Hyper-Kamiokande project
Masato Shiozawa

Kamioka Observatory, Institute for Cosmic Ray Research, U of Tokyo, andKamioka Satellite, Institute for the Mathematics and Physics of the Universe, U of Tokyo

Kashiwa, March-29-2012

1

Conditions for measuring CP δtt(! e, ! µ , ! " ) = U!MNS(!1, ! 2 , ! 3 )
i

2
2
(m
"
m
j
i )L
*
*
2
P(! " ! ! # ) = $"# " 4# Re(U"iU #iU"iU # j )sin
4E!
j>i

ν, anti-ν

2
2
(m
"
m
j
i )L
*
*
! 2# Im(U!iU "iU!iU " j )sin
2E#j>i

CPV term ! sin ! 12 " sin ! 13 " sin ! 23 " sin " " #m122✓sinθ23~1/√2✓sinθ12~0.5, Δm212~7.6×10-5eV2✓sinθ13~O(0.1)

1998 atm-ν, accelerator-ν2001 solar-ν(LMA), reactor-ν2011 ~2.5σ(T2K), 2012 >5σ(Daya Bay), others

Nature gives us an opportunity of leptonic CPV measurement.
→Need larger detector.

Hyper-K WG,
arXiv:1109.3262 [hep-ex]

Letter of Intent:
The Hyper-Kamiokande Experiment— Detector Design and Physics Potential —K. Abe,12, 14 T. Abe,10 H. Aihara,10, 14 Y. Fukuda,5 Y. Hayato,12, 14 K. Huang,4A. K. Ichikawa,4 M. Ikeda,4 K. Inoue,8, 14 H. Ishino,7 Y. Itow,6 T. Kajita,13, 14 J. Kameda,12, 143262v1 [hep-ex] 15 Sep 2011

Y. Kishimoto,12, 14 M. Koga,8, 14 Y. Koshio,12, 14 K. P. Lee,13 A. Minamino,4 M. Miura,12, 14
S. Moriyama,12, 14 M. Nakahata,12, 14 K. Nakamura,2, 14 T. Nakaya,4, 14 S. Nakayama,12, 14
K. Nishijima,9 Y. Nishimura,12 Y. Obayashi,12, 14 K. Okumura,13 M. Sakuda,7 H. Sekiya,12, 14
M. Shiozawa,12, 14, ∗ A. T. Suzuki,3 Y. Suzuki,12, 14 A. Takeda,12, 14 Y. Takeuchi,3, 14
H. K. M. Tanaka,11 S. Tasaka,1 T. Tomura,12 M. R. Vagins,14 J. Wang,10 and M. Yokoyama10, 14(Hyper-Kamiokande working group)
1 Gifu University, Department of Physics, Gifu, Gifu 501-1193, Japan
2 High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, Japan
3 Kobe University, Department of Physics, Kobe, Hyogo 657-8501, Japan
4 Kyoto University, Department of Physics, Kyoto, Kyoto 606-8502, Japan
5 Miyagi University of Education, Department of Physics, Sendai, Miyagi 980-0845, Japan3

Hyper-K WG,
arXiv:1109.3262 [hep-ex]

Multi-purpose detector, Hyper-K
Supernova• Total (fiducial) volume is 1 (0.56) million ton– 25 × Super-K• Explore full picture of neutrino oscillation
parameters.
– Discovery of leptonic CP violation (Dirac δ)– ν mass hierarchy determination(Δm232>0 or <0)– θ23 octant determination (θ23<π/4 or >π/4)

Sun• Extend nucleon decay search sensitivity– τproton=1034~1035 years• Neutrinos from astrophysical objects– 200 ν’s / day from Sun– 250,000 (50) ν’s from Supernova @Galacticcenter (Andromeda)– 830 ν’s / 10 years Supernova relic ν– WIMP ν, solar flare ν, etc

accelerator

ProtonDecays4ν physics targets of Hyper-K
Given sin2θ13~a few %Daya Bay: sin22θ13 = 0.092 ± 0.016(stat) ± 0.005(syst))‣ Leptonic CP violation, Dirac phase δ
2 >0 or Δm2 <0ν
masshierarchy,
Δm
32
32
‣
‣ θ23 octant, θ23<π/4 or θ23>π/4
Proposal to explore full picture of neutrino
oscillation parameters.

6

Hyper-Kamiokande candidate site
✦ 8km south from Super-K✦ same T2K beam off-axis angle (2.5 degree)✦ same baseline length (295km)✦ 2.6km horizontal drive from entrance✦ under the peak of Nijuugo-yama✦ 648m of rock or 1,750 m.w.e. overburden✦ 13,000 m3/day or 1megaton/80days natural
water

MozumiMineSuper-K

~10km
~8km

N

Tochibora
Mine
Hyper-K

N

1,156m a.s.l.
Candidatesite

0M=845m a.s.l.
overburden!
648m

Hyper-K
Mine
Entrance

200m

508m a.s.l.

7-300M
-370M
-430MCavern excavation

R1
60
00

R3
10
00

5ベンチ
6ベンチ

⑫

7ベンチ

⑬

8ベンチ
9ベンチ

⑭

24661
50000

例2ベンチ
4m＠3ｍ
円周方向 4mピッチ
奥行方向 3mピッチ

側壁部ベンチカット

3ベンチ

600ｋN（L=10ｍ）
1.5m＠3ｍ
4ベンチ

⑨
⑩
⑪

5000 5000 5000
5000 12000
5000
5000 5000 5000
25000
31000
56000
56000

00
30
R3
1ベンチ

⑧

R3
10
00

5ベンチ

600ｋN（L=10ｍ）
1.5m＠3ｍ

6ベンチ⑫

600ｋN（L=10ｍ）
3m＠3ｍ

⑬

600ｋN（L=10ｍ）
8ベンチ
4.5m＠3ｍ

7ベンチ

3m ⑭

24661
50000

9ベンチ

3m

Angle of Internal Friction＝45°
Cohesion＝0.1N/mm2
600ｋN（L=7ｍ）
4.5m＠3ｍ

Stage

800ｋN（L=7ｍ）
3m＠3ｍ

600ｋN（L=10ｍ）
4.5m＠4.5ｍ

(Section G：3m of Max Loosened Zone)

5793

ベンチ(1)
ベンチ(2)

250000
50000

50000

5793
50000

50000

50000
7000

2500

7000
2500

20000

4ベンチ

観測坑道

斜路10%

EL533.000

1段目アプローチ

EL528.000

２段目アプローチ坑道

ベンチ(3)

EL513.000

ベンチ(4)

15000

3ベンチ

⑨

14000

⑧

1段目アプローチ坑道

12000

2ベンチ

56000

⑦

⑤

9@5000=45000

00
30
R3
1ベンチ

⑪

⑤

EL540.000

4000

③

⑥

④

③

⑥

EL483.000

50000

5000 5000 5000
5000 12000
5000
5000 5000 5000
25000
31000
56000
56000

⑤

②

⑩

EL483.000

50000

①
③

②

側面図

4000

2500
2500 7000

側壁部ベンチカット

アーチ部掘削

11000

④

⑦

断面図

EL539.000

①
③
⑤

4000

アーチ部掘削2500
2500 7000•& costing• schedulingongoinggeological survey, in-situ
rock stress tests

11000

EL539.000

R1
60
00

断面図

斜路10%

ベンチ(5)
ベンチ(6)
ベンチ(7)
ベンチ(8)
ベンチ(9)

３段目アプローチ坑道
EL498.000

４段目アプローチ坑道

斜路10%
EL484.000

27

Tank Design• liner• PMT support structure

5 compartments × 2

More on developments• sensors– 20 inch Hybrid PD– New 20inch PMT• proof test by 8inch HPD
under preparation• water-proof system for DAQ
electronics• water purification system,
water quality control• design optimization for lower
cost, shorter construction
period10

Construction start
JFY2012

2013

2014

2015

Schedule
2016

2017

2018

2019

2020

2021

2022

2023

2024

-4 -3 -2 -1 1

2

3

4

5

6

7

8

9

access tunnels, waste rock tunnels
cavity excavation
concrete, liner
PMT support, PMT installation
photo-sensor R&D
preparation for glass valve, PMT production
PMT production

water filling
Operation
assuming budget being approved from JPY2016

x25 Larger ν Target~0.6GeV !µ"295km
Quest for CP Violation
higher intensity ν byin lepton sector
upgraded J-PARCνμ→νe probability
Normal hierarchy
0.1

neutrino

0.1

anti-neutrino

sin22e13=0.1
b= 0b= 1/2/b= /b= -1/2/

0.06
0.04
0.02
0

0

0.08

P(i+Aie)P(i+Aie)0.08

sin22e13=0.1
b= 0b= 1/2/b= /b= -1/2/

0.06
0.04
0.02

1
Ei (GeV)

2

0

0

1
Ei (GeV)‣ CPV test by comparing P(νμ→νe) and P(ν−μ→ν−e)‣ sensitive to exotic CPV (non MNS matrix origin)2

Selected νe CC candidates
νe CC candidates

sin22θ13=0.1, δ=0
500
400
300

S mode 0.75MW×3yrs
Total

300

BG all200

200

BG fromSR

1

2

ESrec (GeV)νμ→νeCC: 3,606 ev−μCC : 35
νμ+ν
−eCC :880
νe+ν
NC
:649

νe signal efficiency
64%

Total
SRqSe + BG
BG SeSeSRSR
BG from SeSRSR
BG fromSR+ SR
BG fromSR

100

100
0
0

S mode 0.75MW×7yrs

001

ESrec (GeV)νμ→νeCC: 2,339 ev−μCC : 23
νμ+ν
−eCC :878
νe+ν
NC
:678

remaining BG
νμ+antiνμCC <0.1%, NCπ0 <5%(0.1<Erecν < 1.25 GeV)

2

Expected νe CC candidates

Total BG
SRSR BG

200

0

150

400

δ=0
δ=1/2πδ=πδ=3/2π40001ESrec (GeV)0δ=1/2πδ=πδ=3/2π

-100
-1500

1

ESrec (GeV)

100
00

Events/50MeV

50

-50

200

100

stat. error only

S modeδ=0
δ=1/2πδ=πδ=3/2π

300

2

100

Events/50MeV

diff. from
δ=0 case

S modeEvents/50MeV

600

Events/50MeV

νe candidates

sin22θ13=0.1

Total BG
SRSR BG

1
rec
ES (GeV)stat. error only50
0

δ=1/2πδ=πδ=3/2π-5022-100 01
rec
ES (GeV)

Numbers and shape for CP measurement

2

Contours
Normal mass hierarchy (known)

1

T2K90%CL

7.5MW・years

DayaBay1σCL

I@UB

1X
2X
3X
0

Normal Hierarchy

-1

0

0.05

0.1

0.15

sin22V13

Good sensitivity in whole θ13 allowed region!

δ resolution
Normal mass hierarchy (known)

60

sin22θ13=0.1

1X error of I (degree)

I=90o

3.75 MW·yrs(750kW×5yrs)

40

20

0

0

1

I=0o
sin2ѡ13=0.1

7.5 MW·yrs(750kW×10yrs/
1.5MW×5yrs)

2
3
4
5
6
7
8
Integrated beam power (MW∙year)‣δ precision < 20° (δ=90°)< 10° (δ= 0°)‣modest dependence on θ13 value

910

mass hierarchy determination
T2K90%CL

discrimination power of mass hierarchy

DayaBay1σ

I@UB

1

0

1X
2X
3X
-1

0

0.05

0.1
sin22V13

0.15

Chance to determine MH by HK-JPARC experiment !

Fraction of δ (%) for CPV discovery
Fraction of δ in % for which expected CPV (sinδ≠0) significance is >3σ100

sin22V13= 0.1 / 0.03

3.75 MW·yrs(750kW×5yrs)

80)UDFWLRQRIѝ 

0+NQRZQ
0+XQNQRZQ

sin22θ13=0.1
Mass hierarchy
(MW×
yrs)

60
40

3.75 69% 42%

7.5 MW·yrs(750kW×10yrs/
1.5MW×5yrs)

20

known unknown

7.5

74% 54%

0
0

1

2

3

4

5

6

7

8

9

10

,QWHJUDWHGEHDPSRZHU 0:t107V• Effect of unknown mass hierarchy is limited• Input from atm ν and other experiments also expected for MH

Atmospheric νe fluxr

NuclPhysB669,255(2003)
NuclPhysB680,479(2004)

Oscillated νe flux
Non-oscillation: µ/e flux ratio (~2 at low energy)!
!
2
P2 = |Aeµ| : 2! transition probability !e ! !µ" in matter!
R2 = Re(A*eeAeµ)!
I2 = Im(A*eeAeµ)!
Aee : survival amplitude of the 2! system!
Aeµ : transition amplitude of the 2! system!

Solar term
c e 2 $ 23
an
n
o
sin
res m (r "$ 13 2 $ 13
in
#s

)
!1

Interference term (!C"13 resonance termνe appearance is expected due to Earth’s matter
potential- happens in ν in the case of normal mass hierarchy- in anti-ν in inverted mass hierarchy

Large θ13 value gives us a good chance to discriminate
mass hierarchy.

Mass hierarchy discrimination powersin2 e23 = 0.4
sin2 e23 = 0.4
sin2 e23 = 0.4
sin2 e23 = 0.5
sin2 e23 = 0.5
sin2 e23 = 0.5
sin2 e23 = 0.6
sin2 e23 = 0.6
sin2 e23 = 0.6

45
40

IH

NH

6 r2 (r2 -r2 )3530

sin2 2e13 = 0.04
sin2 2e13 = 0.08
sin2 2e13 = 0.16
sin2 2e13 = 0.04
sin2 2e13 = 0.08
sin2 2e13 = 0.16
sin2 2e13 = 0.04
sin2 2e13 = 0.08
sin2 2e13 = 0.16

50
45

2θ

sin

23

35
30

Normal mass hierarchy

25 HK fiducial mass: 560 kTon
2θ

20

sin

15

0.5

>3σ

=
23

25
20

10

5

5

sin2θ23=0.4
1

DayaBay1σ

15

10 3 m0

Normal mass hierarchy Hyper-K 10 years

40

.6
0
=

6 r2

50

2

3

4

5

6

7

8

9

10

0

Hyper-K years

0.06 0.08 0.1 2 0.12 0.14 0.16 0.18
sin 2e13‣expect to discriminate normal from inverted hierarchy w/ 3σ significance by~5years data.
‣Large θ13 (and θ23) values are encouraging.

θ23 octant
sin22θ23=0.96↓
sin2θ23=0.4 or 0.6
Normal mass hierarchy
Hyper-K 10 years
90% C.L.

No fake solutions

0.25
0.2
sin2 2e13

True

0.3

Normal mass hierarchy
Hyper-K 10 years
90% C.L.

0.25
0.2
sin2 2e13

0.3

sin22θ23=0.99↓
sin2θ23=0.45 or 0.55

0.15

0.15

DayaBay1σ

0.1

0.1

0.05

0.05

0

0

0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7
sin2 e23

0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7
sin2 e23

If sin22θ23<0.99, θ23 octant can be determined.

23p→e++π0 searches

Super-K data are well reproduced by BG MC.
SK1~4

800
600
400
200

10

3

10

SK1~4

10
Signal Box

10

1

0

200

400

600

800

1000 1200
2

Invariant proton mass (MeV/c )PRD77:032003,2008

10

-1

0

200

400

600

800

1000 1200
2

Total invariant mass (MeV/c )SK1~4

Super-Kamiokande
219.7 ktyr exposure

DST
2,3ringPID0/decay-e1

10Signal Box

2

10

2

(events/ktyr)

10
Number of events

Total momentum (MeV/c)

1000

0

Super-K cut!
! 2 or 3 Cherenkov rings"! All rings are showering"! 85 < M!0 < 185MeV/c2 (3-ring)"! No decay electron"! 800 < Mproton < 1050 MeV/c2"
Ptotal < 250 MeV/c "

10

-1

Mtot
Atm. i MC
Data

Ptot

-2

-3

A

B

C

D

E

Selection criteria- detection efficiency = 45%- atmospheric ν BG = 2.1±0.3(stat.)±0.8(syst.) (Mton×years)-1- τproton/Br > 1.3 ×1034 years @ 90%CL‣ BG measurement by accelerator ν (K2K)‣BG=1.63+0.42/-0.33(stat.)+0.45/-0.51(syst.) (Mt×yrs)-1 (Eν<3GeV)‣Consistent w/ simulation 1.8±0.3(stat.)

Quality of next generation search is guaranteed.
24

Search for various decay modes- many models predicts branching ratio of p→e+η, e+ρ, e+ω are 10~20%- Flipped SU(5) (Ellis) predicts Br(p→e+π0)~Br(p→μ+π0)- (B-L) violated mode, e.g. |ΔB|=2.
Soudan Frejus Kamiokande IMB
p A e+ /0

Super-K
1

2 3

4

Hyper-K Hyper-K sensitivitiesn A e+ /-‣p→e++π0‣τproton/Br > 1.3 ×1035 years @90%CL‣5.6Mton×years (10 Hyper-K years)

p A ++ /0
n A ++ /p A i /+n A i /0
p A e+ d
p A ++ dn A id‣p,n→(e+,μ+)+(π,ρ,ω,η)‣O(1034~35)years

p A e+ l0
n A e+ lp A ++ l0
n A ++ l-‣SUSY favored p→ν+K+‣2.5×1034 years

p A i l+n A i l0p A e+ t
p A ++ t
n A itp A e+ K 0
n A e+ K n A e- K +p A ++ K 0
n A ++ K -‣K0 modes, νπ0, νπ+ possible

p A iK+n A iK0
p A e+ K*(892)0
p A i K*(892)+
n A i K*(892)0

32

10

10

33

o/B (years)

35

34

10

25

10

‣Other various decay modes.
‣(B-L) violated modes‣radiative decays p→e+γ, μ+γ‣neutron-antineutron振動 (|ΔB|=2)‣di-nucleon decays (|ΔB|=2)‣pp→XX..., nn→XX...

Summary- Hyper-Kamiokande will cover rich physics topics.
- discovery reach for leptonic CP violation.
- good chance to discriminate hierarchy and θ23 octant.
- ~10 times better sensitivity for nucleon decays.
- various astrophysical objects.
- Effect of large sin22θ13 (~0.1)-JPARC-HK-small effect on CPV test if mass hierarchy is known.
-(δ, sign(Δm223)) degeneracy may happen.
-Chance to determine the mass hierarchy.
-Atmospheric ν-Good chance to determine the mass hierarchy andθ23 octant