# Presentation: 864515

## ・ Introduction

- Takaaki Kajita, ICRR, U. Tokyo

- ・ Introduction
- ・ JHF-Kamioka neutrino project -overview-
- ・ Physics in phase-I
- ・ Phase-II
- ・ Summary

- Outline

- The JHF-Kamioka neutrino project

## Introduction

## SK atmospheric neutrino data

- Whole SK-1 data have been analyzed.

- 1489day FC+PC data  +  1678day upward going muon data

-      1-ring e-like     1-ring μ-like   multi-ring μ-like    up-going μ

- Up-going    Down-going

- No osc.

- Osc.

- stopping

- Through going

- < 1.3GeV

- > 1.3GeV

## Oscillation parameters

- Kamiokande

- Soudan-2

- MACRO

- SK

- νμ→ντ 90%C.L.

- Limit on θ13

## K2K

**E******

**E******

- 250km

## K2K data and oscillation 

**Best fit point (sin****2****2******** , ********m****2****)**
**=**** ****(1.0,   2.8x10****-3****eV****2****) **

_**N**_**SK**_** (# of event)**__** **_
** ****56**** events observed**
** ****80.1+6.2/-5.4**** ev. expt’d**
**null oscillation prob. 1.3%**

- +

- Data: 1999 – July 2001

- Consistent with SK atm.

## Next:

- MINOS (end of 2004):                    Detail study of oscillations.

- Next2:

- JHF-Kamioka neutrino project

- CNGS (OPERA, ICARUS) (2006) : τ appearance.

## JHF-Kamioka neutrino project 

- -overview-

## Main goals 

- ★Precise determination of neutrino oscillation parameters.
-            Accuracy: sin22θ  ・・・・・・ 1%
-                         Δm2 ・・・・・・・・・・ a few %
- ★Discovery and measurement of non-zero θ
-             sin22θ   ・・・・・・  > 0.01

- Main physics goals in JHF-I neutrino exp.

- 23

- 13

- 13

- ★Discovery and measurement of non-zero CP phase

- Main physics goal in JHF-II

## JHF-Kamioka neutrino project –overview-

**< 1 GeV ν****μ****  beam **

**0.75 MW  50 GeV PS**

**50 kton**
**Water Cherenkov**** **

**~****1Mt “Hyper Kamiokande”**

**4MW 50GeV PS**

- Future

- Future

## Present collaboration

- Canada USA

- UK     Poland    France   Switzerland    Italy     Spain

- Russia

- Korea Japan  China

## J-PARC(JHF) Facility

**Construction**
**2001****~****2006 (approved)**

- (0.75MW)

**Near detectors (280m,2km)**

-   beam-line + detectors
-   budget request will be submitted soon.

|  | JHF | NuMI
(FNAL) | K2K |
| --- | --- | --- | --- |
| E(GeV) | 50 | 120 | 12 |
| Int.(1012ppp) | 330 | 40 | 6 |
| Rate(Hz) | 0.275 | 0.53 | 0.45 |
| Power(MW) | 0.75 | 0.41 | 0.0052 |

**To SK**

## Primary proton beamline –Overview-

**Preparation section**
- Normal conducting

**Arc    R=105m**
**  **Super conducting
- Dipole + Quadrapole combined function magnet

**Final Focusing Section**
- Normal conducting

- Single turn fast extraction
- 8 bunches/~5s
- 3.3x1014proton/pulse
- 3.64 sec cycle
- 1yr≡1021proton on target(POT)

- 50GeV PS

## Slide 14

## J-PARC construction 

- J-PARC construction

## J-PARC LINAC construction (Apr.03)

## The beam: Off axis beam

- (ref.: BNL-E889 Proposal)

**E****π**** vs. E****ν**

- Eπ

- Eν

- 0.0 ゚

- 1.0 ゚

- 1.5 ゚

- 2.0 ゚

- 3.0 ゚

- 5.0 ゚

- 2.5±0.5 ゚

- Max. osc. energy for 3×10-3eV2

**OA3°**

**OA2°**

**OA1°**

- 2200 CC νμ / year

- 800 CC νμ / year

## Target and horns (preliminary design)

- 1.5m       0.5m       2.0m                        3.5m                            2.5m

- 320kA

- 320kA

- 320kA

- Target: Graphite (φ=25-30mm) w/ water cooling

- Horn

- Temperature rise due to radiation

- Need much more detailed studies

## Decay tunnel design

- 130 meters

## Decay pipe cooling and heat simulation

- Non-static heat simulation
- 0.5yr@4MW, 0.5yr no beam
- Upto 30yrs
- Max @ 29.5yr

- Iron part
- Max 54o

- Concrete
- Max 121o

## Detector system 

**p**

****

****

**140m**

**0m**

**280m**

**2 km**

**295 km**

- 15.2m

- Total mass : 1000ton

- Fid. Mass : 100ton

-  ν beam

- Fine grained scintillater detector

- 5m

- 8m

- 8m

- Water Cherenkov detector

- Muon detector

- Near detector @2km (@50m underground)

- μ

- ν

- ν

- SK

## Event rate          &        Far/near ratio

- Distance from target (km)

- 6 /100ton/spill @280m

- 0.1 /100ton/spill @2km

- Water Cherenkov : Impossible @280m  (Total mass > 100 tons)

- (φfar / φnear)×(Lfar / Lnear)

- 2

- 2

- 1

- 1

- 0

- 0

- @280m

- @2km

- Not a good place....

- OK !

- 0

- 1

- 2

- 3

- Eν(GeV)

## Near detector @1.84km 

- Candidate site
- (Owner: Tokai-village (local government))

## Physics in Phase-I

## Reconstruction of Eν

- JHF Eν

- Eμ,  θμ

- Eν

- Non-QE

- Quasi-elastic

- Super-K w/ JHF beam

- For single Ch ring events:

## Quasi-elastic and other interactions

- High Eν non-quasi-elastic interactions cause problems.
- Minimize the high energy (above the max. osc. energy) neutrino flux.

## Single ring (muon-like)  in Super-K

- Data sample: SK Monte Carlo, Fully-contained single-ring, muon-like events.

- Event fraction

- Typical JHF neutrino energy

- Important to run the experiment with low energy beam.

- π

- π

## Measurement of sin 2θ23

- 1 %

- (OA 2deg)

-  2               4 ×10-3eV2

- OA 2deg

- OA 3deg

## Δm2 dependence of the sensitivity

- Off-axis angle should be adjusted to about 0.1 deg.

- Δm2 dependence of the sensitivity

## θ13

- Present status:

- BG (NC π0 ....)

- Signal for non-zero θ13 in  JHF-SK (νμ→νe)

- Allowed

## νe beam contamination

- OAB (2degree)

- νe/νμ ratio=0.2% at the spectrum peak.

**K-decay**

******-decay**

********

******e**

**0.2%**

## Number of signal events and BG

- m2=3x10-3eV2,
- sin22=0.1

- OAB 2deg., 5yrs

|  | C.C. | N.C. | Beam e | Osc'd e |
| --- | --- | --- | --- | --- |
| Generated | 10713.6 | 4080.3 | 292.1 | 301.6 |
| 1ring e-like | 14.3 | 247.1 | 68.4 | 203.7 |
| red. eff. | 0.1% | 6.1% | 23.4% | 67.5% |
| e/0 sep. | 3.5 | 23.0 | 21.9 | 152.2 |
| red.eff. | 0.03% | 0.6% | 7.5% | 50.4% |
| .4<E<1.2 | 1.8 | 9.3 | 11.1 | 123.2 |
| red.eff. | 0.02% | 0.2% | 3.8% | 40.8% |

## e/π0 separation

- e/π0 separation

- Shower direction w.r.t. beam
- (1) cose: 0 tend to have a forward peak
- Force to find 2nd ring and...
- (2) E(2)/E(1+2): Large for BG
- (3) Likelihood diff. between 1 and 2-ring assumptions
- (4) Invariant mass: Small for e

- BG

- νe

- Select

- (1)

- (2)

- (3)

- (4)

## Measurement of sin22θ13

- Measurement of sin22θ13

- sin22θ13

- Δm2

| sin 2θ13 | νμ(CC+NC) | Bean νe | Osc’d νe | Signal+BG |
| --- | --- | --- | --- | --- |
| 0.1        | 11.1 | 11.1 | 123.2 | 145.5 |
| 0.01 | 11.1 | 11.1 | 12.3 | 34.5 |

- 2

- Expected signal for

- OA 2deg 5yrs

- ×1/20

- CHOOZ limit

- JHF sensitivity

## Phase-II

## JHF Phase-II 

- 106 events

- ★0.77 → 4 MW beam power
- ★~1 Mton detector    (Hyper-Kamiokande)

- CP Violation

## Assumptions

- Solid line: w/ matter
- Dashed line: w/o matter

- (unless otherwise stated)

## Neutrino and anti-neutrino runs

**10****21****pot/yr**
**(1st phase)**

- Important to understand the wrong sign contamination

## Expected CP violation signal(1)

- sin2213=0.1

- m31<0

- m31>0

- 90%C.L. stat only

- 90%C.L. stat+2% syst.

- 3 stat only

- 3 stat+2% syst.

- # of e- events including BG

- # of e+ events including BG

- CP phase

## Expected CP violation signal (2)

- sin2213=0.01

- m31<0

- m31>0

- 90%C.L. stat only

- 90%C.L. stat+2% syst.

- 3 stat only

- 3 stat+2% syst.

- # of e- events including BG

- # of e+ events including BG

- CP phase

## 3σ CP sensitivity 

- 3σ CP sensitivity

**no BG**
**signal stat only**

**(signal+BG) stat only**

**stat+2%syst.**

- stat+5%syst.

- stat+10%syst.

- CHOOZ excluded
- sin2213<0.12@m312~3x10-3eV2

**JHF-I: No indication for sin****2****2θ****13**

**3******** CP sensitivity : |********|>20****o**** for sin****2****2********13****>0.01 with 2% syst.**

- sin22θ13

- sinδ

## Decay Pipe Common for SK/HK

**SK**

**~8 km**

**HK**

- Possible site for Hyper-K

- Common off-axis angle (2-3 degrees) for both Super-K and Hyper-K

- Beam center

## ● Main goals of JHF-Kamioka neutrino project (Phase-II) 

-   ★Precise determination of neutrino oscillation parameters.
-            Accuracy: sin22θ  ・・・・・・ 1%
-                         Δm2 ・・・・・・・・・・ a few %
-   ★Discovery and measurement of non-zero θ13
-             sin22θ   ・・・・・・  > 0.01
- ● Main goals of JHF-Kamioka neutrino project (Phase-II)
-   ★Discovery and measurement of non-zero CP phase
- ● Design works are in progress hoping to start the experiment by (the end of 2007 or) early 2008.

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- Summary