1T.Kobayashi (KEK)

(Present long baseline neutrino experiments and)(Present long baseline neutrino experiments and)

Future Projects to measure Future Projects to measure θθ1313 and the CP and the CP violation phaseviolation phase

Takashi KobayashiIPNS, KEK

Aug. 9, 2004@Hanoi

Contents1. Introduction2. Present LBL experiments3. Future accelerator based projects4. Reactor experiments5. Summary

2T.Kobayashi (KEK)

IntroductionIntroduction• Evidences of ν oscillation

– Atm ν (SK,1998) & solar ν (SK+SNO,2001)– Finite masses!! & Large mixings!!!!!– First evidence beyond SM

• Definite confirmation w/ diff systematics– Present (1st generation) long baseline (LBL) experiments (for atm ν)– Players: K2K (1999~), MINOS (2005~), ICARUS/OPERA(2006~)

• Next steps– Understand whole structure of ν mass/mixing– How similar/different from quark sector?

• “Standard” mixing w/ 3x3 matrix?• Mass hierarchy?• CP violation?Would lead physics beyond SM

– Next generation LBL experiments and reactor exp.• w/ High statistics and small systematics

• New era of precision “Neutrino Flavor Physics”– Cf. Have been done last ~40yrs for quark sector

3T.Kobayashi (KEK)

The K2K The K2K (KEK(KEK--toto--KamiokaKamioka) ) ExperimentExperiment• The first & only running LBL ν

osc. Experiment (1999~)νµ beam (99%) with <E> ~ 1.3GeV w/ KEK 12GeV-PS

• Confirmation of atm ν resultsννµµ disappearancedisappearance and νeappearance

)27.1(sin2sin.2

22

ν

θE

Lmprob ∆⋅=

Signature (νµ else)•Reduction of # of events•Spectrum distortion

4T.Kobayashi (KEK)

Latest Latest ResultsResults on on ννµµ disapp.(Junedisapp.(June 2004)2004)

150.9Null-oscillation104.8Best Fit:108Observation:

Number of eventsPRELIMINARY

Eνrec

0

2

4

6

8

10

12

14

16

18

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Entries 56

[GeV]

even

ts/0

.2[G

eV]

Best Fit(KS prob: 52%)

No Oscillation(KS prob: 0.11%)

(normalized by area)

K2K-I & K2K-II

10-4

10-3

10-2

10-1

0 0.2 0.4 0.6 0.8 1sin2(2θ)

∆m2

[eV

2 ]

68%90%99%

• Best fit in phys. (all) region– sin22θ = 1.00 (1.53)

∆m2 [eV2] = 2.73×10−3 (2.12)

• Confirmed ν osc at 3.93.9σσ level

Eνrec spec for 1ring µ events

∆m2=1.7~3.5x10-3 eV2

@sin22θ=1 (@90%CL)

2.52.5σσ

2.92.9σσ

8.9x1019 POT (1999Jun~2004Feb)(1020POT proposed)

6.110.10

−−

5T.Kobayashi (KEK)

10-4

10-3

10-2

10-1

0 0.1 0.2 0.3 0.4 0.5

sin22θµe~0.5sin22θ13

∆m2

(eV

2 )

K2K(90%CL)

CHOOZ(90%CL)SK atm.νallowed (90%CL)

Comparison w/ other resultsComparison w/ other results

(same as prev page)

ννµµ disappearancedisappearance

PRL93(2004)051801

ννee appearanceappearance

Consistent w/ Consistent w/ SK SK atmatm νν resultresult

νe disapp

6T.Kobayashi (KEK)

MINOSMINOS

Wide band νµ beam

30205

735km

• wide band νµ beam w/ FNAL 120GeV Main Injector (0.4MW)

• (magnetized)Iron-scintillator sampling calorimeter– 5,400tons @ far, 980tons @ near

νµ CC int./MINOS/yr ~ 2,500 (LE beam)• High precision νµ disappearance• Far detector fully operational since 2003• Beam line almost completing• Start from 2005

Far detector

First Horn being Installed

7T.Kobayashi (KEK)

CCERN ERN NNeutrino to eutrino to GGranran SSassoasso (CNGS)(CNGS)

732km

E(GeV)

ν µC

C/k

T/a

n

• Wide band νµ beamw/ CERN 400GeV SPS <Eν>~17GeV

• Two experiments– OPERA: 1.7kt

Emulsion cloud chamber

– ICARUS: 3kt Liq. ArTPC

• ~5500νµ event/kt/yrντ appearance

• Under construction• First beam to GS

May 2006

8T.Kobayashi (KEK)

For ∆m2 = 0.0025 eV2, sin2 2θ = 1.0

Expected sensitivitiesExpected sensitivitiesνµ disappearance ντ appearance

MINOS 5yrs90% and 99% CL

δ(∆m2)~2x10-4eV2

δ(sin22θ)~5%read from above plot

MINOSMINOS

0.711.9ICARUS1.117.2OPERABGSig

∆m2=2.5x10-3eV2

Full mix.5yrs of runningICARUS: 1.5kt fid mass

Expected signal

9T.Kobayashi (KEK)

3 flavor mixing3 flavor mixing

ilil U νν Σ=Weak Mass eigenstates

Maki-Nakagawa-Sakata Matrix

−⋅

⋅

−⋅

−=

=

−1313

1313

2323

23231212

1212

321

321

321

0010

0

00010001

00

001

10000

cs

sc

ecssccs

sc

UUUUUUUUU

U

i

eee

δ

τττ

µµµ

sij=sinθij, cij=cosθij3 mixing angles and 1 CPV phase

sin22θ12∼0.8(SolarLBL reactor)

sin22θ23~1(Atm ν) Reactor

If neutrino have finite mass, weak and mass eigenstates can differ

Unknown 2 parameters

LBL acc. experiments

mi: 3 masses, ∆∆mmijij: 2 differences: 2 differences

10T.Kobayashi (KEK)

WhatWhat’’s next?s next?00??=|Ue3|2=sinθ13

2

00??=|Ue3|2=sinθ132

• Only unknown mixing θ13– Only upper bound from CHOOZ reactor exp– At the same ∆m2 as νµ disapp. Support 3gen. mix. framework– Open possibility to search for CPV (θany=0 No CPV)

• Mass hierarchy (sign of ∆m2)• CPV• Approaches

– LBL experiment: Multi purpose (θ13, sign(∆m2),CPV, θ23,∆m232)

– Reactor-based νe disappearance: single purpose (θ13), complementary

213

223

212 mmm ∆≈∆<<∆

11T.Kobayashi (KEK)

ννµµ ννee appearance in LBL expappearance in LBL exp

δ −δ, a -a for eννµ →

⋅

⋅×= −

]GeV[]cmg[][eV1056.7 3

25 Ea ρMatter eff.:

CP-odd

δθθ sin

sin2sin

13

12212 ⋅⋅∆≈

+−≡

ELm

PPPPACP

Solar

MainMain

MatterMatter

13CP13

2e sinθ

1A ; 2θsin)N(ν ∝∝

Size of θ13 critical !

12T.Kobayashi (KEK)

~1GeV νµ beam(×100 of K2K)

Tokai

T2K experiment T2K experiment ((approved & start in 2009approved & start in 2009))

Physics motivationsDiscovery of νµ→νe appearancePrecise meas. of disappearance νµ→νx

Discovery of CP violation (Phase2)

Kamioka

J-PARC0.75MW 50GeV PS

Super-K: 50 ktonWater Cherenkov

Phase2:4 MW ?

Phase2: MtonHyper-K?

Long baseline neutrino oscillation experiment from Tokai to Kamioka.

13T.Kobayashi (KEK)

Nuclear and ParticleExperimental Facility

Materials and Life Science

Experimental Facility

Neutrino to Kamiokande

Linac(350m)

3 GeV Synchrotron(25 Hz, 1MW)

Nuclear Transmutation

50 GeV Synchrotron(0.75 MW)

Construction2001~2008

JJapan apan PProton roton AAccelerator ccelerator RResearch esearch CComplex (Jomplex (J--PARC)PARC)

14T.Kobayashi (KEK)

February, 2004

TOKYO

KEK

JAERI

NARITA

J-PARC In JAERI Tokai-siteJAERI:Japan Atomic Energy Research Institute

60km

15T.Kobayashi (KEK)

50G

eV rin

g

target station

De

ca

y v

olu

me

(

Beam dump

( )

Near detector

Muon monitor

( )

Primary proton

beam line

target

Cryogenics

Cryogenics

Extraction point

( )

130m

280m

Primary proton beam lineTarget/Horn systemDecay volume (130m)Beam dumpMuon monitorNear neutrino detector (280m)Second near neutrino detector (~2km): not approved yet

Components

Approved in Dec. 2003Approved in Dec. 2003for 5 years constructionfor 5 years construction(2004~2008JFY)(2004~2008JFY)

Extractionpoint

Target/HornsTarget station

Muon monitor

beam dump

Near neutrino detector

Decay volume

Primary Protonbeam line

50GeVring

SK direction

JJ--PARC Neutrino facilityPARC Neutrino facility

16T.Kobayashi (KEK)

• Decay volume part• July, 2004

Ground breaking of Ground breaking of νν facility @ Jfacility @ J--PARCPARC

17T.Kobayashi (KEK)

Off Axis BeamOff Axis Beam

(ref.: BNL-E889 Proposal)

θTargetHorns Decay Pipe

Super-K.

Quasi Monochromatic Beamx 2~3 intense than NBB

First real application

Statistics at SK(OAB 2 deg,1 yr,22.5 kt)

~ 4500 νµ tot ~ 3000 νµ CC νe ~0.2% at νµ peak

Tuned at oscillation maximum

OAB2.0degOAB2.5degOAB3.0deg

On-axis

18T.Kobayashi (KEK)

0

5

10

15

20

25

30

35

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5Reconstructed Eν(GeV)

Expected Signal+BGsin22θ13=0.10sin22θ23=1.0∆m2=0.003eV2

Total BG

BG from νµ+antiνµ

T2K sensitivity on T2K sensitivity on ννee appearanceappearance

totalνeνµνeνµ

36.411.524.90.51.710.712.00.01139.5114.624.90.51.710.712.00.1

Signal + BGSignal

Background in Super-K (as of Oct 25, 2001)sin22θ13

sin22θ13

∆m2

Off axis 2 deg, 5 years

Off axis 2 deg, 5 yearsat

Sin22θ13>0.006 C

HO

OZ

excl

uded

x20

δ=0, θ23=π/4

10%10% sys. err

19T.Kobayashi (KEK)

Sensitivity for CPV in T2KSensitivity for CPV in T2K--IIIIJHF-HK CPV Sensitivity

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1sinδ

sin2 2θ

13

no BGsignal stat only

(signal+BG) stat only

stat+2%syst.stat+5%syst.

stat+10%syst.

CHOOZ excludedsin22θ13<0.12@∆m31

2~3x10-3eV2

T2K 3σ discovery

3σ CP sensitivity : |δ|>20o for sin22θ13>0.01 with 2% syst.

4MW, 540kt2yr for νµ6~7yr for νµ

δθθ

ν

sinsin

2sin4 13

12212 ⋅⋅∆≈EmACP

∆m212=6.9x10-5eV2

∆m322=2.8x10-3eV2

θ12=0.594θ23=π/4

T2K-I 90%

20T.Kobayashi (KEK)

NONOννAA• Use Existing NuMI beamline• New 50kt fine grained

detector @~800km and @ 12km off axis

• Liq scint. tracker & particle board absorber (1/3X0)(Alternative:full active liq.sci.)

• Possible future upgrade of MI (0.4MW 2MW):Proton driver

• Proposed. (2008?~)

Assuming ∆m2=2.5x10-3eV2

Messier, ν2004

21T.Kobayashi (KEK)

NONOννA Physics ReachA Physics Reach

50kton baseline detector 50kton baseline

detector

Feld

man

, Asp

en P

AC

200

4

ννee appearanceappearance Mass hierarchyMass hierarchy

22T.Kobayashi (KEK)

Europe: Europe: SPLSPL FrejusFrejusGen

eve

Italy

130km

40kt400kt

• 4MW 2.2GeV Superconducting Proton Linac (SPL) @ CERN

• Low energy wide band (Eν~0.3GeV)• L=130km• Water Cherenkov 40 400kt (UNO)• ~18,000 νµ CC/year/400kt

θ13, CPV• Small matter effect• SPL in R&D, UNO in conceptual design

23T.Kobayashi (KEK)

BNLBNL--HomestakeHomestake• 28GeV AGS upgrade to 1MW

(2MW) cf current 0.1MW• Wide band beam (0.5~6GeV)• L=2,540km• Mton detector• ~13,000 νµ CC/year/500kt• Cover higher osc. maximaGoals

νe appearance• Sign of ∆m23• CPV

θ12, ∆m12Possible w/ only ν run at certain

parameter region• LOI written.

(Ref: Diwan et al., PRD68, 012002, 2003)

2540 kmHomestake BNL

µ

0

50

100

150

200

250

0 1 2 3 4 5 6 7 8 9 10Reconstructed ν Energy (GeV)

BNL-HS 2540 km

sin22θ23 = 1.0

∆m2 32 = 2.5e-3 eV 2

1 MW, 0.5 MT, 5e7 sec

No oscillations: 13290 evts

With oscillations: 6538 evts

Background: 1211 evts

24T.Kobayashi (KEK)

Brookhaven to Brookhaven to HomestakeHomestake Physics ReachPhysics Reach

Even with only ν data, CP violation and mass hierarchy are visible

in some regions of parameter space.

Normal hierarchy Reversed hierarchy

But with both ν and ν running, CP precision much higher

Diwan, 3/2004 APS study meeting

25T.Kobayashi (KEK)

G. Mention (APC)

Near detector Far detector

Neutrino Detection Rate per Power Generation

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 1 2 3 4 5 6 7 8 9 10Energy (MeV)

P.Vogel, PRD, Vol29, 1918 (1984)

P. Vogel et al. PR. C Vol.24, 1543 (1981)

H.V.Klapdor et al., PL 122B 22(1982)H.V.Klapdor et al., PRL vol48, 127 (1982)

G.Zacek et al., PRD 34 (1986) 2621

235U 238U

241Pu

239Pu

3 4 Eν (MeV)

Reactor Reactor ννee disappearancedisappearancen νe from nuclear reactor <E>~3MeVn 1-P(νe→ νe) = sin2(2θ13)sin2(∆m2

31L/4E) + O(∆m221/∆m2

31) : pure θ13

n Small systematic error (<1%) requiredn Identical near det @ O(100)m & far det @a few km

8MeV

30μs

1~8MeV

t

Signal Property

ν e + p → n + e +

e + + e − → 2 γE ν − 0 .8 MeV( )

n + Gd → Gd ' + γ s E∑ = 8 MeV( )

νe signature

26T.Kobayashi (KEK)

ComplementarityComplementarity of Reactorof Reactor--Accelerator Meas.Accelerator Meas.

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14

sin2 2θ13

P ν µ → νe( )

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14

Reactor Measurement= Pure sin22θ13 measurement

Reactor Measurement

J-PARCMeasurement

sin2 θ23 =0.610.39

Reactor-Accelerator combination => a lot of physics potential

* If accuracyis good enough=> |sinδl |

* Answer to θ23 degeneracy

27T.Kobayashi (KEK)

Reactor experiment proposalsReactor experiment proposals

Diablo Canyon

Braidwood

Angra

PenlyChoozCruas

Krasnoyarsk

Taiwan

Kashiwasaki

Daya bay

0.02~0.03

90%CL Sensitivity90%CL Sensitivitysinsin22θθ1313 θθ1313(deg)(deg)

2008

Approved in Approved in francefrance

28T.Kobayashi (KEK)

Near detector site (to be built)

Existing Far detector site

DoubleDouble--CHOOZCHOOZ• Twin reactor cores

– P=2x4.2 GWth• Two 10 tons detectors

– 80% dodecane + 20% PXE + 0.1% Gd

– Near: 100-200 m – 60-80 mwe– Far: 1.05 km - 300 mwe

• 3 years Sensitivity–– 0.6%0.6% systematics– No signal: sin2(2θ13) < 0.02-03

(90% C.L.)– Signal: sin2(2θ13) > 0.04-05 (3σ)

• Prospect (approved & funded approved & funded in Francein France)– 2007: far detector running – 2008: near detector running– Cost ~7Meuros + civil constr.

Near

Far

29T.Kobayashi (KEK)

SummarySummary• First 1st generation experiment K2K

– Confirmed ν oscillation observed in atm ν at SK @3.9σ– Waiting precise meas. from MINOS(2005~), ντ app. from CNGS(2006~)

• Next important issues– Discovery and measurement of only unknown mixing θ13– Mass hierarchy– CP violation

• Next generation LBL experiments covers most– T2K using J-PARC and SK started construction. Start exp. In 2009

θ13 sensitivity ~0.006 (90%CL), ~0.018 (3σ)• |δ|~20deg in phase 2

– NOνA proposal w/ similar potential to T2K• Pure θ13 measurements by reactor experiments

– complementary to disentangle parameter relationsθ13 sensitivity 0.01~0.03 (90%)

– Systematic error (<1%) is key issue– Double-CHOOZ is partially approved

• Neutrino field will continue to be very exciting for coming decades