K2K, T2K
および将来のニュートリノ実験
T. Nakadaira(KEK)For T2K collaboration

Neutrino 2006 Talks on Oscillation exp.
zK2K (1999 - 2005)“K2K Cross Section Measurements”, R. GranzT2K (2009 - )“T2K and beyond”, T. NakadairazCNGS (2006 - )“CNGS”, C. Sirignano

zNoνa (2010/2011? - )“Future Experiments (NOVA)”, P. Shanahan

zOther future experiments“Superbeams (physics and expts)”, B. Marciano“Neutrino Factories & Beta Beams”, L. Camillieri

zc.f.
“Secondary Production (HARP, MIPP, E910)”, G. Mills2

K2K & T2K LBL ν experiment

Under Construction

Completed Experiment

750kW

Near Detector

Pure νμ beam
280m
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z νμ disappearance (hep-ex/0606032)

zÆ “K2Kにおける電子ニュートリノ出現の探索”, 山本真平

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T2K and beyond
T. Nakadaira(KEK)For T2K collaboration

Physics @ T2K PHASE-Izν mixing matrix: θ13<< θ12, θ230⎛ν e ⎞ ⎛ 1⎟⎜⎜Flavor
ν = 0 cos θ 23eigenstate ⎜⎜ μ ⎟⎟ ⎜⎜⎝ν τ ⎠ ⎝ 0 − sin θ 230 sin θ13e −iδ ⎞ ⎛ cos θ12⎟ ⎜10⎟ ⎜ − sin θ120cos θ13 ⎟⎠ ⎜⎝ 00 ⎞ ⎛ cos θ13⎟ ⎜sin θ 23 ⎟ ⎜0cos θ 23 ⎟⎠ ⎜⎝ − sin θ13e −iδ

SK Atm., K2K, MINOS
θ23 ~ 45°Δm223 ~ 2.5 × 10-3 [eV2]θ13,δ are still unknown.

zT2K-I searches for νμÆ νe.

(P(ν μ → ν e ) ≈ sin 2θ13 sin θ 23 sin Δm 31 L 4 E
2(2)

2(2)

00 ⎞ ⎛ν 1 ⎞⎟ ⎜ ⎟Mass0 ⎟ ⎜ν 2 ⎟eigenstate
1 ⎟⎠ ⎜⎝ν 3 ⎟⎠Solar, KamLAND
θ12 ~ 34°Δm212 ~ 8×10-5 [eV2])

m 4 J r sin δ Δm 2 21 L 2 E sin 2 Δm 2 31 L 4 E + ...
− for ν+ for νsin θ12cos θ12

Excluded area
sin22θ23=0.93
sin22θ23=1(Approximation @ Δm231L/4E ~ π/2, Δm232~Δm231)

J r ≡ cos θ 12 sin θ 12 cos θ 23 sin θ 23 cos 2 θ 13 sin θ 13zSize of CP asymmetry depends on θ13 !!
Matter effect is small in (Eν , L) in T2K.

 Δm213=Δm223−Δm212 ~ 2.5×10-3 [eV2]Æ sin22θ13 < 0.15

22

Principle of T2K … Quite similar to K2K
ΦνND

Extrapolation

measurementΦνSK(expected)

ComparisonÆ ν oscillation
parametersSKSKNν , Eνz Δm2 = ~2.5x10-3[eV2], L=295km
Æ1st Oscillation max. @ Εν ~ 0.6 GeV
zUse Sub-GeV νμ beam

CC-QE is dominant process in ν-N interactions.
Neutrino Energy reconstruction by CC-QE kinematics … δE/E ~ 10%μ, eνθlneutronproton

mN El − ml 2Eν =mN − El + pl cos θ l2

Fraction of high energy ν (Eν ∼ a few GeV) is required to be small.
• CC-non QE events are background for Eν reconstruction.
• π0 from NC events are dominant background for νe signal.
μ, eν
ν
νπ,…
neutronn, pprotonπ0γÆe

23Japan Proton Accelerator Research Complex()Multipurpose Proton Accelerator

Feb. 2006

z400MeV LINAC (200MeV@T=0)Æ 1MW 3GeV RCS
Æ 0.75MW 50GeV MR (30GeV @ T=0)
1×1021 protons/year (130days) [in 50GeV operation.]c.f. K2K: ~1×1020 POT(6 years including 1 year interruption)
Joint project by JAEA (former JAERI) and KEK
24

J-PARC ν-beam line
zConventional νμ beam: protons + Graphite target → pions π+ or π− is focused selectively
by 3 electromagnetic horns.
π+ → μ+ + νμ or π− → μ− + νμzPseudo-Monochromatic beam
by Off-Axis method: (OA = 2° ~ 2.5°)

Extraction point

Set peak of ( flux × σCC ) @ oscillation max.
Fraction of high energy neutrino is small.

Target &horn

Oscillation Prob.
@ L=295km
Δm2=2.5×10-3,3.0×10-3[eV2]

Decay Volume

ν energy spectrum (flux × Cross Section)

Beam dump
μ-monitor

OA0°OA2°
OA2.5°
OA3°

280m OAν Near Detector
SK25

Accelerator construction status
Middle ofLinac Tunnel

3 GeV
Extraction Point
50 GeV Tunnel
MR Æ Neutrino beam line

ν beam-line
Decay Volume

From 50 GeV toNeutrino Area

Problem in RF system for MR:
Some of the RF cores discharges with 15kV/gap in long term tests.
Å The failure components have already been identified.
* The MR commissioning will start with current RF system on schedule in low power.
* The parallel R&D work is in progress aiming to replacing RF system around 2010.26ν beam-line Construction is going well !
zSuperconducting combined function
magnet for Proton beam line.
First module of production version
Cool down test (4.6 K)
Excited to 7728A (50GeV operation+5%margin.) w/o quench.

zMechanical Prototype ofGraphite Target
Enough thermal shock resistanceagainst 0.75MW beam.
He-gas cooling system isconstructed.

zPrototype of 1st Horn
 Test operation with 250kA current
So far, There is no problem up with this test.

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J-PARC schedule & Beam Power estimation

0.75 MW

Hardware upgrade isnecessary for ≥ 1MW.

Target date for new RF system installation.

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ν Near Detector @ 280m
zOn-axis detector
Measure ν-beam profileÆ ν-beam direction at 1mrad precision.
 iron - scintillator stacks × 14 units(2unit)

[e3.
~0t
ts/nveoilpsn/l]zOff-axis detector: In Magnet (B=0.2T)
Measure ν-flux in SK direction : ΦνND(Eν).
• Measure νμ, νμ and νe+νe fluxes separately.
• Neutrino Energy Å CC-QE kinematics.

Cross sections of ν interactions• CC-1π/CC-QE … BG for Eν reconstruction• NC-π0 production … BG for νe detection

SMRD

Reuse of UA1 magnet 29

Far Detector: SK-III
z50kt Water Cherenkov detector
Ready for T2K !!!
zSK reconstruction is completed in Apr. 2006.
Æ Back to 40% Photo coverage. Start full operation in July, 2006

©ICRR, Univ. of Tokyo30

Prospects in T2K Phase-Izνe appearance

T2K 90%CL sensitivity
sin22θ23 = 1.0 is assumed.
5×1021 POT ~ 5 years@ full intensity(OA2.5°)0.008 @ Δm213=2.5×10-3[ev2], δ=0

sin22θ13 = 0.1# of eventsin 0.35~0.85 [GeV]
Signal… 103
Beam νe BG … 13
BG from νμ … 105×1021 POT MC
Stat. error+ Syst. error for BG subtraction (10%)

31Prospects for T2K Phase-I (Cont’d)z νμ disappearance : P( νμ Æ νμ)=1-sin2θ23sin2(1.27 Δm223L/E)
Goal : δ(sin22θ23)~0.01, δ(Δm223) <1×10-4 [eV2]

6K2K & SK

50(OA2.5°)
MC

2.9
2.8

2.6

31T2K 5×1021 POT (Stat. only)~ 5years @ full Intensity

2.742Δm2 [10-3 eV2]Δm2 [10-3 eV2]

Statistics ×502.5

K2K 68%
K2K 90%K2K 99%SK L/E 90%

0.20.4
K2K … hep-ex/0606032
SK… Phys. Rev. Lett. 93,101801(2004)

0.6

10.8
sin2(2θ)--68%CL--90%CL--99%CL32

Intermediate detector @ 2kmpπTarget0m

2.5º

Far Detector(SK)

Near Detector

280m

2 kmzEν spectrum @ 2km~ Eν spectrum @ SK w/ooscillation
Æ Uncertainties from Far/Nearratio is smaller than ND@280m.
zPossible Detector configuration
Liquid Ar TPC
Water Cherenkov• Same target & ν reconstruction
algorithm as SKMuon Range Detector

νDtioceri

295 kmnFacilities for 2km is to be requested in Japanafter the commissioning of J-PARC facilities.
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Beyond T2K-I

Possible upgrade: T2K Phase-IIzIf sin22θ13 measured @ T2K-I > 0.01, it paves the way for ν CP-violation
search.
 J-PARC upgrade: 0.75MW Æ 4MW
 SK (50kt) Æ Hyper Kamiokande (HK): ~1Mt

Assumptions:Δm212=6.9x10-5eV2
Δm322=2.8x10-3eV2
θ12=0.594,θ23=π/4• Proton decay search: test of GUT.

z Comparison between νμ and Anti-νμ beam.
P(ν μ → ν e ) − P (ν μ → ν e )Δm12 L sin 2θ12
ACP =≈⋅⋅ sin δP (ν μ → ν e ) + P (ν μ → ν e )Esin θ132sin 2θ13

T2K Phase-I
Sin22θ13 3σ sensitive region

23σ sensitivity (4MW,540kt)
ν-run=2 year, ν-run=6~7year
CHOOZ excluded
sin22θ13<0.12@Δm312~3x10-3eV2

0.14
0.12

no BG, signal stat only
0.1

(signal+BG) stat only
stat+2%syst.
stat+5%syst.
stat+10%syst.

0.08
0.06
0.04
0.02000.1

0.2

0.3

0.4

0.5

0.6 0.7

0.8

0.9 1 35sinδ

T2KK … Another far detector @ Korea
FD @~ 1000km

Distance from the target (km)SKÆ HK

JPARC

M. Ishitsuka et. Al
Hep-ph/0504026

Off-axis angle

z Far detector identical with (SK)/HK @ 2nd Oscillation Maximum point.
Contribution of CP asymmetric term: ×3 compared to SK position.
Matter effect become significant. Æ Possibility to resolve mass hierarchy()(If δ is suitable,it may possible
to distinguish.

)“Inverted”

sin22θ13=0.05
δ … 0~2π“normal”

CPV term ≈ m4 J r sin δ Δm 2 21 L 2 E sin 2 Δm 2 31 L 4 E36

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Far Detector: 25kT [15.7×15.7 × 110 m3](18.25kT Liquid Scintillator in PVC cells+WLS+APD)
Near Detector:
Liquid Scintillator + Muon Catcher (OA 4 – 21 mrad)39

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6×1021POT: 6year, 25kT, 1MW beam41

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The CNGS project
andOPERA experiment at LNGS

Chiara Sirignano (Salerno University)
for the OPERA Collaboration

Neutrino 2006

Santa Fe, June 13-19 432006

Oscillation Projectwith Emulsion tRacking Apparatus
International Collaboration (Europe + Japan)
IIHE (ULB-VUB), Brussels
Sofia
IHEP Beijing, Shandong
IRB Zagreb
LAPP Annecy, IPNL Lyon, LAL Orsay,
IRES Strasbourg
Berlin Humboldt, Hagen, Hamburg, Münster, Rostock
Technion Haifa
Bari, Bologna, LNF Frascati, L’Aquila, LNGS, Napoli,Padova, Roma La Sapienza, Salerno
Aichi, Kobe, Nagoya, Toho, Utsunomiya
INR Moscow, ITEP Moscow, JINR Dubna, Obninsk
Bern, Neuchâtel, Zurich
METU Ankara• Long baseline experiment• CNGS pure νμ beam, <L> = 732 km, <E> = 17 GeV• Appearance signal νμ → ντ (by product νμ → νe )• Hybrid setup (Nuclear Emulsions + electronics)• Atmospheric neutrino data allowed region oscillation search44νμ → ντ oscillation searchτ decaychannelSignal
Δm2= 2.4 x 10-3 eV2

Δm2

Background= 3.0 x 10-3 eV2

τ→µ3.6

5.60.23

τ→e

4.3

6.7

0.23

τ→h

3.8

5.9

0.32

τ → 3h

1.1

1.7

0.22

ALL

12.8

19.9

1.0

full mixing, 5 years run @ 4.5x1019 pot / year

Main background sources:-charm production and decays- hadron re-interactions in lead- large-angle muon scattering in lead45

700 m

100 m

1000m

67 m

vacuumDecay tube
vacuum tests successful

HornCivil engineering completed (June ’03)
Hadron stopper and decay tube installed (June ’04)
Target section completed (commissioning July ‘06)

Hadron stop46

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Detector construction status
XPCA1&2Mar ‘05

HPTA 1-･6

Mar’05-May’06

Magnet 1&2
May’03-Apr’05

Electronics
Jul’05-Jun’06

Mechanical structure
May’04-Jul’05

BMS rs & cs
Dec’05-Mar’06
VetoJun 06
SM1 Target
Dec’05-Nov’05

SM2 TargetJan-May ’06

XPCB1&2

Completed

HPTB 1-6
Jun-Dec
06
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OPERA magnet assembly
June 2006

coil

Antiseismic structure
Base magnet 249

Magnet Assembly in Hall C September 2003