# Presentation: 519486

## T2KS.Mine (University of California, Irvine)for T2K collaboration

**~1GeV ************ beam**
**(~********100 of K2K)**

**J-PARC**
**~0.7****MW 40GeV PS**

**Super-K: 50 kton**
**water Cherenkov**** **

**phase-2:**
**~4 MW **

**phase-2:**
**Hyper-K**** **

- T2KS.Mine (University of California, Irvine)for T2K collaboration

**T**

**K**

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## Physics goals:

Schedule:

- Schedule:

-  discovery of →e appearance
-  precise measurement of  disappearance
-  discovery of CP violation (phase-2)

- J-PARC (~0.7MW 40GeV PS)
- construction: 	2001~2007
- operation:	2008~
- T2K (approved in 2003)
- construction:	2004~2008
- experiment: 	2009 ~

- this talk

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## T2K collaboration

- 12 countries
- ~60 institutions
- ~180 collaborators

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## Accelerator/Beam line status

**Accelerator/Beam line status**

** ******** ****beam line**

**J-PARC**

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## Super-Kamiokande history

- 1996  1997  1998  1999  2000  2001   2002   2003  2004   2005  2006  2007

**SK-I**

**SK-II**

**SK-III**

- accident

- reconstruction

- plastic vessel

**SK-I**

**SK-II**

-       40 %                 photocathode coverage              19 %

-   11,146          number of inner detector PMTs      5,182

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## Narrow intense beam: Off-axis beam

**OA3°**

**OA0°**

**OA2°**

**OA2.5°**

- osc. prob.@
- m2=3x10-3eV2

********** ****flux**

****** ****decay Kinematics**

***p********* (GeV/c)**

- First Application
- (ref.: BNL-E889 Proposal)

- 0o

- 2o

- 2.5o

- 3o

***E********* (GeV)**

*(schematic)*

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

##  interaction @ SK(w/o oscillation)

-  interaction @ SK(w/o oscillation)

- 

- 2.5o off-axis beam (40GeV)
- NEUT
-   int.(22.5kt/1021pot)
-                   ~ 2200()
-  e/ at peak ~0.4%

- e

-  int. @ SK (/50MeV/22.5kt/1021pot)

- neutrino energy (GeV)

- 1021pot~1year

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## 3 flavor oscillation (simplified)

* * disappearance
* *e appearance
-  beam ee oscillation

- P(→e) = sin223 sin2213 sin2(1.27 m132L/E)

- m122=0, m122<<m132=m232
- m232=2.5x10-3eV2,23=/4
- no matter effect
- CP phase =0

*in this analysis*
*unless noted*

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## Selection criteria for e appearance

- Standard SK cuts:
- Further 0 cuts:

- fully contained(FC)
-      in fiducial volume(FV),
-      visible energy>100MeV
- single-ring
- PID(e/)
- no decay-e
- 0.35<Erec<0.85GeV

- cose<0.9
-  M & L cuts of POLfit

- (SK-I detector simulator & reconstruction used)

- signal+BG
- total BG
- e BG

- sin2213=0.1

- events/22.5kt/5x1021pot

- reconstructed energy (GeV)

*(w/o E****rec** cut)*

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## POLfit (0 fitter)

- POLfit (0 fitter)

- 500MeV/c 0 MC
- true P2 = 55.5MeV/c
- rec.M0 =140.4MeV/c2

******1**

******2**

- standard
- fitter

- POLfit

-  input:
-      vertex,1st ring dir.,total Evis
-  output:
-      M, L(0like-elike)

-   force to find 2nd -ring
-   identify and reject
-   asymmetric decay
-   0 BG in 1R-e sample

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## Events vs. selections

|  | CC BG | NC BG | beam e BG | e(CC) signal |
| --- | --- | --- | --- | --- |
| FCFV, Evis>100 | 2215 |  847 |  184 |  243 |
| 1R-e, no decay-e |     12(0.5%) |  156(18%) |    71(39%) |  187(77%) |
| 0.35<Erec<0.85 |    1.8(0.1%) |    47(6%) |    21(11%) |  146(60%) |
| cose<0.9,M<100L<80 | 0.7+9(0.3%) |  |    13(7%) |  103(42%) |

- (events / 22.5kt / 5x1021pot)

- (sin2213=0.1)

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## e sensitivity

- 90%CL
- BG=10%
- 5x1021pot

- CHOOZ
- excluded

- sin2213~0.008
- @2.5x10-3eV2

- sin2213

- m2(eV2)

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## e sensitivity as a function of CP-phase 

- e sensitivity as a function of CP-phase 

- (90%CL, 5x1021pot, BG=10%)

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## e sensitivity vs. exposure(dependence on background uncertainty)

- e sensitivity vs. exposure(dependence on background uncertainty)

- 3

- CL

-  SK itself
-  0 rejection efficiency
-  e/ separation
-  decay-e
-  fiducial volume
-  energy scale
-  etc.
-  0 production
-  beam e

- BG sources:

- sin2213

- exposure (22.5kt •1021pot)

- NDs

- BG=20%
- BG=10%
- BG=5%

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## K2K e search @ SK

- K2K1+K2K2 DATA:
-    FCFV		112 ev
-    Single Ring	             67
-  PID(e/)		    9
-    tight e –ID	    	    8
-    Evis>100 MeV	    7
-    No e from e            5
-    POLfit cut(e/0)         1

- exp’d BG:	            1.63
-  int.                                1.25
-     beam e                            0.38

- (Feldman-Cousins approach)

- CHOOZ
- limit(90%)

- limit

- sensitivity

- expected BG: 1.63
- observed:       1

******e**

- sin22e <0.18
- @2.8x10-3eV2

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## e/ separation @ SK

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## e/ separation @ SK

- sub-GeV
- (Evis<1330MeV)

- multi-GeV
- (Evis>1330MeV)

- An experiment with test beams also confirmed
- PID capability:  PL B374(1996)238

- atm- DATA(1R)
- atm- MC(1R)

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## e/0 separation @ SK

- e/0 separation @ SK

- 70% 0 rejection and
- 30% signal efficiency loss
- for 1R-e sample for K2K

- (rejected as 0 like)

-  MC (1Re)

- signale (m2=2.8e-3)

- (selected)

- (selected)

- M(MeV/c2)

- momentum of the 1st ring (MeV/c)

- 0 induced event

- atm-DATA(1R-e)
- atm-MC(1R-e)
-     (Evis=150-250MeV)

- POLfit

- POLfit

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## NC 0 measurement @ K2K-1KT

- NC 0 measurement @ K2K-1KT

- non-0 BG

**events**

- background
- for e search

- (NC10)/(CCall)=0.064±0.001±0.007 (0.065 by NEUT): Phys.Lett.B619:255,2004

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## SciBooNE (K2K-SciBar detector at FNAL Booster Neutrino Beam line)

- Cross section measurements for T2K
- for both neutrinos and anti-neutrinos
- MiniBooNE near detector
- It will be proposed to FNAL soon
- (cheap/quick experiment)

-          1         2

- E (GeV)

- T2K

- K2K

- SciBar
- at BooNE

- Flux (normalized by area)

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## T2K near detectors

- T2K near detectors

**FGD**

**TPC**

**ECAL**

**UA1**
**Magnet**

**Pi-zero**
**Detector**

**Tracker**

**Lq. Ar TPC**

**Muon**
**Ranger**

**Water**
**Cherenkov**

***The Experimental facility ***
***at 2km is not approved yet***

- ND280:
- Conceptual
- Design
- Report

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## e sensitivity vs. calendar time(possibility of beam power upgrade) 

- e sensitivity vs. calendar time(possibility of beam power upgrade)

- sin2213 sensitivity (90%CL)

- 0.05

- 0.04

- 0.03

- 0.02

- 0.01

- 0

- 10% syst. err assumed
- on BG subtraction

- 400MeV LINAC from FY2011

- 1yr = 130days

- current baseline power

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## Summary

- T2K is approved and the construction is on schedule
- Neutrino experiment will start in 2009
-  13 sensitivity (phase-1):
-     - the latest  MC & SK1 final tools
-     - SK is ideal for separating /e/0, K2K has    demonstrated background rejection in e search
-     - ~10times improvement from CHOOZ
-     - background should be understood < ~10%:
- Seriously considering to increase beam power

- reconstruction @ SK
- 0 production and beam e @ NDs

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## supplement

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## Slide 25

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## Phase 2 ( if 13 can be measured. ) 

- Phase 2 ( if 13 can be measured. )

- 48m × 50m ×500m,
- Total mass = 1 Mton

**2****nd**** Phase (201x~?)**
**Hyper-Kamiokande(~1Mt)**

- nucleon decay search
- CP violation measurement

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## Search for CP violation

**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

**T2K 3******** discovery**

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

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## Signal candidate:

- RUN:      21858
- EVENT:  2240771
- E1:         266.7MeV
- E2:         170.8MeV
- :          22.5 deg.
- M:         83.1MeV/c2

- Looks multi-ring event.

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

## Possibility of beam power upgrade

- Beam Power (kW)

- 0

- 1

- 2

- 3

- Japanese Fiscal Year (Apr-Mar)

- 2008

- 2009

- 2010

- 2011

- 2012

- 400MeV LINAC from FY2011

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005

##   disappearance

 e appearance

beam e

* *e appearance
- beam e

- →-, a→-a for anti.-

- S.Mine(UCI)@PANIC(Santa Fe)

- 30Oct,2005