490 likes | 657 Vues
Long Baseline Neutrino Oscillation Experiments. Alfons Weber RAL/University of Oxford RAL -Southampton Meeting RAL February 7, 2003. Contents . Introduction Long baseline experiments SNO KamLAND SuperKamiokande K2K MINOS OPERA ICARUS The Future Off-Axis Experiments
E N D
Long Baseline Neutrino Oscillation Experiments Alfons WeberRAL/University of OxfordRAL -Southampton Meeting RAL February 7, 2003
Contents • Introduction • Long baseline experiments • SNO • KamLAND • SuperKamiokande • K2K • MINOS • OPERA • ICARUS • The Future • Off-Axis Experiments • Neutrino Factories LBL Experiments
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! LBL Experiments
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 LBL Experiments
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: LBL Experiments
Oscillation Signature measures m2 No effect! Smeared by resolutionP ~ 1/2 LBL Experiments
The Solar Neutrino Problem • Different detectors (Super-K, Homestake, Gallex, Sage,…) • Different detection thresholds • All detectors observe neutrinoneutrino deficit • Reasons: • magnetic moment • neutrino oscillations Not enough electron neutrinos from the sun LBL Experiments
The SNO Experiment LBL Experiments
n + + + - CC d p e e n + + + n NC d p n x x ES - - + + n e n e x x Neutrino Reactions in SNO p • well measured ne energy spectrum • weak angular dependence 1-1/3cos(q) • ne only • same cross section for all neutrinos • measures total 8B n-flux of the sun • few events • mainly sensitive to ne, (less to n and n ) • strong angular correlation LBL Experiments
+1.01 Fssm = 5.05 -0.81 +0.44 +0.46 -0.43 -0.43 SNO Neutrino flux • Fsno = 5.09 LBL Experiments
Interpretation combination of all experimental and solar model information LBL Experiments
KamLAND • 1 kton LScint. detector in the Kamioka cavern • 1300 17” fast PMTs • 700 20” 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 LBL Experiments
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 LBL Experiments
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 LBL Experiments
KamLAND Event So… what does an event look like ? Charge: Red a lot, Bluelittle Time: Red soon, Blue late LBL Experiments
Measure rate and energy spectrum of reactor neutrinos Clear confirmation of LMA KamLAND Results LBL Experiments
Atmospheric Neutrinos • Atmosphere is bombarded by cosmic rays • Protons (H+) • nuclei (He, Li, …) • photons • … • some particles (1&2) produce hadronic shower • Neutrino ratio LBL Experiments
The SuperKamiokande Experiment • H2O Cherenkov Detector • Proton decay • Neutrino interactions LBL Experiments
SuperK Results • Atmospheric neutrinos • Muon neutrinos are missing! LBL Experiments
Baseline: 250 km 1020 protons on target E = 12 GeV Neutrino energy: 1.4 GeV The K2K Experiment Prototype of a Long-Baseline-Experiments LBL Experiments
K2K Results LBL Experiments
The MINOS Experiment • NuMI beam to Soudan in MN (distance 735 km) • Sagitta:10 km • >1 km wide at destination LBL Experiments
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 12 ton 0.9 kton 5.4 kton LBL Experiments
Photo by Jerry Meier MINOS Far Detector • Where? 27. Underground level of the Soudan Underground Mine State Park • Operated by theUniversity of MN for the DoE • ideal location • Tourist attraction: 40.000/year • well maintained • non operated mine MINOS cavern inblue LBL Experiments
The MINOS Mural LBL Experiments
MINOS planes 2-m wide, 0.5-inch thick steel plates Upper steel layer Scintillator planealternating orientations90o in successive planes Lower steel layer LBL Experiments
Installation • Impressive progress • 80% personnel achieve 120% of the work • 400+ out of 484 planes are installed • normal data taking during installations LBL Experiments
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 nμ nμ 1.5 m LBL Experiments
Select nμ charge current events and reconstruct neutrino energy Energy resolution: Compare energy spectrum in near and far detector Measure m2 and sin22 nμ CC Energy Analysis range, B field calorimetric m2 sin22 LBL Experiments
μDisappearance Results LBL Experiments
First Neutrino Event Upward going Muon! Y t from below from above z LBL Experiments
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 LBL Experiments
CERN SPS Ep = 400 GeV 4.8*1013 ppp cycle 6 - 27.6 sec 7.6*1019 pot/year Baseline: 730km <E> = 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 LBL Experiments
m spectrometer Magnetised Iron Dipoles Drift tubes and RPCs brick (56 Pb/Em. “cells”) n ~ 10 m 8 cm (10X0) 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 brick wall scintillator strips The OPERA Experiment super module LBL Experiments
Selected brick Sampling by Target Tracker planes ( X,Y ) Brick wall Event as seen by the target tracker 10 cm p.h. 0 max OPERA Target Section • 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 LBL Experiments
OPERA Emulsion Brick Origami packed ECC brick for OPERA • Vacuum packing • Protection against light and humidity variations. • Keep the positionbetweenfilms and lead plates. • Vacuum preserved over 10 years n 10X0 ( 56 emulsion films ) 12.5cm 235k bricks for 3 supermodules LBL Experiments
OPERA Candidates “ Long decays reconstruct kink topology “ Short decays detect large impact parameter track Loose cut to reject low momentum tracks LBL Experiments
90 % CL limits * m2 ( 10-3 eV2 ) 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 % Nτ / year 0.822.82 3.66 OPERA 90 % CL in 5 years OPERA: m2 (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 LBL Experiments
Physics • Nucleon Decay • Atmospheric Neutrinos • Solar Neutrinos • Beam Neutrinos (CNGS) • Technology • Liquid Argon TPC • 3D tracking • Scintillation light & PMTs trigger readout LBL Experiments
Full 2D View from the Collection Wire Plane 2 Drift coord. (m) 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 test @ Pv: Run 201 - Evt 12 LBL Experiments
ICARUS Sensitivity atmospheric beam Sensitivity similar to OPERA! LBL Experiments
Sub-dominant Oscillation Modes • Main oscillation mode known • solar: • atmospheric: • Measure sub-dominant oscillation mode P (nm ne) = P1 + P2 + P3 + P4 LBL Experiments
Measuring ne Oscillations • Needs • low ne beam contamination • narrow band beam (suppresses NC contamination) • NuMI Off-Axis • Beam already there ne background NC (visible energy), no rejection nm spectrum ne (|Ue32| = 0.01) LBL Experiments
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 probabilityaround 10-3 electron = fuzzy track LBL Experiments
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*1014 ppp / 3.3 sec Phase I approved start operation 2007 Detector exists! J2K: JHF-SuperK LBL Experiments
CP violation (phase II) Sensitivity (phase I) μ disappearance (1 year) SuperBeam Physics LBL Experiments
Neutrino Factory • Muon storage ring: The Ultimate Neutrino Source LBL Experiments
Neutrino Factory Physics LBL Experiments
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) LBL Experiments