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The T2K Neutrino Oscillation Experiment
Nick Hastings
Workshop on Next generation Nucleon decay and Neutrino detectors
2007
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
-
Outline
Introduction
The Current Situation
T2K Physics Goals
T2K Experiment Overview
Tokai Site
Neutrino Beam
Components
Analysis
T2K Physics Prospects
νµ disappearance: θ23 and ∆m223
νe appearance: θ13
Summary
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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Introduction The Current Situation
Neutrino oscillations observed• Neutrino disappearance - oscillations confirmed• Neutrinos have non-zero mass
Atmo’s & Long-baseline
νµ disappearance
|∆m223| = (2.2–2.6)× 10−3 eV2
sin2
2θ23 > 0.9
0.4 0.5 0.6 0.7 0.8 0.9 10
0.001
0.002
0.003
0.004
0.005
0.006
)23θ(22sin
)4
/c2| (
eV322
m∆|
MINOS Best Fit MINOS 68% C.L.MINOS 90% C.L.
SuperK 90% C.L.SuperK (L/E) 90% C.L.K2K 90% C.L.
MINOS Preliminary
KamLAND & Solarνe disappearance
θ 2tan
0.2 0.3 0.4 0.5 0.6 0.7 0.8
)2
(eV
2m
∆KamLAND+Solar fluxes
95% C.L.
99% C.L.
99.73% C.L.
global best fit-5
10×4
-510×6
-510×8
-410×1
-410×1.2
∆m212 = 8× 10−5 eV2
sin2
2θ12 = 0.86
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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Introduction The Current Situation
The Parameters
Flavourνeνµντ
=1 0 00 c23 s23
0 −s23 c23
︸ ︷︷ ︸Atmo’s & Long BL
Unknown︷ ︸︸ ︷ c13 0 s13e−iδ0 1 0−s13eiδ 0 c13
c12 s12 0−s12 c12 00 0 1
︸ ︷︷ ︸KamLAND & Solar
Massν1ν2ν3
where sij ≡ sin θij , cij ≡ cos θij• Is sin2 2θ23 maximal?• θ13 known to be small• Reactor ν̄e disappearance experiments sin
22θ13 < 0.19
• No information on δ
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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Introduction T2K Physics Goals
T2K goals
Initial Goals
• Refine νµ disappearance:
P(νµ → νµ) ' 1− cos4 θ13 sin2 2θ23 sin2 Φ23≡ 1− sin2 2θµτ sin2 Φ23
• Measure νe appearance:
P(νµ → νe) ' sin2 θ23 sin2 2θ13 sin2 Φ23≡ sin2 2θµe sin2 Φ23
Where:
Φij ≡∆m2ij L
4E
=1.27(∆m2ij/eV
2)(L/km)
E/GeV
Future Goals
• Refine νe appearance• IF νµ → νe is sufficiently large:
• look for CPV with ν̄µ beam
ACP =P(νµ → νe)− P(ν̄µ → ν̄e)P(νµ → νe) + P(ν̄µ → ν̄e)
=∆m212
4E
sin 2θ12sin θ13
sin δ
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
-
T2K Experiment Overview
T2K
• Next generation long-baseline neutrino oscillation experiment• Initial Phase - (0.75 MW- Super–K) ∼ K2K ×100• Possible Secondary Phase: CPV - (4 MW- Hyper–K)∼ Initial Phase ×100
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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T2K Experiment Overview Tokai Site
Tokai site
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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T2K Experiment Overview Neutrino Beam
Off-Axis Neutrino Beam
Target & HornsSuper-K
Near DetectorsDecay Volume νµπ
p
π(mπ,pπ)
µ(mµ,pµ)
ν(Eν)θOA
Eν =m2π −m2µ
2(Eπ − pπ cos θOA)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 1 2 3 4 5 6 7 8 9 10
θOA = 0.0°
θOA = 2.0°
θOA = 2.5°
θOA = 3.0°
pπ (GeV/c)
Eν
(GeV
)
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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1.4.ニュートリノ実験施設の概要
15
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図1.6:
ニュートリノ実験施設の概要
T2K Experiment Overview Neutrino Beam
Beamline
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
-
1.4.ニュートリノ実験施設の概要
15
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図1.6:
ニュートリノ実験施設の概要
T2K Experiment Overview Neutrino Beam
Proton Beamline
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
SC Magnet doublet
• 3.3× 1014 Protons/pulse• 0.75 MW• 30 GeV• Bunch structure:
4.2 us
58 ns 598 ns
• Repetition rate: 3.64 s• Superconducting magnets
in bending section
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図1.6:
ニュートリノ実験施設の概要
T2K Experiment Overview Components
Proton Beamline - Monitors
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
Intensity (CT)
• 4 monitors
Position Monitor
(ESM)
• 20 monitors• Better than
1 mm resolution
Profile Monitor
(SSEM)
• 19 monitors• Insert for beam
tuning
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15
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図1.6:
ニュートリノ実験施設の概要
T2K Experiment Overview Components
Target Station
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
• He vessel (reduce NOx &Tritium creation)
• Highly radio active (10 Sv/h)• Remote handling required for
maintenance
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1.4.ニュートリノ実験施設の概要
15
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図1.6:
ニュートリノ実験施設の概要
T2K Experiment Overview Components
Target Station
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
• Under construction
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1.4.ニュートリノ実験施設の概要
15
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図1.6:
ニュートリノ実験施設の概要
T2K Experiment Overview Components
Horns
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
• Three horns• Prototypes made for each type• Tested to 320 kA• Target located in 1st horn
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1.4.ニュートリノ実験施設の概要
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図1.6:
ニュートリノ実験施設の概要
T2K Experiment Overview Components
Target
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
• Isotropic Graphite (IG-430)• Encapsulated in Titanium alloy
tube
• L = 90 cm, φ=26 mm• Energy Deposit: 20 kW
• Helium cooled• ∆Tpulse = 200 ◦C
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1.4.ニュートリノ実験施設の概要
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図1.6:
ニュートリノ実験施設の概要
T2K Experiment Overview Components
Decay Volume
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
• 94 m• Helium filled• Water cooled
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1.4.ニュートリノ実験施設の概要
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図1.6:
ニュートリノ実験施設の概要
T2K Experiment Overview Components
Beamdump & Muon Monitors
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
Beamdump
• Beamdump• Graphite blocks• ∼ 3 m× 3 m× 5 m• Al pipes for water cooling• tmax ' 500 ◦C(Graphite),
90 ◦C(Al) @ 3 MW
• Muon Monitors• planes of semiconductors and
ionisation chambers
• placed behind beam dump• profile centre precision: 3 cm
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1.4.ニュートリノ実験施設の概要
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図1.6:
ニュートリノ実験施設の概要
T2K Experiment Overview Components
Near Detectors at 280 m
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
INGRID (On-Axis)
• Iron-scintillator stacks• 10 m× 10 m coverage• Monitor νµ beam
• Profile• Direction
• σθ = 0.18 mrad• Shift resolution corresponds to
1 mm at target
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図1.6:
ニュートリノ実験施設の概要
T2K Experiment Overview Components
Near Detectors at 280 m
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
ND280 (Off-Axis)
• Meas. ν-flux in direction of SK• Both νµ and νe• Tracker for CC-QE kinem. (Eν )
• Cross sections of ν interaction• CC-nQE vs CC-QE: for Eν
recon.
• NC-π0 production (fake νe)
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T2K Experiment Overview Components
Far Detector - Super-Kamiokande
• φ× h = 39 m× 41 m• 11146(inner)+1885(outer) PMTs• Fiducial volume 22.5 kt
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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T2K Experiment Overview Analysis
Eν Reconstruction
P(νµ → νµ) = 1− sin2 2θµτ sin2(
1.27∆m2L
Eν
)Signal
θνµ + n→ µ+ p
p
µ−
νµ
(Eµ,pµ)Charged Current Quasi-Elastic (CC-QE)
E recν =mnEµ −m2µ/2
mn − Eµ + pµ cos θ
Fit cone to PMT hits to
reconstruct Eν :
• Utilise energy and timinginfo. from PMTs
For a 1 GeV µ achieve
• σ(Eν/Eν) ' 3%• Flight direction 3%• Vertex position 30 cm
νµ CC cross sections
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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T2K Experiment Overview Analysis
Backgrounds
CC-nQEµ−
νµp
πs
νµ + n→ µ+ p+πsθ
(Eµ,pµ)
• Incorrect E recν determination
Neutral Current (NC)
νµ
νµp
νµ + n→ νµ + p+πθ
π
• π0 can look like electron• Hampers νµ → νe search
• Intrinsic νe content in beam• Muon/Electron separation
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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T2K Experiment Overview Analysis
Extracting Results• νe appear.: Excess of # e− over expected bkgd• νµ disappear.: Deficit # µ− & dist. of Eν .
Event rate prediction:NND =φNDσND
NSK =φSKσSK Posc
• σSK ,ND studied with ND
• Treat Fluxes as ratio: RN/F =φSKφND
• Need to understand hadron production...
Compare: NobsSK to Npred
SK= NobsND RN/F
σSKσND
0
0.5
1
1.5
2
2.5
3
3.5
0
0.5
1
1.5
2
2.5
3
3.5
ν µ Φ
(10
6/c
m2/y
r)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 1 2 3 4 5
Eν (GeV)
(ΦS
KxL
SK
2)/
(ΦF
DxL
FD
2)
(b)
SHINE (NA49 upgraded to NA61)
• π±, K± & K 0 prod.• Protons on Carbon target• 30 GeV beam approved (seek 40 & 50 GeV)• Matched to T2K conditions• Understand hadron production: Use for RN/F
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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T2K Physics Prospects νµ disappearance: θ23 and ∆m223
νµ disappearance: θ23 and ∆m223
• 5 years (1021 POT/year)
Achieved sensitivity
δ(sin2 2θ23) ' 0.01δ(∆m223) < 10
−4 eV2
Systematic error req’mentsSource Size
Non-QE/QE Ratio < 5%Energy Scale < 2%Flux Normalisation < 10%Flux Width < 10%Flux Shape < 20%
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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T2K Physics Prospects νe appearance: θ13
νe appearance: θ13• 5 years (1021 POT/year)• Error on background estimation at 10%
10-4
10-3
10-2
10-1
10-3
10-2
10-1
1sin22θ13
Δm2 1
3 (e
V2 )
θ23 = π/4(sin22θ23 = 1.0)θ23 = 0.625(sin22θ23 = 0.9)θ23 = 0.946(sin22θ23 = 0.9)
Δm212 = 8.2x10-5 eV2
tan2θ12 = 0.4
-150
-100
-50
0
50
100
150
10-3
10-2
10-1
1sin22θ13
CP
ph
ase
δ (d
egre
es)
θ23 = π/4(sin22θ23 = 1.0)θ23 = 0.625(sin22θ23 = 0.9)θ23 = 0.946(sin22θ23 = 0.9)
Δm213 = 2.5x10-3 eV2
Δm212 = 8.2x10-5 eV2
tan2θ12 = 0.4
sin2
2θ13 < 0.008 (90% C.L.)for: δ = 0, ∆m213 = 2.5× 10−3 eV2, sin
22θ23 = 1
• Factor 10 improvement on CHOOZ limits (for any δ)Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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Summary
Summary
• New accelerator facility: Large number of protons on target• Off-axis beam: Narrow Eν distribution tuned to oscillation maximum• Extensive suite of beam monitors/near detectors• Well established far detector• Physics Prospects
• Search for νe appearance: order magnitude improvement on sin2 2θ13• Precision measurements: δ(sin2 2θ23) ' 0.01, δ(∆m223) < 10−4 eV2
• T2K facility at J-PARC well underway• Start Neutrino beam commissioning April 2009
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
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Backup
Commissioning Plan
T2KK07: 3rd International Workshop on a Far Detector in Korea fT2KK07: 3rd International Workshop on a Far Detector in Korea for the Jor the J--PARC Neutrino Beam PARC Neutrino Beam ·· Sep 30,Sep 30,‘‘07 07 ·· Tokyo JapanTokyo Japan 77
Neutrino Facility Neutrino Facility at Jat J--PARCPARC
T.IshidaT.Ishida(IPNS, KEK)(IPNS, KEK)Commissioning PlanCommissioning Plan
30GeV30GeV6 bunches / h = 9 6 bunches / h = 9 (kicker rise time problem)(kicker rise time problem)Rep. period: 3.04s for Rep. period: 3.04s for FxFx (3.64s for (3.64s for SxSx))
DRY RUNDRY RUN
Install Fast Extraction
Devices
[CONSTRUCTIONCONSTRUCTION] [INSTALATION][INSTALATION] [COMMISSIONING][COMMISSIONING]
STAGE-1:Establish
Closed Orbit
PPS Rad. Protection
Install Slow Extraction
Devices
STAGE-2:Acceleration
(30GeV)
STAGE-3:Fast
Extraction
☼☼☼☼
☼☼
0.17s1.9 s
0.1s (0.7s for Sx)
0.87s
[Day[Day--one Operation Parameters]one Operation Parameters]
Asking FxHigh Intensity
Run
Nick Hastings University of Tokyo
The T2K Neutrino Oscillation Experiment
IntroductionThe Current SituationT2K Physics Goals
T2K Experiment OverviewTokai SiteNeutrino BeamComponentsAnalysis
T2K Physics Prospects disappearance: 23 and m223e appearance: 13
SummaryBackup