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Long Baseline Neutrino Oscillation Experiments
Alfons Weber RAL/University of Oxford RAL -Southampton Meeting RAL February 7, 2003
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Contents Introduction Long baseline experiments The Future SNO KamLAND
SuperKamiokande K2K MINOS OPERA ICARUS The Future Off-Axis Experiments Neutrino Factories A. Weber LBL Experiments
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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! A. Weber LBL Experiments
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Neutrino Mixing Assume that neutrinos do have mass:
mass eigenstates weak interaction eigenstates Analogue to CKM-Matrix in quark sector! Mass eigenstates m1, m2, m3 weak “flavour eigenstates” Unitary mixing matrix: 3 mixing angles & 1 complex phase A. Weber LBL Experiments
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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: A. Weber LBL Experiments
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Oscillation Signature
measures m2 No effect! Smeared by resolution P ~ 1/2 A. Weber LBL Experiments
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The Solar Neutrino Problem
Not enough electron neutrinos from the sun Different detectors (Super-K, Homestake, Gallex, Sage,…) Different detection thresholds All detectors observe neutrino neutrino deficit Reasons: magnetic moment neutrino oscillations Add solar neutrino spectrum A. Weber LBL Experiments
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The SNO Experiment A. Weber LBL Experiments
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Neutrino Reactions in SNO
CC - e p d + n p well measured ne energy spectrum weak angular dependence 1-1/3cos(q) ne only NC x n + p d same cross section for all neutrinos measures total 8B n-flux of the sun ES - + e n x few events mainly sensitive to ne, (less to n and n ) strong angular correlation A. Weber LBL Experiments
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SNO Neutrino flux Fssm = 5.05 Fsno = 5.09 +1.01 -0.81 +0.44 -0.43
+0.46 -0.43 Fsno = 5.09 A. Weber LBL Experiments
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combination of all experimental and solar model information
Interpretation combination of all experimental and solar model information A. Weber LBL Experiments
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KamLAND 1 kton LScint. detector in the Kamioka cavern H2O veto counter
” fast PMTs ” large area PMTs 30% coverage H2O veto counter Multi-hit dead time-less electronics Neutrinos from Japanese nuclear power plants (~160 km) Δm2 sensitivity 710-6eV2 A. Weber LBL Experiments
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KamLAND Collaboration
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 A. Weber LBL Experiments
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Neutrino energy measured
Detecting Neutrinos Large(r) cross-section Specific signature e+ kinetic energy (<8 MeV) 2 annihilation γs (0.5 MeV) neutron capture (2 to 8 MeV) ~2 events / day Neutrino energy measured from positron energy A. Weber LBL Experiments
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So… what does an event look like ?
KamLAND Event So… what does an event look like ? Charge: Red a lot, Blue little Time: Red soon, Blue late A. Weber LBL Experiments
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KamLAND Results Measure rate and energy spectrum of reactor neutrinos
Clear confirmation of LMA A. Weber LBL Experiments
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Atmospheric Neutrinos
Atmosphere is bombarded by cosmic rays Protons (H+) nuclei (He, Li, …) photons … some particles (1&2) produce hadronic shower Neutrino ratio A. Weber LBL Experiments
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The SuperKamiokande Experiment
H2O Cherenkov Detector Proton decay Neutrino interactions A. Weber LBL Experiments
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SuperK Results Atmospheric neutrinos Muon neutrinos are missing!
A. Weber LBL Experiments
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Prototype of a Long-Baseline-Experiments
The K2K Experiment Prototype of a Long-Baseline-Experiments Baseline: 250 km 1020 protons on target E = 12 GeV Neutrino energy: 1.4 GeV A. Weber LBL Experiments
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K2K Results A. Weber LBL Experiments
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The MINOS Experiment NuMI beam to Soudan in MN (distance 735 km)
Sagitta:10 km >1 km wide at destination A. Weber LBL Experiments
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MINOS Detectors There are 3 MINOS Detectors
Near detector @ FNAL (ND) Far detector @ Soudan (FD) Calibration CERN (CalDet) Magn. steel-scintillator-tracking-calorimeter alternating layers of steel and scintillator strips 12 ton 0.9 kton 5.4 kton A. Weber LBL Experiments
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MINOS Far Detector Where? 27. Underground level of the Soudan Underground Mine State Park Operated by the University of MN for the DoE ideal location Tourist attraction: /year well maintained non operated mine Photo by Jerry Meier MINOS cavern in blue A. Weber LBL Experiments
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The MINOS Mural A. Weber LBL Experiments
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Scintillator plane alternating orientations 90o in successive planes
MINOS planes 2-m wide, 0.5-inch thick steel plates Upper steel layer Scintillator plane alternating orientations 90o in successive planes Lower steel layer A. Weber LBL Experiments
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Installation Impressive progress
80% personnel achieve 120% of the work 400+ out of 484 planes are installed normal data taking during installations A. Weber LBL Experiments
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MINOS Oscillation Physics
Several channels to analyse neutrino oscillations T-Test = #CC / #NC ne appearance (q13) Combination of all analysis will reveal mixing parameters Dm2 sin22q flavour hadrons nμ μ nm disappearance 5 m nt appearance hadrons n μ nμ 1.5 m A. Weber LBL Experiments
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nμ CC Energy Analysis Select nμ charge current events and reconstruct neutrino energy Energy resolution: Compare energy spectrum in near and far detector Measure m2 and sin22 range, B field calorimetric m2 sin22 A. Weber LBL Experiments
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μ Disappearance Results
A. Weber LBL Experiments
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First Neutrino Event Upward going Muon! Y t from below from above z
A. Weber LBL Experiments
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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 m2=10-3,sin2(2)=1.0 A. Weber LBL Experiments
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CERN Neutrinos to Grand Sasso
CNGS Beam Baseline: 730km <E > = 17 GeV optimised for neutrino appearance CERN Neutrinos to Grand Sasso Experiments ICARUS OPERA try find by searching for decay kink nuclear emulsion CERN SPS Ep = 400 GeV 4.8*1013 ppp cycle sec 7.6*1019 pot/year A. Weber LBL Experiments
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The OPERA Experiment n m spectrometer n target and t decay detector
Magnetised Iron Dipoles Drift tubes and RPCs ~ 10 m n super module brick (56 Pb/Em. “cells”) 8 cm (10X0) scintillator strips brick wall module n target and t decay detector Each “super-module” is a sequence of 24 “modules” consisting of - a “wall” of Pb/emulsion “bricks” - planes of orthogonal scintillator strips A. Weber LBL Experiments
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Selected bricks extracted daily
OPERA Target Section Sampling by Target Tracker planes ( X,Y ) Brick wall 10 cm Selected brick Event as seen by the target tracker max p.h. 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 A. Weber LBL Experiments
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OPERA Emulsion Brick n 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 n 10X0 ( 56 emulsion films ) 12.5cm 235k bricks for 3 super modules A. Weber LBL Experiments
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OPERA Candidates reconstruct kink topology
“ Long decays reconstruct kink topology “ Short decays detect large impact parameter track Loose cut to reject low momentum tracks A. Weber LBL Experiments
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OPERA: m2 (mixing constrained by SuperK) OPERA
90 % CL limits * m2 ( 10-3 eV2 ) Upper limit Lower limit (U - L) / (2*True) 41 % 19 % 12 % Nτ / year OPERA 90 % CL in 5 years (mixing constrained by SuperK) * assuming the observation of a number of events corresponding to those expected for the given m2 Probability to observe SuperK signal A. Weber LBL Experiments
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Physics Technology Nucleon Decay Atmospheric Neutrinos Solar Neutrinos
Beam Neutrinos (CNGS) Technology Liquid Argon TPC 3D tracking Scintillation light & PMTs trigger readout A. Weber LBL Experiments
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Detail of a long (14 m) m track
2 Drift coord. (m) Full 2D View from the Collection Wire Plane 2 1 3 2 Wire coord. (m) 2 4 6 12 18 1 El.m. shower 2 Zoom views m stop and decay in e Detail of a long (14 m) m track with d-ray spots 3 El.m. shower T600 Pv: Run Evt 12 A. Weber LBL Experiments
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Sensitivity similar to OPERA!
ICARUS Sensitivity atmospheric beam Sensitivity similar to OPERA! A. Weber LBL Experiments
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Sub-dominant Oscillation Modes
Main oscillation mode known solar: atmospheric: Measure sub-dominant oscillation mode P (nm ne) = P1 + P2 + P3 + P4 A. Weber LBL Experiments
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Measuring ne Oscillations
Needs low ne beam contamination narrow band beam (suppresses NC contamination) NuMI Off-Axis Beam already there NC (visible energy), no rejection nm spectrum ne (|Ue32| = 0.01) ne background A. Weber LBL Experiments
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Detector Options Detector on Surface Technologies (low Z) Requirements
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 A. Weber LBL Experiments
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J2K: JHF-SuperK New beam from JAERI Phase I Detector exists! Phase II
50 GeV, 0.77 MW 3.3*1014 ppp / 3.3 sec Phase I approved start operation 2007 Detector exists! Phase II Increase beam power: 4 MW HyperKamiokande: Mton Possibility of measuring CP-violation, if parameters are right! No need for -factory? A. Weber LBL Experiments
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SuperBeam Physics Sensitivity (phase I) CP violation (phase II)
μ disappearance (1 year) CP violation (phase II) A. Weber LBL Experiments
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Neutrino Factory Muon storage ring: The Ultimate Neutrino Source
A. Weber LBL Experiments
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Neutrino Factory Physics
A. Weber LBL Experiments
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Summary Present Future Science fantasy 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) A. Weber LBL Experiments
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