December 13, 2018
@Media Center, Osaka City University, Japan
International Symposium in Honor of Professor Nambu
for the 10th Anniversary of his Nobel Prize in Physics

Neutrino CP violationinthe J-PARC neutrino experiments
T. Nakaya (Kyoto University)1南部陽一郎物理学研究所HPより

2

Neutrinos
u

c

t

d

s

b

lepton Small massquark

 Week interactions only

e

µ

τ

νe νµ

ντ

 Origin in physics beyond the standard

model?
 Mixing
 3 neutrinos are mixed

 Diﬀerent mixing patterns from that of quarks

neutrinos What symmetry exists?

 No experimental information on the CP

symmetry (between a particle and the antiparticle)

ν1

ν2

ν3

Much exciting to study neutrinos after the
discovery of neutrino oscillation in 1998
3

Abundant particles in our universe•
4•Tν=1.95K#Nν=112 3cm-3

Our world is invisible•

Dark Energy•

Dark Matter•

Neutrinos•

Cosmic Neutrino Background (0.03%)
Credit: NASA/WMAP Science Team•

(Relic) Supernova Neutrinos•

Solar Neutrinos•

Atmospheric Neutrinos•

Geo-neutrinos•+ We can make neutrinos by reactors
and accelerators.
5

Image of our universe
Dark Matter

Neutrinos

Matter6

CP Violation
 In the Big-Bang, particles and anti-

particles were produced in same amounts.
 Later, they would annihilate.
 e+ + e- → photons
 p + pbar → photons

 Violation of the symmetry between aparticle and the anti-particle.
 CP violation

CP violation is necessary for particles only tosurvive and to form our universe.
7Probing Neutrino CPV•

Neutrino Oscillations with CP violation [Mainly Experimental study]•

Weak (ﬂavor) state•

3 generations ➡ Imaginary Phase in a mixing matrix•••

Mass state[Neutrino] PMNS matrix 〜 [Quark] CKM matrix

Example: P(νμ→νe)

P(νμ→νe)Heavy Majorana Neutrino (N) if exists [Theoretical study]•

NOT easy to access (very very diﬃcult)•

The decay of N••

P(N→lL+φ)P(N→lL+φ)

Or, the oscillations of N
8

Leptogenesis and Neutrino CPV••

Saharov conditions for Baryon Asymmetry•[B] Baryon Number Violation•[CP] C and CP violation•[T] Interactions out of thermal equilibrium

Leptogenesis and Low Energy CP violation in Neutrinos•[B] Sphaleron process for Δ(B+L) 0•[CP] Heavy Majorana Neutrino decay and/or Neutrino oscillations•[Phys. Rev. D75, 083511 (2007)] |sinθ13sinδ|>0.09 is anecessary condition for a successful “ﬂavoured” leptogenesis
with hierarchical heavy Majorana neutrinos when the CP
violation required for the generation of the matter-antimatterasymmetry of the Universe is provided entirely by the Dirac CP
violating phase in the neutrino mixing matrix.
•sinθ13〜0.15 ➡ |sinδ|>0.6
9

How to measure neutrino CPV?
•

Measure P(νμ→νe)/P(νμ→νe) 1•or P(νμ→ντ)/P(νμ→ντ) 1 because of P(νμ→νμ)/
P(νμ→νμ) =1•

Or, precisely measure P(νμ→νe) with the assumption of 3 lightneutrinos. Within the framework of 3 neutrinos, CP violation will begoverned by the imaginary phase δCP in the neutrino mixing matrix.

•

Matter eﬀect can mimic the genuine CP violation. The measurementof the matter eﬀect is equally important to study neutrino CP
violation. The matter
eﬀect
determine
the neutrino mass ordering.
What
we alreadyknowθ12 = 34.4° ± 1.3°
θ 23 = 45° ± 8° (90%CL)
θ13 ≤ 12° (90%CL)§ 0.8 0.55 < 0.21·¨¸
U MNS ≈ ¨ − 0.4 0.6
0.7 ¸
¨ 0.4
0.6
0.7 ¸¹
©

δ=?

10

O
R
~2.4x10 eV-3~7.6x10-5eV22~2.4x10-3eV2~7.6x10-5eV2

2
2
2
2
2
×(C12
C23
+ S12
S13
S23
+ 2C12 C23 S12 S13 S23 cos δ) · sin2 ∆12

Formula of Oscillation Probability with CP violation
22
2
P (νµ → νe) = 4C13
S13
S23
· sin2 ∆31 Leading

CP violating (flips sign for ν)

2+8C13
S12 S13 S23 (C12 C23 cos δ − S12 S13 S23 ) · cos ∆32 · sin ∆31 · sin ∆212−8C13
C12 C23 S12 S13 S23 sin δ · sin ∆32 · sin ∆31 · sin ∆21

2
2
2
2
2
2
2
+4S12
C13
(C12
C23
+ S12
S23
S13
− 2C12 C23 S12 S23 S13 cos δ) · sin2 ∆21
Solar
aL
2
2
2
2
−8C13 S13
(1 − 2S13 ) · cos ∆32 · sin ∆31
12 S23 ·4Eν
aMatter effect
2
2
2
2
2
+8C13 S13 S23(1 − 2S13 ) sin ∆31
2
∆m13

0.06

2
Leading(θ13)
"
%
Δm
L
2
2 31 2
2
2
2
2
4
2
295km
θ 23 sin
θ1313
sin
Leading
P (νe → νsin
1−2
4C
S13 ·$(C12sin' ∆13 + S12
sin
∆
)
−
4S
C
C
sin
∆12
e) =
23
12 12 13
Total
0.04
# 4E &
Solar
0.02
CPV
2 L/4E , respectively, and Matter
2 ] = 7.56 ×
where Cij , Sij , ∆ij are cos θij , sin
θ
,
∆m
a[eV
ij
ν
2
2 ij
0
sin
2
θ
sin
2
θ
Δm
L
Δm
2
2
31
21 L
10−5 ×12ρ[g/cm233 ]sin
×E].
2νθ[GeV
sin
sin
sin
δ
13
CPV
2sin θ13
4E
4E
CPC(cosδ)
-0.02
~11.8
(6.4
from
1/sinθ
)~0.03
132
π Δm21
sin 2θ12 sin 2θ 23 E1st max~
22θ13=0.1,δ=π/4)-0.04[leading] sin δ(sin2
2
4 Δm32 sin θ 23 sin θ13
E-0.06
E1st max
01
2~ 0.27 × [leading] ×× sin δEν (GeV)
E
2

27%

2

22

•Energy dependence is important.
11

K2K & T2K Experiments
T2K (2009~)

Kamioka

250 kmK2K (1999~2005)

12

Tokai

Accelerator Neutrino ExperimentΦνND(Eν）
Big Far detectorΦνSK(Eν）

High Resolution
Near detector

ν, ν, ν, νIntense beamπ, π, π, π, Κprotons

oscillation

J-PARC
J-PARC

SuperKamiokande
KamiokandeSuper“far”detector
detector(FD)
(FD)
“far”

Kamioka
Kamioka

Tokai
Tokai

295 km295 km~500 collaborators fromcollaboratorsfrom58~500institutions,
12 nations

Intense ~600 MeV νµ beam for
Intense
~600
MeV
ν
beam
for
µ
neutrino oscillation studies

oscillation
High sensitivity
searchstudies
for θ13•neutrino

58 institutions, 12 nations

Credit: Super-K collaboration

The$T2K$Collabora>on$
Italy$
Poland$Spain$
Canada$$ INFN,$U.$Bari$
IFJ$PAN,$Cracow$
IFAE,$Barcelona$
TRIUMF$$ INFN,$U.$Napoli$
NCBJ,$Warsaw$
IFIC,$Valencia$
U.$Alberta$
INFN,$U.$Padova$
U.$Silesia,$Katowice$$
U.$B.$Columbia$
INFN,$U.$Roma$
U.$Warsaw$
Switzerland$
U.$Regina$$
Warsaw$U.$T.$
ETH$Zurich$
U.$Toronto$
Japan$
Wroklaw$U.$
U.$Bern$
U.$Victoria$
ICRR$Kamioka$$
U.$Geneva$
U.$Winnipeg$
ICRR$RCCN$$$
York$U.$
Kavli$IPMU$
Russia$United$Kingdom$
$
KEK$
INR$
Imperial$C.$London$
France$
Kobe$U.$$
Lancaster$U.$
CEA$Saclay$
Kyoto$U.$
Oxford$U.$
IPN$Lyon$
Miyagi$U.$Edu.$
Queen$Mary$U.$L.$
LLR$E.$Poly.$
Osaka$City$U.$
STFC/Daresbury$
LPNHE$Paris$$
Okayama$U.$
STFC/RAL$
Germany$
Tokyo$Metropolitan$U.$ ~500$members,$$ U.$Liverpool$
Aachen$U.$
U.$Tokyo$

59$InsLtutes,$$
11$countries$
14$
U.$Sheﬃeld$
U.$Warwick$$
USA$
Boston$U.$
Colorado$S.$U.$
Duke$U.$Louisiana$S.$U.$
Stony$Brook$U.$
U.$C.$Irvine$
U.$Colorado$
U.$Pidsburgh$
U.$Rochester$
U.$Washington$
$
$
$
8$

Neutrino oscillation experiments in Japan
(ー)

(ー)

Intense Neutrino Beam for νμ→νe study

J-PARC
Super-K

Super KamiokandeSuper“far” detector (FD)“far”

Kamioka

Tokai
295 kmHyper-K(2026~)• 500 kW (today)• collaborators~1MW (2022)
~500
from
1.3 MW (2026)
nation58 •institutions,
12 nations

Seamless program withphysics
results
Intense ~600timely
MeV νµµ beamforneutrino oscillation studies•• High sensitivity search for θ13
13
22•• Precision measurement of θ23,
23, Δm 23
23• 22.5 kton (Super-K, ~2026)• 190 kton (Hyper-K,
2027~)
see “T2K“T2K Experiment”
Experiment”
seearXiv:1106.1238 submitted
submitted toto NIM
NIM15
A
arXiv:1106.1238
ACreatingT2K
an (offaxis)
neutrino beam
ν beam30 GeVa target (carbon)
producing
14 protons
GeVprotons~2 10hit
extracted
every secondary
2.5/1.3 mesons (π, K) which•30
decay to a terOary ν beam
 Collected 1.43 x 10 POT (2% of T2K goal)sec. directed to the carbon target.
µSecondaryπ(andK ) focused by three•
20
electromagnetic horns ( 250kA/320kA)•νμ beam from mainly π+→μ++νμ•νe (1~2%) in the beam come from K and μ
decays•Reversing the current of horns, Anti-neutrino
beam (νμ) can be produced

T2K uses a novel oﬀ‐axis beam technique: Oﬀ the primary neutrino beam direcOon,
neutrino energy spectrum is narrower, 816

νμ oscillated at 295 km

ND280
Near Detector @ 280m
from the target• INGRID @ on-axis (0 degree)• ν beam monitor [rate, direction, andstability]• ND280 @ 2.5 degree oﬀ-axis
Normalization of Neutrino Flux
✦ Measurement of neutrino cross sections.
•Dipole magnet w/ 0.2T
• P0D: π0 Detector• FGD+TPC: Target + Particle tracking• EM calorimeter• Side-Muon-Range Detector✦

17

T2K-Far Detector: Super-Kamiokande• Water Cherenkov detector with 50 kton mass (22.5 kton
Fiducial volume) located at 1km underground
Good performance (momentum and position resolution, PID,
charged particle counting) for sub-GeV neutrinos.
[Typical] 61% eﬃciency for T2K signal νe with 95% NC-1π041.4m

rejection
Inner tank (32 kton) :11,129 20inch PMT
Outer tank:1,885 8inch PMT•
Atmospheric ν● Data
− MC

39.3m

18

Neutrino Detection at SK Far Detector
Signal ("5 )Signal ("# )Background"5 CCQE"# CCQE"ℓ NC1i K

719

A door to Neutrino CP violation is opened• νμ→νe oscillation w/ Δmatm2 discovered by the T2K experiment• Indication in 2011 [PRL 107, 041801 (2011)]• Observation in 2013 [PRL 112, 061802 (2014)]
•

2011

T2K
νe

2013

T2K
νe

20

21

22

New T2K CPV Resultsin 2018
Ref. T2K 2017 CPV result is just published in PRL
PHYSICAL REVIEW LETTERS 121, 171802 (2018)
Editors' Suggestion

Featured in Physics

Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experimentwith 2.2 × 10 21 Protons on Target
K. Abe,48 R. Akutsu,49 A. Ali,20 J. Amey,17 C. Andreopoulos,46,27 L. Anthony,27 M. Antonova,16 S. Aoki,24 A. Ariga,2Y. Ashida,25 Y. Azuma,34 S. Ban,25 M. Barbi,39 G. J. Barker,58 G. Barr,35 C. Barry,27 M. Batkiewicz,13 F. Bench,27
V. Berardi,18 S. Berkman,4,54 R. M. Berner,2 L. Berns,50 S. Bhadra,62 S. Bienstock,36 A. Blondel,12,* S. Bolognesi,612
B. Bourguille,15 S. B. Boyd,58 D. Brailsford,26 A. Bravar,
C. Bronner,48 M. Buizza Avanzini,10 J. Calcutt,29 T. Campbell,823
S. Cao,14 S. L. Cartwright,43 M. G. Catanesi,18 A. Cervera,16 A. Chappell,58 C. Checchia,20 D. Cherdack,8 N. Chikuma,47

New T2K Data (3.16 E21 POT ← 2.2E21 POT)!-mode 1.51 x 1021 (47.83%)"̅ -mode 1.65 x 1021 (52.17%)

23 Jan. 2010 – 31 May 2018
POT total: 3.16 x 1021•

J-PARC Accelerator has achieved stable operation with ~500 kW beam power
24

Oscillation Analysis: Step 1
Neutrino-nucleus Interaction Model

Neutrino Flux Model
Flux (/cm2/50MeV/10 21p.o.t)

Neutrino Mode Flux at ND280

FGD2

TPC1

TPC2

1010
109
108

Events/(100 MeV/c)

FGD2

TPC3

1

2

3

4

5

6

7

8 9 10Eν (GeV)Fit to ND280 data constrains neutrino flux
parameters and interaction model parameters

Data / Sim.

FGD1

1011

0

ND280 Data

νµ
νµ
νe
νe

1012

25

ν -mode2500

Data
ν CCQE

2000

ν CC 2p-2h

T2K Preliminary

1500

ν CC Res 1π
ν CC Coh 1π1000ν CC Otherν NC modes500

ν modes

0
1.2
1.1
1.0
0.9
0.8

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Reconstructed muon momentum (MeV/c)

Challenges- Systematic uncertainties fromneutrino-nucleus cross sections -26

WAGASCI Collaboration
Institute for Nuclear Research of the Russian Academy of Science.
M. Antonova, A. lzmaylov, M. Khabibullin, A. Khotjantsev, A. Kostin, Y. Kudenko,
A. Mefodiev, O. Mineev, T. Ovsjannikova, S. Suvorov, N. Yershov
KEK
T. Ishida, T. Kobayashi
Kyoto University
S. V. Cao, T. Hayashino, A. Hiramoto, A. K. Ichikawa, A. Minamino, K. Nakamura,
T. Nakaya, K. Yoshida
Laboratorie Leprince-Ringuet, Ecole Polytechnique
A. Bonnemaison, R. Cornat, O. Draper, O. Ferreira, F. Gastaldi, M. Gonin, J. Imber,
M. Licciardi, T. Mueller, B. Quilain, O. Volcy
Osaka City University
Y. Azuma, T. Inoue, J. Harada, K. Kin, Y. Seiya, K. Wakamatsu, K. Yamamoto
University of Geneva
A. Blondel, F. Cadoux, K. Karadzhov, Y. Favre, E. N. Messomo, L. Nicola, S. Parsa,
𝑜𝑏𝑠
M. Rayner
University of Tokyo
𝐵𝐺
N. Chikuma, F. Hosomi, T. Koga, R. Tamura, M. Yokoyama
8 Institute
Institute of Cosmic-Ray Research, University of Tokyo
53 Collaborators
Y. Hayato

A01

WAGASCI
detector
WAGASCI Project
WAGASCI detector
Osaka City Univ.
Central detector + MRDs
Ken'ichi Kin

on behalf of the WAGASCI Collaboration

Muon Range Detectors
Neutrino
Frontier Workshop 2016
(MRDs)

Central detector

0.5 m

Slit

ν Xsec measurement

𝑁𝑜𝑏𝑠 − 𝑁𝐵𝐺
𝑋𝐻2𝑂 =
𝛷 ･ 𝑇𝐻2 𝑂 ･ 𝜀

𝑁 : Observed events
𝑁 : Background events
Φ: Neutrino flux
3D grid-like structure
𝑇𝐻2𝑂 : Number of nucleons (H2 2 Oε:Detection
efficiency
Scintillators
w/oslit
5.0 cm0.5 m

Gap btw. central detector and MRD
Background events can be rejectedby the information of TOF

5.0 cmCentral detector
2.5 cmEach module Goal of WAGASCI experiment

0.5 m

5

TargetMeasure neutrino cross sections of H2O and CH with 10% accuracy.
● Targetmass:
Measure the neutrino crosssectionratio0.5
btw.tonH2O and CH within 3% accuracy
27● Numberof channels: 1280 ch

11

WAGASCI Construction
Layer & module assembly work

4 sub-modules → One target module
Four scintillator layers→ One sub-module

Poster
WAGASCI
Construction(2)
Install into the water tank
- F. Hosomi
Now, we are preparing for constructing a new H2O module(U Tokyo)

Bundle fibers
Cutting WLS fibers

28

Light yield measurement by cosmic-rays

Oscillation Analysis: Step 2
Prediction at Super-K

Oscillation Probability Constrained by near detector

Fit to SK data to extract
oscillation parameter intervals

T2K Super-K Data

T2K Preliminary29

ν Mode νe Candidates

Observation at Super-K
Neutrino 1 μ-like ring

Neutrino 1e-like ring

Antineutrino 1 μ-like ring
T2K Preliminary

Antineutrino 1e-like ring Neutrino 1e-like ring + π30Predictions and Observation
Predicted Rates
Sample

•

δcp=π

Rates

e-like FHC

73.8

61.6

50.0

62.2

75

e-like+π FHC

6.9

6.0

4.9

5.8

15

e-like RHC

11.8

13.4

14.9

13.2

9

μ-like FHC

268.5

268.2

268.5

268.9

243

μ-like RHC

95.5

95.3

95.5

95.8

102

The number of observed events are largely in line with the predictions
after oscillations••δcp=-π/2 δcp=0 δcp=π/2

Observed

The e-like samples have rates most consistent with the δcp=-π/2
hypothesis

The observed μ-like rate in neutrino mode is lower than prediction•

consistent within statistical and systematic errors
31

(Simulation) Oscillation Parameter Sensitivities
Without the reactor experiment constraint on sin22θ13

Integrate out sin2θ13
dependence

Reactor constraint on sin2(2θ)13 (PDG2016)

Integrate out
sin2θ13 dependence

32

(Data) θ13 and δCP•

Fit without the reactor
constraint: closed contours inδcp at 90% CL•

The T2K value for sin2θ13 isconsistent with the PDG 2016•

Adding the reactor constraint
improves the constraint on
δcp average:

Reactor
1σ band

T2K Preliminary

With Reactor Constraint
T2K Preliminary

33

Measurement of δcp with reactor θ13
2σ CL Intervals

Best fit point:-1.82 radians in Normal Hierarchy

The 1σ CL confidence interval:

Normal hierarchy: [-2.44, -1.23] radians

The 2σ CL confidence interval:

Normal hierarchy: [-2.91, -0.85] radians
Inverted hierarchy: [-1.57, -1.16] radians•

CP conserving values (0,π) fall outside of the 2σ CL intervals
34

Δm232=+2.50×10-3eV2

0.4

IH
NOvA
at
Fermilab
Combined Appearance/Disappearance Results
Results

1σ

Combined

0.3

3σBest Fit

NOvA Preliminary
π
π
3π
μ
2 e
2
δ

0
2π
Precise measurement of P(νμ→ν ) and P(ν →νe)•

0.7

neutrino9.48
beam
×10 POT (ν)
Total events - antineutrino beam

NOvA FD25

sin22θ13=0.082

20

6.91×1020 POT (ν)

hy by 1.8
20

UO
sin θ23=0.59
2

15

LO
sin θ23=0.46
2

he IH at > 3

IH
2
Δm32=−2.55×10-3eV25

δCP= 0δCP= π20

4NH Lower octant
IH Lower octant

3

0.3

2

0.7

1

0.6

1σ

00
0.4

NH

Δm232=+2.50×10-3eV2δ = π/2

δCP= 3π/20CP
LatestResults from NOvA

40

IH Upper octant

0.4

0.3

30

NH Upper octant

0.5

2σ

3σ

Best Fit

NH

0.5

10

nd ⇡/2 in NH

5sin2θ23

80

CP

0.6

sin2θ23

70

Significance (⇥)

60

NOvA Preliminary

NOvA Preliminary

50

2σ

50

60

70

80

⇤
2
1σ

2σ
π
2

⇤
CP
Best
Fit

3σ
π

δCP

IH

3⇤
2

September
10, 2018
3π
2π

2⇤

28 /

2

talk at NEUTRINO 2018

Total events - neutrino beamPrefer normal hierarchy by 1.8• Neutrino:

Prefer upper octant

58 events observed with 15 background expected•ExcludeAnti-neutrino:
eventsobserved with 5.3 background expected= ⇡/2 in the18
IH at
>3

Weaklyaround ⇡/2 in NH(>4σpreferobservation)
Matthew Strait (UMN)

35
Latest Results from NOvA

September 10, 201828 / 38

Super-K
with
atmosphericν.
tting results with T2K constraint•

CP Violation Phase (δCP)

In addition to CP violation, it is also sensitive to mass hierarchy.

SK only(sin2 𝜃13 =SK+T2K
0.0219 ± 0.0012)
2
Δ𝑚21= 7.53 ± 0.18 × 10−5 ev 2 ,sin2 𝜃12 = 0.304 ± 0.014,
sin2 𝜃13 = 0.0219 ± 0.012

Normalhierarchy

Invertedhierarchy• best fit 4.18 (3.84)• slightly suggest nonzero δcp

2 2
2
2NH
• 2NH
( 𝜒-χ
−
𝜒
than
SK-only(-4.3)
Δχ2=χ
=-4.3
Δχ2=χ
-χ2IH=-5.2
IH
𝑁𝐻,𝑚𝑖𝑛
𝐼𝐻,𝑚𝑖𝑛 = −5.2 ) stronger• δCP still favor ~4.9(4.5) with stronger
talkconstraint
at NEUTRINO 2018
36

NuFIT 3.2 (2018)

Global FIT

15

Dc

2

10

I. M. Soler, Talk at NOW 2018

Conclusions

5

Comparison between di↵erent global fits
0
0.2

0.25

0.3

0.35

2

0.4

6.5

7

7.5

2
-5
2
Dm21 [10 eV ]sin q12

8

8.5

15

Capozzi et al.,[2]Salas et al.,[3]sin2 ✓12

0.307+0.013
0.012

0.304+0.014
0.013

0.320+0.20
0.16

sin2 ✓23

0.538+0.033
0.069

0.551+0.019
0.070

0.547+0.20
0.30

sin2 ✓13

0.02206+0.00075
0.00075

0.0214+0.0009
0.00070.0216+0.00083
0.00069CP

234+4331

234+41
32

218+3827m2
21
10 5 eV2

7.4+0.21
0.20

7.34+0.17
0.14

7.55+0.20
0.16

m2
31
10 3 eV22.494+0.033
0.031

2.455+0.035
0.032

2.50+0.03
0.03

Dc

2

10

Nufit[1]5[1] NuFIT 3.2 (2018), www.nu-fit.org

0

0.3

0.4

0.5

0.6

2

0.7 -2.8 -2.6 -2.4 -2.2
2
Dm32

sin q23

-3

2.2

2

[10 eV ]

2.4

2.6

2
Dm31

[2] F. Capozzi, E. Lisi, A. Marrone, and A. Palazzo, Prog.Part.Nucl.Phys. 102

2.8(2018) 48-72[3] P.F. de Salas, D.V. Forero, C.A. Ternes, M. Tortola, J.W.F. Valle, Phys.Lett.

15

B782 (2018) 633-640

NO
IO
10

Dc

2

•
5

0

0.015

0.02

2

0.025

sin q13

0.03

0

90

180

dCP

270

360

37

CP violation (w/ δCP~-π/2)
is preferable.

Prospect38

99% C.L.

5

5
90% C.L.

90% C.L.

0
−200
−100

0
−200

T2K-II∆ χ2 to e

99% C.L.

−100
0

0

True δ100
CP(°)
True δCP(°)

100
200

200

∆ χ2 to3σ C.L.

∆ χ2 to e

099% C.L.

5

5

90% C.L.

90% C.L.

0
−200
−100

0
−200

−100

0

0

True δ100
CP(°)
True δCP(°)

100
200

200

(b) Assuming
MH is known – measuredby
3σ sensitivity to CP violation
forthefavorable
parameters
based on(a) Assuming the MH is unknown. (b) Assuming the MH is known – measured byan outside experiment.
(a) Assuming the MH is unknown.
21• 20 10an outside
experiment.
Protons on
Targetwith the upgrade of J-PARC to•

FIG. 20: Sensitivity
to CP
violation
as a functionof true before
full T2K-II
exposure
1.3MW
(~10
year
long run)2026.
CP for the year
20: Sensitivity to CP violation as a function of true CP for the full T2K-II exposureof 2021⇥ 1021 POT with a 50% improvement in the e↵ective statistics, 2016 systematics are
• 50
more
eventswith
improvementsof the⇥ 10 POT
with %
a 50%
improvementin thee↵ective
statistics, 2016 systematics
are beam line and event
employed, and assuming that the true MH is the normal MH. The left plot is with assumpoyed, and assumingthat the true MH is the normal MH. The left plot is with assumpreconstructions.
tion of unknown mass hierarchy and the right is with known mass hierarchy. Sensitivities
of unknown mass hierarchy and the right is with known mass hierarchy. Sensitivities
2 systematic uncertainties.
~2/3
smallerat three •di↵erent
valuesofsin✓23 (0.43, 0.5 and 0.6) are shown.
932 that the T2K-II data is taken in roughly2
ree di↵erent values of sin ✓23 (0.43, 0.5 and 0.6) are shown.
933 (with true normal MH and CP =⇡/2)

POT&w/
2016
sys. errs.
20x10 POT7.8x10
w/ eff. stat.
sys.
improvements
221
sin sys.
θ23=0.43
7.8x10w/ 2016errs.
15 POT True
2
True
sin
θ
=0.50
2
23
True sin θ23=0.43
2
True
sin
θ
2
23=0.60
True sin θ =0.50
21

23

2

True sin θ23=0.60

10

3σ C.L.

3σ C.L.

99% C.L.

5

99% C.L.

5

90% C.L.

90% C.L.

0
−200

0
−200
−100

−100
0
0 True δ100(°)

True δCP(°)

CP

100
200

200

hierarchy unknown(a) Assuming the MH is unknown.

15
10

T2K Preliminary
T2K
20x1021 POT w/ eff. stat. &sys. Preliminary
improvements

20

21

POT&w/
2016
sys. errs.
20x1021 POT7.8x10
w/ eff. stat.
sys.
improvements
221
sin θsys.
7.8x10 POTTrue
w/ 2016
errs.
23=0.43
15
2
True
sin
θ
=0.50
2
23
True sin θ23=0.43
2
True
sin
θ
2
23=0.60
True sin θ =0.50
23

2

True sin θ23=0.60
10
3σ C.L.

3σ C.L.

99% C.L.

5

99% C.L.

5

90% C.L.

90% C.L.

0
−200

0
−200
−100

−100

0

0 True δ100(°)

True δCP(°)

CP

100
200

∆ χ2 to exclude sinδCP=0

0

21

20

∆ χ2 to exclude sinδCP=0

5

T2K Preliminary
20x1021 POT w/ eff. stat. T2K& sys.Preliminary
improvements20∆ χ2 to exclude sinδCP=00∆ χ2 to exclude sinδCP=0

T2K-II: PHYSICS POTENTIAL

T2K Preliminary

15

True sin2θ23=0.43
True sin2θ23=0.50

10

200

True sin2θ23=0.60

w/ eff. stat. improvements (no sys. errors)
w/ eff. stat. & sys. improvements

3σ C.L.

99% C.L.

5
90% C.L.

0
0

5

10

15

20

Protons-on-Target (x1021)(b)
Assuminghierarchy
the MH is known
external
input– measured by(b) Assuming the MH is known – measured by
FIG.
Sensitivity to CP
violation aan outside experiment.
(a) Assuming the MH is unknown.
−3 22:
T2K Preliminary
39
×
10
3
an outsidestatistics/POT
experiment.
• Assumes ~50% increase in effectiveHyper-Kamiokande
Accelerator Neutrino Atmospherebeam from J-PARC

SupernovaSun

Neutrinos

Hyper-Kamiokande
Total mass 260 kton

Proton Decay

Fiducial 190 kton

New photo-sensors

Tank filled with purewater 74m (D) x 60m (H)40

CP violation in Hyper-K•

beam ν

Atmospheric&ν&+&beam&ν

Beam
Beam ++Atm
Atm νν

Sunny Seo

Colloquium @ U. Melbourne. 2018.05.15

15

δcp
Uncertainty
δcp
Uncertainty

δcp
δcpUncertainty
Uncertainty

beam ν + Atm. ν

Better sensitivity on massordering and θ23 octant
separation by combiningum@ U. Melbourne.
2018.05.15 νatm.
ν + beam

88

10yr
10yr

77
66

5yr
5yr

55
44

3 3σσ

33
22

1yr
1yr

11
00

0.40.4

0.45
0.45

15

0.5
0.55
0.5
0.55
2 2
sin
θ
sin θ23 23

0.6
0.6

∆ χ22 Wrong Octant Rejection∆ χ Wrong Octant Rejection•∆ χ2 Wrong Hierarchy Rejection∆ χ2 Wrong Hierarchy Rejection

88

10yr
10yr

77
66

5yr
5yr

55
44

1yr
1yr

33σσ

33

22σσ

22
11
00

0.4
0.4

0.45
0.45

0.5
0.5
2 2
sin
θ23
sin
θ23

41
• Enhanced&sensi?vity&by&beam&ν&measurement.&

0.55
0.55

0.6
0.6

+
𝟎
+
𝟎
ProtonDecay
ProtonDecay
DecaySensitivity,
Sensitivity,p →p→Proton𝒆𝒆

Proton→→𝒆+𝒆+𝟎 𝟎is isa favoured
modelof many
GUTs.
Protondecay
decayp pa favoured
modelof many
GUTs.
• Keep looking
for analysis
GUT
withasneutrinos.
Similarin in
SKSK
butbutwithneutrontagging
Similaranalysisaswithneutrontagging(removeeventswitha taggedneutron)thanksto to(removeeventswithataggedneutron)thanks+π0 in Hyper-K• Example:p→e
improved
improvedPMTs.
PMTs. 3σ discovery potential reaching t ~3σ discovery potential reaching t ~35 35
10
yrs.yrs.
Similarsensitivity
to PTEP,
34
10
Similarsensitivity
to PTEP,34
tproton=1.4×10
years
(SK
90%
CL
limit)
tproton =1.4×10 years (SK 90% CL limit) thanks to the neutron tagging.
thanks to the neutron tagging.
Free
ProtonEnhancedFree
ProtonEnhanced

50kton0.52Mton=520kt

0 < Ptot < 100 MeV/csignal
0 < Ptot < 100 MeV/csignalatm. bkgd
atm. bkgd(380ktoBoundProton Enhanced
BoundProton Enhanced
100 < Ptot < 250 MeV/c
100 < Ptot < 250 MeV/cx10(x20 fiducial mass)

arX
arX
PT

The Hyper-Kamiokande Experiment

LAr discovery potential computed using
LAr discovery
potential
computed using
numbers
from DUNE
CDR 2015.
42 numbers from DUNE CDR 2015.

22

22

Exploration of Particle Physics and Cosmology
with Neutrinos

43

Exploration of Particle Physics and Cosmology with Neutrinos

Experimental group of T2K

Review Committee

44Summary•

A hint of CP violation in neutrinos.
•

95% CL (2 σ) indication from T2K today•δCP ~ -π/2 (CP violation) is preferable in the global ﬁt•

T2K-II is proposed to reach 3σ discovery sensitivity with
1.3 MW beam.

•

Hyper-K will be realized and will study neutrino CP violation
with >5σ discovery.

Stay Tuned!
45

Backup46

Systematic Errors% Errors on Predicted Event Rates (Osc. Para. A)
1R μ-like•

1R e-like

Error Source

FHC

RHC

FHC

RHC

FHC CC1π FHC/RHCSK Detector

2.40

2.01

2.83

3.79

13.16

1.47

SK FSI+SI+PN

2.20

1.98

3.02

2.31

11.44

1.58

ND280 const. ﬂux & xsec

2.88

2.68

3.02

2.86

3.82

2.31

Eb

2.43

1.73

7.26

3.66

3.01

3.74

σ(νe)/σ(νμ), σ(νe)/σ(νμ)

0.00

0.00

2.63

1.46

2.62

3.03

NC1γ

0.00

0.00

1.07

2.58

0.33

1.49

NC Other

0.25

0.25

0.14

0.33

0.99

0.18

Total Systematic Error

4.91

4.28

9.60

7.87

18.65

5.93

Total error is in the 4-10% range. ~6% error on the relative
rate for neutrino mode and antineutrino mode samples47

as a function of parameters

NOvA and T2K
Results

Combinedmbined Appearance/Disappearance Results

NOvA→ ne and ne appearance probabilities
areNOvA Preliminary
cted in the
same
NOvA
FD way2
Total events - antineutrino beamCPesin2θ23

sin 2θ13=0.082

20

0.5

appearance, minimize

0.4

~30%)
20

0.3

UO
=
π/2
→
maximizenappearance,
2 minimizeCPesin θ =0.59

3σBest Fit

NH

1σ

2σ

3σ

Best Fit

IH

23

LO
2
sin θ23=0.46

0.6

IH

ormal hierarchy → same as δCP=-π/2 but
10NH
aller effect in T2K (~10%)Δm232=+2.50×10-3eV2

0.5

0.4

verted 5hierarchy→same
as δCP=π/2 but
δCP= 0δCP=
π/2πδ(~10%)
aller effectδin
CP=T2K
CP= 3π/2
30

2σ

0.7

Δm232=−2.55×10-3eV220

1σsin2θ23~30%)15

For
T2K:
T2K

0.7

0.6

3

25 9.48×10 POT (ν)
6.91maximize
×1020 POT (ν) n= -π/2 →NOvA Preliminary

40

50

60

70

0.3
0

π
2

π

δCP

3π
2

2π

80

Total events - neutrino beam

(Errors shown for the case of δCP = −π/2 and sin2θ23 = 0.5, NO, w/reactor constraint)

Prefer• normal hierarchy by 1.8

It is a very interesting situation, and we need
TMEX:
September
2018
V. Paolone, University of Pittsburgh
Preferupper21,octantExcludemore= ⇡/2 data.
in the IH at > 3
Weakly preferaround ⇡/2 in NH

48

24

Neutrino Oscillation
θ12 = 34.4° ± 1.3°
θ 23 = 45° ± 8° (90%CL)
θ13 ≤ 12° (90%CL)! νe $! ν1 $# ν & =U# ν &PMNS# ν2 &# µ &" 3 %" ντ %

O
R~2.4x10 eV-3§ 0.8 0.55 < 0.21·¨¸
U MNS ≈ ¨ − 0.4 0.6
0.7 ¸
¨ 0.4
¸
0
.
6
0
.
7
©
¹

~7.6x10-5eV22~2.4x10-3eV2~7.6x10-5eV2

δ=?

sij = sin θ ij , cij = cosθ ij§ 0.97 0.23 0.004 ·−iδ ¸% ""U c≈ ¨ 0.23 0 0.97%
s13e0.04 ¸ c12
0 '$ CKM 13¨'$¸¨ 0.008 0.04
s23 '$
0©
1
0 1 ¹'$ −s12'$7 −s eiδ δ∼60
'$
0 oc

" 1 0
$
U PMNS = $ 0 c23$ 0 −s c
23
23 & #
#

13

13

&#

0

s12 0 %'
c12 0 '
0 1 '&

Atm. ν、Acc. ν Acc.ν、Rea. ν、（Atm.ν）Rea. ν、Solar ν" 0.8$
U PMNS ~ $ −0.4
$ 0.4
#

0.55
0.6
0.6

0.15
0.7
0.7

δ〜unknown

%
'
'
'
&

! 0.97#
UCKM ~ # 0.23
# 0.008
"

49

0.23
0.97
0.04

0.004
0.04
~1

δ=60°

$
&
&
&
%

Super Kamiokande“far” detector (FD)50

J-PARC

Kamioka

Tokai
295 kmJ-PARC~500 collaborators fro
58 institutions, 12 natio

atmospheric neutrino oscillation
Nucl.Phys. B669, 255(2003) Nucl. Phys. B680, 479(2004)

Solar term
Interference term (δCP)
θ13 resonance termr: µ/e flux ratio (~2 at low energy)!
!
P2 =|Aeµ|2km: 2ν transition probability νe  νµτ in matter!
~100
R2 = Re(A*eeAeµ)!
I2 = Im(A*eeAeµ)!
P(QPoQ) 2ν system!
Aee : survival amplitudeof PtheAeµ : transition amplitude of the 2ν system!

Pure oscillation probabilities

P(QPoQe)νe appearance (and νμ disappearance) is
expected with the matter effect in the Earth.
- effect for neutrinos in the case of normal
mass ordering- effect for anti-neutrinos in the inverted
mass ordering~10,000 km

51“Sub-GeV”“Multi-GeV”

[mrad][events/1e14 POT]

T2K Beam monitoring
1.8
1.6
1.4
1.2
1
0.8 Event rate
0.6
0.4
0.5

Horn250kA
Horn205kA
Horn-250kA

Horizontal beam direction

INGRID
MUMON

Vertical beam direction

INGRID
MUMON

Day

0

[mrad]

−0.5
−1
0.5
0
−0.5

T2K Run5

T2K Run6

T2K Run7

T2K Run8

Oct.2014-June.2015

Feb.2016-May.2016

Oct.2016-Apr.2017

T2K Run1

T2K Run2

T2K Run3

T2K Run4

May.2014

Jan.2010-Jun.2010

Nov.2010-Mar.2011

Mar.2012-Jun.2012

Oct.2012-May.2013-Jun.2014

−1
52

Day

Expansion of the Fiducial Volume
old selection

New
selection

Sample
CCQE 1-Ring e-like FHC

Towall Cut
170 cmWall Cut
80 cm

CCQE 1-Ring µ-like FHC

250 cm50 cm

CC1π 1-Ring e-like FHC

270 cm

50 cm

CCQE 1-Ring e-like RHC
CCQE 1-Ring µ-like RHC

170 cm250 cm

80 cm
50 cm

53

Data / Sim.

Events/(100 MeV/c)

Fitting ND280 Data
ν -mode2500

Data
ν CCQE

2000

ν CC 2p-2h

1500

ν CC Res 1π
ν CC Coh 1π1000ν CC Otherν NC modes500

ν modes

0
1.2
1.1
1.0
0.9
0.8

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Reconstructed muon momentum (MeV/c)•

Example ﬁtted FGD2 (water) CC-0π muon momentum•

The ﬁt reproduces the data54well with a p-value of 0.47

IO

15

NuFIT 3.2 (2018)

NO

Minos
NOvA
T2K
LBL-comb

Dc

2

10

5

0
15
Rea + Minos
Rea + NOvA
Rea + T2K
Rea + LBL-comb

Dc

2

10

5

0

0

90

180

dCP

270

360 0
55

90

180

dCP

270

360

2
sin θ23
Data Fit•

Fit the normal and inverted
hierarchies separately•

Results with the reactor
constraint on sin22θ13•

Constraint on sin2θ23 is slightly
stronger than the sensitivity

56

Sensitivityθ23 octant and mass hierarchy•

Bayesian analysis: natural way to infer data preference for θ23 octant or
mass hierarchy•

Assume equal prior probability for both octant and hierarchy hypotheses•

Fraction of steps from Markov Chain in each octant/hierarchy isposterior probability for the octant/hierarchy hypothesis•

T2K data prefers the normal hierarchy and upper octant

Posterior probabilities (with reactor constraint)sin2θ23 < 0.5

sin2θ23 > 0.5

Sum

NH ( Δm232 > 0 )

0.204

0.684

0.888

IH ( Δm232 < 0 )

0.023

0.089

0.112

Sum

0.227

0.773

57