1

Future Prospect of Accelerator-based Neutrino Oscillation Experiments

and other next generation experiments

Two of the essential gradients of lepto-genesis

• CP violation

• B-L) 0 Majorana

2

3 ‘slits’ interferometer- possibility of CP violation in →e

e

E4

L)mm(sin)UUUU

11

222*

11e2*

2e

E4

L)mm(sinUUUU

11

232*

11e3*

3e

e

e

production detection

E4

L)mm(sin)UUUU

12

232*

22e3*

3e

Comparable amplitudesanti-?

m2~3 x 10-

solar,Kamlandm2~8 x 10-5

3 ‘slits’

Interferences

Interference

3

Importance of →e AppearanceCP Violation in Lepton Sector

in 3 generations scheme

e disappearance 1- Pee : UiReale at m2 ~ 3 x 10-3 eV2 　： interference of two m2’s

→( small Ue3 small m122 ) Two comparable terms → CPV

E

LmmUUUU

E

LmmUUUUP

ij

ijjjii

ijjji

iji

2

)(sin)Im(2

4

)(sin)Re(4

22**

222**

CPV sin12 sin23 sin13 m212 (L/E) sin

Solar and Atmospheric Solar LMA solution→ (large 12, relatively large m2

12) Near max. mixing in atmospheric (23~/4)

4

Searches for non-zero Searches for non-zero 1313

13 with reactor experiments

• <E> ~ a few MeV Disappearance

• P(ee) = 1- sin2213 ・ sin2(1.27m231L/E) + O(m2

21/m231)

Almost purepure measurement of 1313 with negligible matter effect.

13 with accelerator experiments

• <E> ~ O(GeV) appearance experiments

• P(e) = 1- sin223 ・ sin2213 ・ sin2(1.27m231L/E) + many terms

Appearance measurement of 13.

P(e) also depends on and mass hierarchy.

5

Current Proposals on Reactor Experiments

• Acc LBL exp. and Reactor 13 exp. are complementary.– Appearance signal versus Disappearance signal.– Statistics Limited versus Systematic Limited– Large CPV effect versus Pure 13 effect.– Similar Time scale (~2010)

2006

Angra

Double Chooz

Daya bayReno

1st generation: sin2(213)~0.02-0.03

2nd generation: sin2(213)~0.01

Reactor 13 exp. (2007) approved

6

3-flavor Oscillation (simplified)

ELmP e /27.1sin2sinsin 213

213

223

2

ELmP x /27.1sin2sincos1 223

223

213

4

Oscillation Probabilities when 213

223

212 mmm

e appearance

disappearance

common

m1

m2

m3

7

31322

132

232

132

13

212

13231223122

132

232

122

232

122

132

12

21313223131223122

13

21313223131223122313122

13

3122

232

132

13

sincos4

)21(8

sin)cos2(4

sinsinsinsin8

sinsincos)cos(8

sin4)(

E

aLSSSC

SSSCCSSSCCCS

SSSCCC

SSSCCSSSC

SSCP e

seigenvalue mass: ,

energy, neutrino: length,flight :

,4/

222

2

ijiij

ijij

mmmm

EL

ELm

Sij=sinij, Cij=cosij

e appearance probability at L/E ~ 103 (km/GeV)

LE

L

GeV

E

cmgE

aL

2~

4][]/[6.7

4 3

CP conserving

CP

solar

matter effect

-, a -a for e

13

Small numbers• S13

• sinΦ21 ~ 0.03

mass hierarchy

8

• L/E~3 x 102 (km/GeV)• Three contributions

1 　 Term which is same for neutrinos and anti-neutrinos2 　 CP violating term (constant in E) 　3 　 Matter effect ( proportional to L or E at constant L/E)

• It is almost impossible to change distance or neutrino energyTo get 2+3 1. Compare Neutrinos and Anti-neutrinos2. Compare with reactor data

CPV Make matter effect small (where 2 >3) Low energy and relatively short distance

Mass hierarchy Compare with higher energy measurements 3

→ e Appearance Measurements

9

e oscillation probability in sub-GeV neutrinos

sin2213=0.01

matter

total13CPCPsolar

Depends on manyparameters

10

Accelerator NeutrinosNear future

T2K

Nova

11

T2K Collaboration

• 12 Countries– Canada, France, Germany, Italy, Japan– Korea, Poland, Russia, Spain,– Switzerland, UK, USA 60 Institutes, 300 Ph.D. members

Still growing

Proposed in 2000, budget approved in 2004

12

Non-zero mass of neutrinos !Flavor Physics esp. history of neutrino studies show full of surprisesfull of surprises ( Kamiokande for Kamioka Nucleon decay Experiment ! )

• Emphasis lepton ID and the determination of E

• Eand Detector technology1. Look for un-expected in precision measurements of oscillationparameters • 3 generation frame-work (paradigm) ?

• Consistency of m2 in disappearance and appearance processes• Sub-process of flavor changing process ( in addition to oscillation)?

• Oscillation pattern2. e appearance• The last mixing to be found

• 　 23~45o 12~34o, test to 3o

• Determine future direction of neutrino experiment • Lead to only one practically possible test of CPV in leptons • Complex phase in mixing in light neutrinos → leptogenesis?

13

Main features of T2KThe distance (295km) and m2 (~2.5x10-3 eV2 )1. Oscillation max. at sub-GeV neutrino energy

– sub-GeV means QE dominant• Event-by event Ereconstruction

– Small high energy tail • small BKG in e search and Ereconstruction

2. Proper coverage of near detector(s) – Cross section ambiguity

3. Analysis of water Cherenkov detector data has accumulated almost twenty years of experience

– K2K has demonstrated BG rejection in e search– Realistic systematic errors and how to improve

4. Accumulation of technologies on high power beam

14

Beam energy QE is the best known process

1 10 E

15

TargetHornsDecay Pipe

Super-K.

decay Kinematics

OA3°

OA0°OA2°

OA2.5°

Statistics at SK (OAB 2.5 deg, 1 yr, 22.5 kt)

~ 2200 tot ~ 1600 CC e ~0.4% at peak

Quasi Monochromatic BeamTuned at oscillation maximumFar/near ‘simpler’ to evaluate

Narrow intense beam: Off-axis beam振動確率＠m2=3x10-3eV2

f

lux

0°

2°

2.5°3°

E (

GeV

)

1

00 2 8

p (GeV/c)5

Anti-neutrinos by reversing Horn current

16

+ n → + p

-

p

(E, p)

cospEm

2mEmE

N

2Nrec

E MeV E/E ~ 10%

Quasi-Elastic process

- + n → + p +

p

(E, p)

’s

+ n → + p + ’s

p’s

CC 1

NC 1

QE

inelastic

E(reconstructed) – E(true)

17

PID in SK

e-like -like

e

18

19

20

e appearance :

sin2213

Estimated background in Super-K Signal

(~40% eff.)Signal +

BG

NC

e

beam e total

0.1 12.0 10.7 1.7 0.5 24.9 114.6 139.5

0.01 12.0 10.7 1.7 0.5 24.9 11.5 36.4

sin2213

m2

Off axis 2 deg, 5 years

Off axis 2 deg, 5 yearsat

sin2213>0.006 C

HO

OZ

exc

lud

ed

21

Sensitivity to 13 as a fuction of CP-phase

KASKA 90%(NuFact04)

KASKA 90%(NuFact04)

→- for →anti-

sin22

22

Disappearance Ereconstruction resolution

Good resolution of Edetermination is critical to observe depth of the dip (measure of sin22)

QE

inelastic

E~60MeV<10% meaurement

E(reconstructed) – E(true)

1-sin22

non-QEresolution

m2

+ 10% bin High resolution : less sensitive to systematics

23

Precision measurement of 23 , m223

possible systematic errors and phase-1 stat.

•Systematic errors• normalization (10% （ 5%(K2K))• non-qe/qe ratio (20% (to be measured))• E scale (4% (K2K 2%))• Spectrum shape (Fluka/MARS →(Near D.))• Spectrum width (10%)

OA2.5o

(sin22)~0.01 (m2

23) <1×10-4 eV2

24

T2K Physics Sensitivity

Stat. only

--68%CL--90%CL--99%CL

Goal(sin22)~0.01 (0.08 MINOS EPS2007)

(m2)~<5×10-5 eV2

(OA2.5(OA2.5))

disappearance

Daya Bay 90%(NuFact04)

CHOOZ90%

>10 times improvement from CHOOZNeutrino ↔ Anti-neutrino, Reactor

e appearance(Strong dependence )

sin2213

25

Status of JPARC

26

Materials and Life ScienceExperimental Facility

Hadron Beam Facility

Nuclear Transmutation

J-PARC Facility

J-PARC = Japan Proton Accelerator Research ComplexJoint Project between KEK and JAERI

3 GeV Synchrotron(25 Hz, 1MW)

Linac

(350m)

50 GeV Synchrotron

(0.75 MW)

500 m

Neutrino to Kamiokande

27Upstream of Linac Tunnel

NeutrinoTunnel

50 GeV Tunnel

From 3 GeV toMaterials and Life

Middle of Linac Tunnel

From Linacto 3 GeV

3 GeVExtraction Point

TunnelTour

JPARC

2828

Preparation SectionPreparation Section

SCFM at ARC SectionSCFM at ARC Section

Target-Horn SystemTarget-Horn System

Target StationTarget Station

Decay VolumeDecay VolumeBeam DumpBeam Dump

Final Final FocusingFocusingSectionSection

Muon MonitoriMuon Monitoring Pitng Pit

Near Neutrino DetectorNear Neutrino Detector

295km to 295km to Super-KamiokandeSuper-Kamiokande

The Neutrino Beam-LineThe Neutrino Beam-Line

100m100m

29

Full Reconstruction (October 2005 – April 2006)

~6000 ID PMTs were produced from 2002 to 2005 and were mounted from Oct.2005 to Apr.2006.

All those PMTs were packed in acryic and FRP cases.

Mount PMTs on a floating floor.

Pure water was supplied and SK-III data taking has been running since July 11, 2006.

30

Schedule of T2K

• Possible upgrade in future

• 4MW Super-J-PARC + Hyper-K ( 1Mt water Cherenkov)

– CP violation in lepton sector

– Proton Decay

2004 2005 2006 2007 2008

SK full rebuild

T2K construction

April 2009commissioning

K2K

2009

Linac

MR

31

Next stepMany possibilities

• Intensity Upgrade of MR

• R/D for upgrade/replacement of SK with a new hyper massive detector

32

CPV and mass hierarchyIF has reasonable value

Funding agency

33

CP Asymmetry

)r ,σσr(

r

rr ,

r

rr ,

'P'P

'P'P'A e

μ

eσ

22

2

''

'21'

''

''

)()(

)()(

PP

PA

rrPrrP

rrPrrP

PP

PPA

ee

eeCP

cross section, detection efficiencies ratios for e/differences in neutrino and anti-neutrino

Studied by T.Kobayashi

34

Contamination of wrong sign components

Rate for is factor ~3 smaller than anti- due to cross section.

beam

beam

wrong sign

right sign

35

Cross sections

36

CP asymmetry in T2K

=/412=/8

ACP~Aobs-0.04+0.1matter corr.

cor.

matter

Pure CPV

Both correction need to beestimated at ~10% level

37

Water Cherenkov Detector

1st Phase (2009~, ≥5yrs)Super-Kamiokande(22.5kt)

2nd Phase (201x~?)Hyper-Kamiokande(~540kt)

Reach: p(e+0)/B 1035 yr p(K+)/B 1034 yr

Proton decay

e+π0

νK+

and other modes

38

Other Possible choice

?

39

Sensitivity for CPV in T2K-II

no BGsignal stat only

(signal+BG) stat only

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

stat+10%syst.

CHOOZ excludedsin2213<0.12@m31

2~3x10-3eV2

T2K 3 discovery

3 CP sensitivity : ||>20o for sin2213>0.01 with 2% syst.

4MW, 540kt2yr for 6~7yr for

sinsin

2sin

4 13

12212

E

mACP

m212=6.9x10-5eV2

m322=2.8x10-3eV2

12=0.59423=/4

T2K-I 90%

40

Proton decay limit from Super-K ~100k ton year already

2.9x1030 yr (‘minimal’ SUSY SU(5) )

Proton Decay may be there, just around the cornerUltimate GUTs phenomena

41

T2K to Korea ?

Korea J-PARC

hep-ph/0607255

L=1000-1200km, =1.0-4.0

42

Nova at FNAL