# Presentation: 276599

## Recent Results from Neutrino Experiments and Plans for the Neutrino Super Beam in Japan

**Discovery of ****neutrino oscillations ******** ****finite neutrino masses**** (********2**** and ********3****) (1998 – present)**
**Small as expected**
**Mixing among neutrino flavors expected**
**Quark mixing implies small mixing**

**Y.Totsuka, KEK**
**NSS-2003, 031021**

## Mixing matrix

******e**
********
********

- (

- )

**=  **

******1**
******2**
******3**

- (

- )

**U****e1**
**U********1**
**U********1**

- (

**U****e2**
**U********2**
**U********2**

**U****e3**
**U********3**
**U********3**

- )

| c12c13 | s12c13 | s13e-i |
| --- | --- | --- |
| -s12c23-c12s13s23e-i | c12c23-s12s13s23e-i | c13s23 |
| s12s23-c12s13c23e-i | -c12s23-s12s13c23e-i | c13s23 |

**U ****(****Maki-Nakagawa-Sakata Matrix) =**

**s****ij****=sin********ij****,** **c****ij****=cos********ij****, ********=CP**

**Mixing matrix**

- (

- )

**Free moving states**
**(mass eigenstates)**

**Interacting states**

** ****Discovery of ****large mixing angles****, ********23**** and ********12**

## Atmospheric neutrinos - I

**Atmospheric neutrinos - I**

******e**

**Earth**

**Super-K**

**e****±**

**Expected event rate is uncertain by ~15%**
********** ****: ********e**** = 2 : 1 (low energy) known better than 5%**
**Up-down symmetry for E******** > 1 GeV**

## Super-Kamiokande (1996)

**Super-Kamiokande (1996)**

**1996-**
**50000ton water**
**11146 50cm******** PMT****   (40% photo coverage)**
**1000m underground**
**Min det. energy ~ ****5 MeV**
**Basic reactions**
********** ****+ N ******** ******** + X**
******e**** + N ******** e + X**

## Super-Kamiokande II

**SK-II Cosmic ray muon sample**

**Super-Kamiokande II**

**Accident on Nov 12, 2001**
**Repaired and restarted in Dec, 2002**
**Inner detector with ~5200 20” PMTs**
**Outer detector with 1885 8” PMTs**

## 1489 day FC+PC data  +  1646 day upward going muon data

******2****=170.8/170 d.o.f. at (sin****2****2********23****, ********m****23****2****)=(1.00, 2.0x10****-3****eV****2****)**
******2****=445.2/172 d.o.f. (null oscillation)**

**1489 day FC+PC data  +  1646 day upward going muon data**

## Allowed region of the oscillation parameters

**Allowed region of the oscillation parameters**

**Assuming **************************** oscillation**
**Best fit**
** ********2****min ****= 170.8/170 d.o.f**
**at (sin****2****2********23******** ********m****23****2****) =****    (1.0, 2.0 x 10****-3 ****eV****2****)**
**90% CL allowed region**
**sin****2****2********23********> 0.9**
**1.3x10****-3**** < ********m****23****2 ****<3.0x10****-3**** **** ****(eV****2****)**
**Assuming null oscillation**
** ********2 ****= 445.2/172 d.o.f**

**(complete SK-I dataset)**

- Soudan-2

- MACRO

**Super-K**
**68% CL**
**90% CL**
**99% CL**

## K2K

**250km**

- Long baseline neutrino oscillation experiment

**12 GeV PS at KEK**
**Neutrino beamline**
**<E********> ~ 1.3GeV**
**98% purity**
**Beam monitors and near detector**
**beam direction**
****** ****measurement**
********** ****flux and spectrum**
**Far detector**
********** ****flux and spectrum**

## Best fit 1R spectrum & Nsk

**Best fit point (sin****2****2********23**** , ********m****23****2****)**** ****=**** ****(1.0,   2.8x10****-3****eV****2****)**
**KS test prob.(shape): 79%**
**N****SK****=54 (Obs.=56)**
**Very good agreement in shape & N****SK**** with atmospheric neutrinos**

**Expected w/o oscillation**
**Normalized w/o oscillation**
**Normalized with best fit oscillation**

**Total number of obs. Events: 56****	****	****16 ****(Jan03-Apr03)**
**Expected w/o oscillation:        80.6**** ****+7.3-8.0****	****24 ****+2.3-2.1**

**Notes:**
For the best histogram, best fit values for oscillation parameters and scale parameter are used. Other parameters like spectrum and so on
are set to the initial value (FD fitted center)
The null-oscillation spectrum is MA wiehgted(1.21)w/nQE20%added model w/ FD fitted center values are used.
When calculated the KS probability, for the best fit distribution, SK energy scale bias is not used.

## Comparison with SK atm  observation

**Comparison with SK atm ******** observation**

**K2K(1R******** shape+N****SK****)**

**SK (FC+PC+up********)**** **

- 90%CL

## Solar image

**Solar image**

## SNO: e  e (ES); ed  epp (CC); d  pn, Cl(n,)Cl, (NC)

**Electronics hut**

**Control room**

**1000 ton heavy water ****(12m******** acrylic vessel)**

**9456 of **
**8 inch PMTs**

**INCO’s Creighnton mine**
**Sudbury, ON, Canada**

- 2km

**SNO**

**1700+5300 ton light water**
**(17.8m******** stainless steel support, 34mh x 22m******** barrel-shaped cavity)**

**(6010mwe)**

**photo coverage****	****55% (R<7m)**
** ****cosmic ray muons****	****~70 events/day**
** ****fiducial volume****	****0.7kt (R,5.5m)**
** ****Trigger rate (data)          6~8Hz****                                         (~2MeV threshold)**
** ****Trigger efficiency****	****100%@~3MeV**
** ****From compton e- from ****16****N source (~5 MeV)**
**   ****vertex resolution****	****16cm**
**   ****energy resolution****	****16%**
**   ****angular resolution****	****27°C**
**NaCl in D****2****O**

## Super-K + SNO combined (as of 2002)

******CC ****=**** ********e**
******ES ****=**** ********e ****+0.154**** ************,******
******NC**** ****=**** ********e ****+**** **** ************,******

**SNO ****	********CC**** = 1.7+-0.05+-0.09**
**             ********ES  ****= 2.39         +-0.12**
**           ********NC****  ****= 5.09**
**SK    ****	********ES  ****= 2.32+-0.03**
**Evidence for an active **
**non-********e ****component****!**

- [x106/cm2/s]

**Super-K + SNO combined ****(as of 2002)**

**+0.24**
**- 0.23**

**+0.44  +0.46**
**- 0.43  - 0.43**

**+0.08**
**- 0.07**

## SNO rates and day/night spectra

**SNO rates and day/night spectra**

**and  Super-K zenith spectra**

******e**** ******** ************ oscillation**** **

**-3**

**-4**

**-5**

**-6**

**-7**

**-8**

**-9**

**-10**

**-11**

**log ********m****2**** (eV****2****)**

**-4**

**-3**

**-2**

**-1**

**0**

**1**

**Log tan****2******

## Kam-LAND

**1000m****3**** liquid scintillator**
**3000m****3**** oil+water shield**
**1300 17-inch PMTs + 600 20-inch PMTs**
**Anti-********e**** from reactors (L~170km)**
**Detect e****+**** from ********e**** + p ******** e****+**** + n****   (Eth = 1.8 MeV)**
**Observation started on 22 Jan 2002**

## Kam-LAND result

**145.1 live days, 162 ton year exposure**
**Te > 2.6 MeV, 86.8+-5.6 ev expected**
**56 ev observed with 1 BG estimated**

**Te > 0.9MeV**
**124.8+-7.5 ev expected**
**86 ev observed ****   with 2.9 +-1.1BG estimated**

## KamLAND confirms the LMA solution!

**KamLAND confirms the LMA solution!**

## Nucl-ex/0309004v1 6Sep2003

**FIG. 5: Global neutrino oscillation contours. **
**(a) Solar global: D****2****O day and night spectra, salt CC, NC, ES fluxes, SK, Cl, Ga. The best-fit point is *********m*****2**** = 6.5 × 10****-5****, tan****2********  = 0.40, *****f******B****** *****= 1.04, with 2/d.o.f.=70.2/81. **
**(b) Solar global + KamLAND. The best-fit point is *********m*****2**** = 7.1 × 10****-5****, tan****2********  = 0.41, *****f******B****** *****= 1.02. In both (a) and (b) the ****8****B flux is free and the *****hep *****flux is fixed. *****f******B****** *****= ****8****B flux measured / SSM.**

**SNO**

## What to do next

**What to do next**

**Measure **
******31**** and ********m****31****2**** (~ ********m****23****2****) **
****
******m****12****2****, ********m****23****2****, ********12****, ********23****  precisely**** **

**Quarks:**
**sin****2****2********12**** = 0.188  +-0.007**
**sin****2****2********23**** = 0.0064+-0.0010**

## e , electron appearance

**P(********μ************e********) = 4c****13****2****s****13****2****s****23****2**** sin****2****(********m****31****2****L/4E********)(1 + ****2a(1-2s****13****2****)/********m****31****2****)**
**                  ****+ 8c****13****2****s****12****s****13****s****23****(c****12****c****23**** cos******** – s****12****s****13****s****23****)**
**                     ****×cos(********m****23****2****L/4E********) sin(********m****31****2****L/4E********) sin(********m****21****2****L/4E********)**
**                  ****- 8c****13****2****c****12****c****23****s****12****s****13****s****23**** sin******** **
**                     ****×sin(********m****23****2****L/4E********) sin(********m****31****2****L/4E********) sin(********m****21****2****L/4E********)**
**                  ****+ 4s****12****2****c****13****2****(c****12****2****c****23****2**** + s****12****2****s****23****2****s****13****2**** **
**                      ****- 2c****12****c****23****s****12****s****23****s****13**** cos********) sin****2****(********m****21****2****L/4E********)**
**                  ****-8c****13****2****s****13****2****s****23****2****(1 – 2s****13****2****)(aL/4E********)**
**                     ****×cos(********m****23****2****L/4E********) sin(********m****31****2****L/4E********) ,**
**where a [eV****2****] = 2√2G****F****n****e****E******** = 7.6×10****-5**** ******** [g/cm****3****] E******** [GeV] , ****           ****red**** terms change sign for anti-neutrinos**

## Strategy and Sensitivity Goal (Phase I)

**~ 5 years**
**Precisely measure ********23**** and ********m****23****2****.**
** ********e**** appearance search**
**Sensitivity goals**
******sin****2****2********23**** ~ 0.01**
******m****23****2**** < 1x10****-4 ****eV****2**
**sin****2****2********13**** ~ 0.006 (90% CL)**
**Study neutrino interactions at the near detector**

## T2K (Tokai-to-Kamioka)

**T2K (Tokai-to-Kamioka)**

**J-PARC**

**Hyper-Kamiokande**

## J-PARC

**J-PARC**

**Joint Project by KEK and JAERI**
**3 GeV RCS: spallation-neutron and muon sources**
**Life and material sciences**
**50 GeV MR: slow and fast extracted protons**
**Kaon physics**
**Neutrino physics (long baseline oscillations)**
**LINAC: intense proton source**
**ADS  **

- (180 MeV,

## injection energy      		400 MeV(180 MeV)
extraction energy    		3 GeV
harmonic number       		2
repetition rate      		25 Hz
# of protons / pulse   		0.83 E14
average beam current  		333μA
beam power          		1 MW

**extraction energy****    ****	****	****3 GeV**
**harmonic number****       ****	****	****2**
**repetition rate****      ****	****	****25 Hz**
**# of protons / pulse****   ****	****	****0.83 E14**
**average beam current****  ****	****	****333μA**
**beam power****          ****	****	****1 MW**

**3 GeV RCS**

**Magnetic alloy cavity**

## 50 GeV MR

**Beam energy: ****	****50 GeV (40 ****	****	****	****at phase 1)**
**1 cycle: ****	****	****3.53s**
**8 bunches in 9RF buckets**
**Bunch spacing: ****	****598ns**
**Spill width ~ ****	****	****5********s**
**Bunch length ~ ****	****36ns (±3********)****                              ****	****6ns (1******
**# of protons:****	****3.3×10****14**** ****	****	****	****ppp**
**Beam current: ****	****15********A (slow ****	****	****	****extraction)**
**Rf frequency: ****	****1.68 (inj.) – ****	****	****	****1.73 (ext.) ****	****	****	****MHz**
********** ****flux* at SK =  1.9×10****7**** / cm****2****yr****(1yr = 10****21**** pot:  123 days at .75MW)**

***2.5°Off Axis, 130m decay pipe**

**3.53s**

**1.9s**

**fast**

**Injection****	****	****	****: 0.17s**
**acceleration****	****	****: 1.96s**
**extraction    ****	****	****: 0.7  s**
**current down****	****	****: 0.7  s**
**total:****	****	****	****	****	****: 3.53s**

**slow**

**0.17**

**1.96**

**0.7**

**0.7**

## Neutrino beam line

**600MeV Linac**

**3GeV PS**

**50GeV PS**

- N

**Near Detector (280m)**

**Neutrino Beam Line**

**To Super-Kamiokande**
**(295km away)**

**Neutrino beam line**

**Construction**
**2001****~****2007**

|  | JHF | MINOS | K2K |
| --- | --- | --- | --- |
| E(GeV) | 50 | 120 | 12 |
| Int.(1012ppp) | 330 | 40 | 6 |
| Rate(Hz) | 0.3 | 0.53 | 0.45 |
| Power(MW) | 0.75 | 0.41 | 0.0052 |

**JAERI@Tokai-mura**
**(60km N.E. of KEK)**

**(Approval in Dec.2000)**

## Off Axis Beam 

**WBB with a misaligned beam line from the det. axis**
**High intensity at low energy: 4500 int./22.5kt/yr**
**Contamination ********e****: 0.8%(0.2% @ peak)**

**Decay Kinematics**

**E******** (GeV)**

**E******** (GeV)**

** ****0           0.4        0.8         1.2        1.6        2**

**E******** (GeV)**

**2x10****-3****eV****2****, L = 295km**

## Fast extraction section

**neutrino beamline**

## Arc Section

**Arc Section**

- combined function SC magnets

## Focusing Section

- solid graphite, 30mm in diam, 900mm long

- Target station

## Horn system

**Horn system**

***I*****=~300kA,   three short horns**
**Need to tolerate big heat load from radiation**
**Stress analysis is in progress**

- Carbon target

## Decay Volume

- Side View

- Top view

- 4MW beam can be accepted.

- max.120o
- (half year continuous operation)

- (Temperature is controllable under 100o by intermittent operation)

*Decay Volume*

- Water cooling pipe

- 50o

- 14o

**~3.5deg**

**130m from target**

**To Super-K**

**~1.3deg**

## Near detector at 2km from the target

**Near detector at 2km from the target**

**9.2m**

**16.2m**

**8m**

**4m**

**Total mass : 1077ton**

**Fid. Mass : 100ton**

**Near detector should look like**

**Far detector looks like**

-   **beam**

## Far/near ratio (OA 2deg)

**Far/near ratio (OA 2deg)**

**spectrum**

## Slide 36

## Strategy and Sensitivity Goal (Phase II)

**Intensity upgrade to 4 MW**
**1 Mton far detector, Hyper-Kamiokande**
**Search for CP violation**

## Hyper-Kamiokande (1Mt water)

**Hyper-Kamiokande (1Mt water)**

**Precision neutrino oscillation study**
**Proton decay search **

**R&D (complete in 2 years)**
**Cavity excavation and its stability**
**New light detector: Hybrid Photo-Detector, HPD (50cm********)**

## Sensitivity (3) to CPV (T2K Phase II)

## Conclusions

**Rapid progress in measuring masses and mixing of neutrinos**
******m****23****2**** = 1.3 - 3.0×10****-3**** eV****2****, ****	****sin****2****2********23**** = 0.9 – 1.0**
******m****12****2**** = 6 - 9×10****-5**** eV****2****,       ****	****sin****2****2********12**** = 0.7 – 0.9**
**Their precisions need to be improved**
******23**** and ******** are still unknown**
**J-PARC can produce ************ beam 100 times stronger than K2K (proton beam power; 0.75 MW)**
**Sensitivities; sin****2****2********31**** > 0.006 (90%CL)**
**If ********31**** measured, a further upgrade will be considered**
**proton beam power; 4 MW**
**1 Mton Hyper-K**
**A lot of uncertainties in future**
**Linear collider, budget deficit, etc**

## Supplement

## JSNS23 neutron beam lines

- JSNS23 neutron beam lines