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100830 Neutrino Summer School @Tokai. Superbeam long baseline experiments. Takashi Kobayashi KEK. n e. n m. n t. 3 flavor mixing of neutrino. Flavor eigenstates. Mass eigenstates. m 1. Unitary matrix. m 2. m 3. 6 parameters q 12 , q 23 , q 13 , d - PowerPoint PPT Presentation
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Superbeam long baseline experiments
Takashi KobayashiKEK
100830Neutrino Summer School@Tokai
2
3
2
1
MNSU
e
10000
0010
0
00
001U 1212
1212
1313
1313
2323
2323MNS cssc
ces
esc
cssc
i
i
e
Flavor eigenstates m1
m2
m3
Mass eigenstates
6 parametersq12, q23, q13, Dm12
2, Dm232, Dm13
2)sin(s ),cos(c ijijijij qq
3 flavor mixing of neutrino
Unitary matrix
2
Dmij=mi2-mj
2
T.Kobayashi (KEK) 3
Known and Unknowns
OR
Solar & Reactor• q12~33o
• Dm122~0.00008eV2
Atomspheric + Acc• q23~45o • Dm23
2~0.0025eV2
Unknown!• q13<10o
• (Dm132~Dm23
2)?• ???
1
2
3
Mass hierarchy
e??
4
Unknown properties of neutrino
4
q13? Last unknown mixing angle T2K, NOvA, Double Chooz, RENO, DayaBay
CP invariance ? Mass hierarchy ?
Absolute mass Tritium beta decay, double-beta
Majorana or Dirac? Double-beta
Next generation accelerator based expriemtns
Toward unraveling the mystery of matter
dominated universe
5
Sakharov’s 3 conditions
To generate Baryon asymmetry in the unverse There is a fundamental process that violates
Baryon number C and CP invariance is violated at the same
time There is a deviation from thermal
equilibrium acting on B violating process
6
Toward origin of matter dominated universe
Quark sector CPV is found to be not sufficient for reproducing present baryon content
Scenario for baryogenesis through lepton CP violation: Leptogenesis CPV in lepton sector is responsible for B genesis
CPV in neutrino oscillation could provide a key to unravel mystery of origin of matter
7
Let’s find CPV in lepton sector I give you
1000 億円 or 1.2 Billion USD 755M GBP 55 Billion INR 1,401 Billion Won 2,130 Billion Peso 7.9 Billion 元 918 Million Euro 35 Billion Ruble 1.2 Billion CHF
8
Let’s design an experiment to search for CPV in lepton sector
If you find any good idea, let’s write a paper!
One condition: Within 10years
How? …. : Q1 Do we really need oscillation phenomena to
probe CPV?? Can’t we attack CPV in an experiment which
fit in an experimental hall like such as Kaon CPV or B CPV
Why??
9
Measuring CPV in quark sector
Through loop diagram Amplitude (m∝ u,c,t/MW)2
Please calculate Since quark is heavy (especially top), this
process becomes measureable10
W W
s,b
d
u,c,t
u,c,ts,b
W
u,c,t
VCKM VCKM
VCKMVCKM VCKMVCKM
How about lepton sector?
Amplitude (m∝ /MW)2
Standard model process STRONGLY suppressed Thus, good field to search for physics beyond
standard model
11
W
e,,
VMNSVMNS
e
gExample: eg
Oscillation
12
l l’
1
2
3
i
liitiE
liet
i
liimtiE
lmiet
MNSliU
Oscillation (cont)
13
i
liimtiE
lmiet
If Ei are same for all mass eigenstates E
mliEt
lmiEt
iliim
iEtlm
ee
et
Ei’s are same, no oscillation, in other word, Ei’s are different, we can probe mixing matrix through oscillation
Difference of Ei, ie, phase advance difference is essential
jiljmjlimi
tEEilmml UUUUetP ji
,
**2
)100()1(~ 2/)( 2
kmOLOee ELmitEEi ijji D
222jiij mmm D For Dm2~10-3eV2
14B.Kyser, in this SS
Q2: What oscillation process is best?
OK, now, we somehow understand we need (long baseline) oscillation phenomena to probe matrix elements and attack CPV.
What type of oscillation is best? Fundamental physics reason Experimental feasibility
15
Disappearance ? Appearance?
16
i
liimtiE
lmiet
ili
tiE
iliil
tiEll
Ue
et
i
i
2
Oscillation probability
Disappearance case
There is no place for complex phase in UMNS to appear
Disappearance has no sensitivity on (standard) CPV
Appearance Conventional beam (~GeV)
e Not yet discovered
Dominant oscillation mode
Neutrino factory/Beta beam (~10GeV) e e
17
Next talks
e vs appearance
18
Oscillation probability (w/ CPV)
sin2 AAP
Relative effect of CPV
AAACPCCPV sinsin/ 2
CP conserved part
CPV part
case, probability A sin∝ 22q23, is known to be large, relative effect of CPV
becomes small Also experimentally, identification of nt (out of lots of nm interactions ) is
not easy
For nue appearance, A sin∝ 22q13 is known to be small Large CPV effect expected
Matter effect
19
e
Z
e
X X
e
W
e-
e- e
Z
X X
Z
X XNC
Interactions through propagation in matter
CC
Matter effect
20
e
tot
e
Hdtdi
00000000
1
3
2
1 W
MNSMNStot
VU
EE
EUH
Relative size of effect E∝ Change sign when Dm2 sign
change: Can probe sign Change sign when ⇔bar:
Fake CPV effect
21
Oscillation probabilities
qq ELmP e /27.1sin2sinsin 213
213
223
2 D
qq ELmP x /27.1sin2sincos1 223
223
213
4 D
q ELmP xe /27.1sin2sin1 213
213
2 D
contribution from Dm12 is small
e appearance (LBL/Atm)
disappearance (LBL/Atm)
e disappearance (Reactor)
D
DDD
223
213
223
212
mL
Emmm
when
12
3
Dm232
(No CPV & matter eff. approx.)
~1
~0.5
≪1
Pure q13 and Dm132
q13 and Dm132
q23 and Dm232
22
e appearance & CPV
, a-a for e
]GeV[]cmg[][eV1056.7 3
25 Ea Matter eff.:
CP-odd
qq sin
sin2sin
13
12212
D
ELm
PPPPACP
Solar
Main
Matter
# of signal sin∝ 2q13 (Stat err sin∝ q13),CP-odd term sin∝ q13
Sensitivity indep. from q13
(if no BG & no syst. err)
23Takashi Kobayashi (KEK), PAC07
23
All mixing angle need to be non-zero
, a-a for e
]GeV[]cmg[][eV1056.7 3
25 Ea Matter eff.:
CP-odd
Leading
132312sin sss CPV effect
(where sinq12~0.5, sinq23~0.7, sinq13<0.2)
+ other terms..
Same as Kobayashi-Maskawa model which require 3x3 to incorporate CPV
24
CPV vs matter effect
295km 730km
)( ePP )( ePP
Smaller distance/lower energy small matter effectPure CPV & Less sensitivity on sign of Dm2
Combination of diff. E&L help to solve.
e osc. probability w/ CPV/matter
@sin22q13=0.01
Lepton Sector CP Violation
Effect of CP Phase δ appear as– νe Appearance Energy Spectrum Shape *Peak position and height for 1st, 2nd maximum and minimum *Sensitive to all the non-vanishing δ including 180° *Could investigate CP phase with ν run only
– Difference between νe and νe Behavior
3
2
1
231323122313122312231312
231323131223122313122312
1312131312
ccsccssesscscescssseccsscecssesccc
ii
ii
ie
25
How to do experiment?
OK, we now understand Importance of CPV in lepton sector Necessity of oscillation to probe CPV What process is suited for CPV measurement Behavior of oscillation probabilities and
relevant physicsSo, now, let’s consider more on experimentation!
26
27
Super Beam
Conventional neutrino beam with (Multi-)MW proton beam (Fact)
Pure beam ( 99%)≳ e ( 1%) from ≲ pe chain and K decay(Ke3) / can be switched by flipping polarity of focusing
device
ProtonBeam
Target FocusingDevices
Decay Pipe
Beam Dump
p,K
Strongly motivated by high precision LBL osc. exp.
28
High intensity narrow band beam-- Off-axis (OA) beam --
(ref.: BNL-E889 Proposal)
qTargetHornsDecay Pipe
Far Det.
Decay Kinematics
Increase statistics @ osc. max.Decrease background from HE tail
1/gp~q Ep(GeV)
E(GeV)
E(G
eV)
5
12
]mrad[30]GeV[max
q E
flux
/ flux for CPV meas.
-15%@peak
1021POT/yr
Sign flip byjust changinghorn plarity
Example
50GeV protonAt 295km
Cross sections Cross section E∝
Higher energy higher statistics
Anti-neutrino cross section smaller than neutrino by ~1/3 Why? Take ~3 times more
time for anti-neutrino measurements to acquire same statistics as neutrino
31
ep0
Back ground for e appearance search• Intrinsic e component in initial beam
• Merged p0 ring from interactions
e appearance search
“Available” technologies for huge detector
Liq Ar TPC Aim O(100kton) Electronic “bubble chamber”
Can track every charged particle Down to very low energy
Neutrino energy reconstruction by eg. total energy No need to assume process type Capable upto high energy
Good PID w/ dE/dx, pi0 rejection Realized O(1kton)
Water Cherenkov Aim O(1000kton) Energy reconstruction
assuming Ccqe Effective < 1GeV
Good PID (/e) at low energy Cherenkov threshold Realized 50kton 32
Good at Wideband beam
Good at low E (<1GeV) narrow band beam
Neutrino Energy E reconstruction in Water Cherenkov
CC quasi elastic reaction
q
cospEm2mEm
EN
2N
+ n → + p
-
p
(E, p)q
QE
inelastic
0
0 .5
1
1 .5
2
2 .5
3
3 .5
4
4 .5
0 1 2 3 4 5E (G e V )
c
ross
sec
tions
(10
cm)
-38
2
In e la s t ic
C C q e
+ n → + p + p
-
p
(E, p)ql
p
2 approaches for CPV (and sign(Dm2) ) Energy spectrum measurement of appeared e
Only w/ numu beam (at least early part) Measure term cos∝ (and sin)
Assume standard source of CPV ( in MNS) Cover 2nd oscillation maximum (higher sensitivity on CPV)
Higher energy = longer baseline favorable Wideband beam suited Liq Ar TPC is better suited
Difference between P(numunue) and P(numubar nuebar) Measure term sin∝ Not rely on the standard scenario
34
Angle and Baseline
OA3°
OA0°OA2°
OA2.5°
fl
ux• Off-axis angle– On-Axis: Wide Energy Coverage, ○Energy Spectrum Measurement ×Control of π0 Background– Off-Axis: Narrow Energy Coverage, ○Control of π0 Background ×Energy Spectrum Measurement → Counting Experiment
• Baseline– Long: ○ 2nd Osc. Max. at Measurable Energy × Less Statistics ? Large Matter Effect– Short: ○ High Statistics × 2nd Osc.Max.Too Low Energy to Measure ? Less Matter Effect
(E/L)
CP=90CP=270
CP=0
Dm312 = 2.5x10-3 eV2
sin22q13 = 0.1No matter effects
νμ νe oscillation probability
Osc
illat
ion
prob
abili
ty
35
“Available” beams
36
37
FNAL possible future Plan
38
CERN future possibilities
39
Present accelerator complex Various POSSIBLE scenarios
Under discussion
CERN possibilities
40
Okinoshima
658km0.8deg. Off-axis
KamiokaKorea
1000km1deg. Off-axis
295km2.5deg. Off-axis
Possible scenarios in Japan
41
Okinoshima
658km0.8deg. Off-axis
•Cover 1st and 2nd Maximum•Neutrino Run Only 5Years×1.66MW•100kt Liq. Ar TPC
-Good Energy Resolution-Good e/π 0 discrimination
•Keeping Reasonable Statistics
Scenario 1 δ=0°
νeSpectrum
Beam νe
Background
CP Measurement Potential
NP08, arXiv:0804.2111
δ=90°
δ=180° δ=270°
sin22θ13=0.03,Normal Hierarchy
3s
42
295km2.5deg. Off-axis<E>~0.6GeV
TokaiKamioka
•Cover 1st Maximum Only•2.2Years Neutrino+7.8Years anti-Neutrino Run 1.66MW•540kt Water Cherenkov Detector
Scenario 2
K.Kaneyuki @NP08
=0 =p/2
Er
ec
Er
ecEr
ec
Er
ec
+ BG+ee BG
signal+BG
sin22θ13=0.03,Normal Hierarchy
sin2 2
q 13
Frac
tion
of
3s
3s
CP sensitivity
sin22θ13
deg.
43
Site studies in Europe
44
45
US Superbeam Strategy: Young-Kee Kim, Oct. 1-3, 2009
NSF’s proposedUnderground Lab.
DUSEL
1300 km
Project X: ~2 MW
700kW15kt Liquid Scintillator
Under construction
NOvA
~50 kton Liquid Ar TPC~300 kton
Water Cerenkov
MiniBooNESciBooNE
MINOSNOvA
MINERvAMicroBooNE
735 km2.5 msec810 km
Combination of WC and LAr
FNAL possibilities
FNAL-DUSEL potential
To realize the experiments
Need Finite (reasonable) q13 T2K, NOvA,
Reactors! High power (>MW) neutrino beam Huge high-sensitivity detector YOUR CHALLENGE OR YOUR NEW IDEA!
48
Summary Properties of neutrino are gradually being revealed However still yet far unknown than quarks
CPV, mass hierarchy, etc. Especially, CP symmetry could be a critical key to answer
the fundamental question: What is the origin of matter in the universe
Future superbeam long baseline oscillation experiments have chance to discover CPV effect (if q13 is large enough to be detected in present on-going experiments)
Already many studies and developments (beam, detectors) are being made around the world to realize the experiments
Lot’s of challenges and funs forseen Let’s enjoy!
49
1000km1deg. Off-axis
295km2.5deg. Off-axis
Scenario 3 •Cover 2nd Maximum @ Korea•Cover 1st Maximum @ Kamioka•5Years ν+5Years ν Run 1.66MW•270kt Water Cherenkov Detector each @ Korea, Kamioka
F.Dufour@NP08(study is initiated by M.Ishitsuka et. al. hep-ph/0504026)
50
Comparison of Each ScenarioScenario 1Okinoshima
Scenario 2Kamioka
Scenario 3 Kamioka Korea
Baseline(km) 660 295 295 & 1000
Off-Axis Angle(°) 0.8(almost on-axis) 2.5 2.5 1
Method νeSpectrum Shape Ratio between νe νe Ratio between 1st 2ndMaxRatio between νe νe
Beam 5Years νμ,
then Decide Next 2.2 Years νμ,
7.8 Years νμ,
5 Years νμ,
5 Years νμ,
Detector Tech. Liq. Ar TPC Water Cherenkov Water Cherenkov
Detector Mass (kt) 100 2×270 270+270
51
Additional requirement forfar detector optimization
• Proton Decay Discovery Performance
• Realization of the huge detector– Test of the key components– Experimentally prove the detector performance
• if necessary, good prototyping (able to predict Huge Detector Performance well) is important• Test with the beam is important
KEK started R&D for Huge Liq. Ar TPC with ETH Zurich52 See Maruyama’s talk
53
Constraints on Dm122, q12
太陽&原子炉ニュートリノ
= 0.410.02DataSSM
SK-I (1996~2001)
)()(06.068.1
)(15.0)(22.035.215.0
)()(21.094.4
08.009.0
38.034.0
syststat
syststat
syststat
e
e
e
sec/cm/10 26
5454
12GeV PS50 kton WaterCherenkov detector
250km
Pure beam (99%)w/ <E>~1.3GeV
K2K(1999~2004)
735km
MINOS(2005~)
q23, Dm232: 大気ニュートリノと加速器実験
SK(1996~)
すべて “消失”実験
M.Diwan, Venice, Mar.2009
q23 ~45o
Dm232 ~0.0024eV2
55
q13 の上限値原子炉反電子ニュートリノ消失実験
Chooz
qq ELmP e /27.1sin2sinsin 213
213
223
2 D
ijijijij sandcwhere qq sin,cos
1000cs0sc
c0iδes010
iδes0c
cs0sc0001
UUUUUUUUU
U 1212
1212
1313
1313
2323
2323
τ3τ2τ1
μ3μ2μ1
e3e2e1
li
ilil U If neutrinos have mass:
ELmmm
Pe
4/and/ where
sin2sincos
2sincos2sin2sincoscos2sinsin2sin2sincossin2sin
sin2sin2sin
231
231
221
212
223
22
23121313
323121313
223
213
2
DDDD
D
DDD
D
qqqqqqqq
~0.03 ~p/4And sin22q13 < ~0.14
Three neutrino mixing.
T.Kobayashi (KEK) 5757
q13 の測り方加速器ニュートリノによる 13
• ミューニュートリノ: <E> ~ O(GeV) e 出現実験
• P(e) = sin2q23 ・ sin22q13 ・ sin2(1.27Dm231L/E) + many terms (incl. )
Appearance measurement
統計 ( =ビームパワーx検出器サイズ ) 勝負
原子炉ニュートリノによる 13
• 反電子ニュートリノ: <E> ~ a few MeV e 消失実験
• P(ee) = 1- sin22q13 ・ sin2(1.27Dm231L/E) + O(Dm2
21/Dm231)
Almost pure measurement of q13.
消失信号が小さい 系統誤差勝負
58Takashi Kobayashi (KEK), PAC07
58
D
]GeV[]km[]eV[27.1sin2sin)()(
22222
q
ELmtP
massm1
m2
2
1
cossinsincos
qqqq
Neutrino Mixing22
21
2 mmm D
L:flight dist 、 E:neutrino energy
Neutrino Oscillation (in 2flavor approx.)1-
P(
)
L=250km, Dm232=3x10-3eV2
1 2
Weak eigenstates Mass eigenstates
sin22q
Dm2
qq sinecose)( 22
21
22
21 L
EmiL
Emi
t
現象 元の種類のニュートリノが減
少 (“Disappearance”) 別の種類のニュートリノが出
現 (“Appearance”) 振動に特徴的なエネルギー分
布
Disappearance ( 消失 )
Probability to change flavor
qq sincos)0( 21
sin22q
Dm2
Appearance ( 出現 )
E(GeV)
59
Long baseline osc. experiments 1st phase experiments (Now)
Confirmation of atm. results K2K(1999~)/MINOS(2005~)/ICARUS/OPERA(2006~)
2nd phase experiments (Now~10yrs) Discovery of e appearance Designed & Optimized aft. SK atm ~MW beam w/ ~50kton detector
T2K-I (approved. 2009~)/NOA (2009?~) / (C2GT) 3rd phase experiments(10~20yrs?)
CP violation and mass hierarchy thru e app. Typically Multi-MW beam & Mton detector 2nd phase is critical step to go
Classification byG.Feldman @SB WS@BNL
“Super Beam”Experiments
() ()
Quest for the Origin of Matter Dominated Universe
One of the Main Subject of the KEK Roadmap
Discovery of Lepton CP Violation
Proton Decay
Discovery of the e Appearance
Neutrino Intensity Improvement
Huge Detector R&D
T2K(2009~)
Water Cherenkovv
Liquid Ar TPC
Establish Huge Detector
TechnologyConstruction of Huge Detector
Accelerator Based Neutrino Project in JapanK2K T2K 3rd Generation Exp.
(KEK Roadmap)High Power Proton Synchrotron
KEK PS12GeV 0.005MWExisting
J-PARC MR30GeV up to 0.75MWBrand New
J-PARC MR 30GeV 1.66MWTechnically Feasible Upgrade
Neutrino Beamline K2K Neutrino BeamlineBrand New
J-PARCNeutrino Beamline Brand New
J-PARCNeutrino Beamline Existing
Far Detector Super KamiokandeExisting at KAMIOKA
Super KamiokandeExisting at KAMIOKA
Brand New-Detector Technology ?-Place ? (Angle and BaseLine)
1st Priority Physics Case
Neutrino Oscillationνμ Disappearance
Neutrino Oscillationνμνe
Lepton Sector CP Violation+ Proton Decay Search
Able to concentrate on Far Detector issue toward the 3rd Generation Experiment after T2K startup61