Long Baseline Neutrino Oscillation...
Transcript of Long Baseline Neutrino Oscillation...
Long Baseline Neutrino Oscillation Experiments
Alfons WeberUniversity of Oxford
XXXVIIth Recontre de Moriond
"Electroweak Interactions and Unified Theories"
Les Arcs, Savoie, France March 9-16, 2002
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Contents• Introduction• Long baseline experiments
– K2K– MINOS– OPERA– ICARUS– KamLAND
• The Future– SuperBeams– Neutrino Factories
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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
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Neutrino Oscillations12 13 13 12 13 1
23 12 12 13 23 12 23 12 13 23 13 23 2
23 12 12 23 13 12 23 23 12 13 13 23 3
ei i
i i
c c c s sc s e c s s c c e s s s c s
s s e c c s c s e c s s c c
δ δµ
δ δτ
ν νν νν ν
= − − − − − −
24 2 23
13 23
1.27( ) cos ( )sin ( )sin
m LP
Eµ τν
ν ν θ θ ∆
→ =
Disappearance of atmospheric muon neutrinos:
6 parameter to be determined:•3 angle•2 mass differences•1 CP violating phase
difference mass and angle mixing ,sin ),cos(with 2ij ==== ijijijijij ?m?)(?sc θ
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K2K
• Distance: 250 km• Beam Energy: 12 GeV• Neutrino Energy: 1.3 GeV
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MINOS
• Beam travels 730 km toSoudan Minnesota
• FNAL Main Injector– E = 120 GeV – 4x1013 ppp (?)– Cycle 2 sec– 10 µsec spill
• Tuneable neutrino Energy– Peak at: 3, 7, 15 GeV
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IHEP-Beijing lCollege de France l Athens l Dubna l ITEP-Moscow l Lebedev l ProtvinoCambridge l Oxford l Rutherford l Sussex l University College London
Argonne l Brookhaven l Caltech l Chicago l Elmhurst l Fermilab l James Madison l
Harvard l Illinois l Indiana l Livermore l Macalester l Minnesota l Northwestern l
Pittsburgh l South Carolina l Stanford l Texas-Austin lTexas A&M lTufts lWestern Washington l Wisconsin
Around 180 Physicists and Engineers
MINOS Collaboration
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• 2 Super-modules 2.7 kiloton each
• 486 planes of steel and scintillator
• 96 scintillator stripseach plane
• double sided read-outwith multi-anode PMTs
• Toroidal magnetic field(1.5 T at 2 m radius)
• Very similar near detector!
MINOS Far Detector
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8 m
Scintillator Module
WLS
Fib
ers
WLS
Fib
ers
Optical Connector
Optical Connector
Optical Connector
Optical Connector
Cle
ar F
iber
Rib
bon
Cab
le (2
-6 m
)
MultiplexBox
MultiplexBox
PMTs
Con
nect
ion
to
elec
troni
cs
Con
nect
ion
to
elec
troni
cs
MINOS Scintillator Module• 4-8m
scintillator modules
• 24-28 strips• double sided
readout• multi anode
PMTs (16/64)
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Bottom steel plane layerTop steel plane layerScintillator plane
Orientations alternate ±90o
in successive planes
2-m wide, 0.5-inch thicksteel plates
MINOS Plane
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• Several channels to analyse neutrino oscillations– T-Test = #CC / #NC–– νe appearance (θ13)–
• Combination of all analysis will reveal mixing parameters– ∆m2
– sin22θ– flavour
ντ appearance
νµ disappearance
µ? µ
hadrons
5 m
? µ
hadrons
? µ
1.5 m
MINOS Oscillation Physics
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• Select ?µ charge current events and reconstruct neutrino energy
• Energy resolution:
• Compare energy spectrum in near and far detector
• Measure ? m2 and sin22?
hEEE += µν
range, B field calorimetry
EEE
pp
hh /%60/
%10/
=∆
=∆ µµ
? m2
sin22?
?µ CC Energy Analysis
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?µ Disappearance Results
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• 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 t
appearance
CNGS Beam
CERN Neutrinos to Grand Sasso
• Experiments– ICARUS– OPERA
– try find t by searching for decay kink
– nuclear emulsion
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29 groups~ 130 physicists
METU, Ankara, Turkey • LAPP and Université de Savoie, Annecy, France •INFN and Bari University, Bari, Italy • IHEP, Beijing, China PR • Humboldt University,Berlin, Germany • Bern University, Bern, Switzerland • INFN and
Bologna University, Bologna, Italy • IIHE (ULB-VUB), Brussels, Belgium • Joint Institute for Nuclear Research (JINR), Dubna, Russia • Laboratori Nazionali di
Frascati, INFN Frascati, Italy • Toho University, Funabashi, Japan • CERN, Geneva, Switzerland • Märkische Fachhochschule FB Elektrotechnik, Hagen,
Germany • Technion, Haifa, Israel • Hamburg University, Hamburg, Germany •High Energy Physics Group Shandong University, Jinan, Shandong, China PR •Aichi Educational University, Kariya, Japan • Kobe University, Kobe, Japan •
IPNL and Université C.Bernard, Lyon, France • INR, ITEP and MEPHI, Moscow, Russia • Münster University, Münster, Germany • Nagoya University, Nagoya, Japan • INFN and "Federico II" University, Naples, Italy • LAL and
Université Paris-Sud, Orsay, France • INFN and Padova University, Padova, Italy • INFN and "La Sapienza" University, Rome, Italy • Rostock University, Rostock, Germany • INFN and Salerno University, Salerno, Italy • IRES,
Strasbourg, France • Utsunomiya University, Utsunomiya, Japan • Rudjer Boskovic Institute (IRB), Zagreb, Croatia
OPERA Collaboration
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~ 10
mν
µ spectrometerMagnetised Iron Dipoles
Drift tubes and RPCs
ν target and τ decay detectorEach “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
module
brick(56 Pb/Em. “cells”)
8 cm (10X0)
super module
The OPERA Experiment
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Emulsion-Scintillator strip Hybrid Target
•Tracker taskselect bricks efficiently
• High scanning power + low background allow coarse tracking
Selected bricks extracted dailyusing dedicated robot
Sampling by Target Tracker planes ( X,Y )
Brick wall
10 c
m
Selected brick
Event as seen by the target tracker
0 max
p.h.
OPERA Target Section
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ν
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
10X0 ( 56 emulsion films )
12.5cm235k bricks for 3 super modules
OPERA Emulsion Brick
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“ Long decays″reconstruct kink topology
“ Short decays ″detect large impact parameter track
Loose cut to reject low momentum tracks
OPERA ?t Candidates
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∆m2 = 1.2x10-3 eV2
at full mixing
sin2 (2θ) = 6.0x10-3
at large ∆m2
(average 90 % CL upper limit for a large number of experiment in the absence
of a signal)
5 years3 years
OPERA Sensitivity
5 years data taking
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OPERA90 % CL in 5 years
OPERA: ∆m2
* assuming the observation of a number of events corresponding to those expected for the given ∆m2
(mixing constrained by SuperK)
years P3σ P4σ
3 93% 83%
5 96% 91%
Probability to observe SuperK signal
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 %
Nt / year 0.82 2.82 3.66
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ICARUS Sensitivityatmospheric beam
Sensitivity similar to OPERA!
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• Use a very intense proton beam dump to produce neutrinos = SuperBeam – Low energy (0.2-2 GeV) low ? m2
– Medium baseline (~100 km) large rate– Massive detectors (20-1000 kton) low sin22T
• Measurement program:– Improve ? m2
23, sin22T23
– Measure ?13! Totally unconstrained!– Possibility of measuring CP violating phase d!
• Sites– CERN-Modane (SPL, 130 km)– Tokaimura-Kamioka (JAERI, 295km)
SuperBeams
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SuperBeams: 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*1014 ppp / 3.3 sec
• Phase I– approved– start operation 2007
• Detector exists!
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SuperBeam Physics• CP violation (phase II)• Sensitivity (phase I)
– ?µ disappearance (1 year)
212 12
13
( ) ( )
( ) ( )
sin2sin
4 sin
eeCP
ee
P PA
P P
m LE
µµ
µµ
ν
ν ν ν ν
ν ν ν ν
θ δθ
→ − →=
→ + →
∆= ⋅ ⋅
223
2 4 223
2 313
(sin 2 ) 0.01
( ) 2 10 eV
sin 2 10
m
δ θ
δ
θ
−
−
≈
≈ ×
<
Only possible,
if KamLAND
confirms LMA!
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Mostly ruled out Mostly ruled out by most recent by most recent
SNO resultSNO result
KamLAND SensitivityMeasuring ?e disappearance!
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Neutrino Factory• Muon storage ring: The Ultimate Neutrino Source
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Neutrino Factory Physics
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Summary• Present
– K2K (nice data until 2001 and later)– KamLAND (just started taking data)
• Future– MINOS (cosmics 2001, beam 2005)– OPERA (beam 2005)– ICARUS (2005, partially approved)– JHF-SuperK (2007, not yet approved)
• Science fantasy– Neutrino Factories (2010, at the earliest)