Post on 04-Jan-2016
description
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
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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
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e oscillation probability in sub-GeV neutrinos
sin2213=0.01
matter
total13CPCPsolar
Depends on manyparameters
10
Accelerator NeutrinosNear future
T2K
Nova
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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
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Beam energy QE is the best known process
1 10 E
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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
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+ 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)
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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
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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
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Status of JPARC
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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.
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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
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Next stepMany possibilities
• Intensity Upgrade of MR
• R/D for upgrade/replacement of SK with a new hyper massive detector
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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
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Nova at FNAL