the given  m 2 (mixing constrained by SuperK) Probability to observe SuperK signal 90 % CL limits *  m 2 ( 10 -3 eV 2 ) 1.5 3.2 5.0 Upper limit 2.1 3.8 5.6 Lower limit 0.8 2.6 4.3 (U - L) / (2*True) 41 % 19 % 12 % N τ / year 0.82 2.82 3.66

39. A. WeberLBL Experiments39 Physics –Nucleon Decay –Atmospheric Neutrinos –Solar Neutrinos –Beam Neutrinos (CNGS) Technology –Liquid Argon TPC –3D tracking –Scintillation light & PMTs trigger readout

40. A. WeberLBL Experiments40 2 El.m. shower Full 2D View from the Collection Wire Plane 2461812 Wire coord. (m) 2 Drift coord. (m) Zoom views 1 3 2 2 3  stop and decay in e Detail of a long (14 m)  track with  -ray spots El.m. shower T600 test @ Pv: Run 201 - Evt 12 1

41. A. WeberLBL Experiments41 ICARUS Sensitivity atmosphericbeam Sensitivity similar to OPERA!

42. A. WeberLBL Experiments42 Sub-dominant Oscillation Modes Main oscillation mode known – solar: – atmospheric: Measure sub-dominant oscillation mode P (   e ) = P 1 + P 2 + P 3 + P 4

43. A. WeberLBL Experiments43 Measuring e Oscillations Needs –low e beam contamination –narrow band beam (suppresses NC contamination) NuMI Off-Axis –Beam already there e (|U e3 2 | = 0.01) e background NC (visible energy), no rejection  spectrum

44. A. WeberLBL Experiments44 Detector Options Detector on Surface –but 10 -5 duty factor Technologies (low Z) –MegaMINOS –Liquid Scintillator –Liquid Argon –RPCs Requirements –good sampling –max: mass/radiation length –CHEAP!!!!! (20 kton, 400k ch) Physics reach –oscillation probability around 10 -3 electron = fuzzy track

45. A. WeberLBL Experiments45 J2K: JHF-SuperK Phase II –Increase beam power: 4 MW –HyperKamiokande: 1 Mton Possibility of measuring CP-violation, if parameters are right! No need for  -factory? New beam from JAERI –50 GeV, 0.77 MW –3.3*10 14 ppp / 3.3 sec Phase I –approved –start operation 2007 Detector exists!

46. A. WeberLBL Experiments46 SuperBeam Physics CP violation (phase II) Sensitivity (phase I) –  μ disappearance (1 year)

47. A. WeberLBL Experiments47 Neutrino Factory Muon storage ring: The Ultimate Neutrino Source

48. A. WeberLBL Experiments48 Neutrino Factory Physics

49. A. WeberLBL Experiments49 Summary Present –K2K (re-starting now) –KamLAND(one year of data taking) Future –MINOS(cosmics 2001, beam 2005) –OPERA(beam 2007) –ICARUS(2005, partially approved) –JHF-SuperK(2007, not yet approved) –NuMI off-axis(beam 2005, detector 2007+) Science fantasy –Neutrino Factories(2010, at the earliest)