T2K experiment at J-PARC

T2K experiment at J-PARC

Epiphany 2010 D. Kiełczewska 1

For T2K CollaborationDanuta KiełczewskaWarsaw University& Sołtan Institute for Nuclear Studies

Neutrino oscillations what remains to be measured experimental approach

T2K goals, design & construction Current status

Epiphany 2010, Kraków

What we know and don’t know about neutrino masses

D. Kiełczewska

log m2

νe νμ ντ

10-2 eV

10-1 eV

1 eVlog m

Epiphany 2010

Δm223 <0Δm2

23 >0

2

|Δm223|=2.4 x 10-3 eV2

Δm212 = 7.6 x 10-5

eV2

40 meV < mii=1

3

∑ < 2 eV

What is the hierarchy?

What do we know about mixing?

1 2 1 2

1 2 1 2 3 2 3

2 3

1 3 1 3

1 1

2

2 3 3 3

0

0 1 0

0

0

0

0

1 0 0

0 0

0 0

1 0 0

00 1

0

i

i

i i

c s e

s e c

c s

s c

c s

cU s e

e

cos

sini j i j

i j i j

c

s

2 o o23sin 2 1.02 0.04 (37 -53 ) - is it maximal? which octant?

sin2 212 =0.86 +0.03 (12 =34o)2 o

13 13sin 2 0.14 at 90% c.l. ( 10 )

We need to measure: <- more precisely

solar atmospheric 0νββ

D. Kiełczewska

23

13

Epiphany 2010 3

Global analysisGlobal

analysis

on the basis of the data at Nu2008T. Schwetz et al. arXiv:0808.2016

213sin 2 0.04 <0.15

D. KiełczewskaEpiphany 20104

SNO: arXiv:0910.2984

sin213 =0.020−0.016+0.021

sin213 < 0.057 (95% c.l)

What is expected ?

63 models, arXiv:hep-ph/0608137

We would better measure it!

D. KiełczewskaEpiphany 2010

5

How to measure

sin213 < 0.04

We need:

an experiment with L/E corresponding to

transition to/from good precision (a few %)

2atmm

or e eν ν

eμν ν

13

Reactor e eν ν disappearance

Accelerator appearance

Pvac (νμ → νe) =sin2 213 ⋅sin2 23 ⋅sin

2 1.27m132 ⋅L

E

+ f (CP ,sgn(m132 ))

D. Kiełczewska

Δm2atm

Δm2solar

P(νe→ νe) ≈1−sin2 213 ⋅sin

2 1.27m132 ⋅L

E

13

13

mass hierarchy

CP violation

νe νμ ντ

Epiphany 20106

D. KiełczewskaEpiphany 2010 7

Accelerator experiments of second generation

• Powerful neutrino sources • „off axis” beams

T2K Novasite Japan USAbeam since 1/04/2009 NuMi (upgraded)Eν (peak) 0.76 GeV 2.22 GeVdistance 295 km 812 kmFar detector Super-Kamiokande to be builtof mass (FV) 22.5 ktons 14 ktonsStatus Starts taking data Excavations started

D. Kiełczewska

Owing to higher energy and larger distance, NOvA will be more sensitive to matter effects (mass hierarchy).

Combining the NOvA and T2K results will facilitate the separation of CP from matter effects.

Epiphany 20108

T2K experiment(Tokai to Kamioka)


T2K Collaboration


SINS WarsawNINP KrakowWarsaw Technical U

508

T2K Off Axis BeamQuasi monochromatic beam

295 km

Neutrino energy

2 2

0.43

1

EE ν

Kinematics of decay

D. Kiełczewska

Tunable neutrino energy to oscillataion maximum Reduced tail at high ν energies helps to reduce background due to production

Epiphany 2010

0

11

J-PARC accelerator laboratory in Tokai


Upstream of Linac Tunnel

NeutrinoTunnel

50 GeV Tunnel

From 3 GeV toMaterials and Life

Middle of Linac Tunnel

From Linacto 3 GeV

3 GeVExtraction Point

TunnelTour

JPARCJPARC



Near detector ND280

(including all 3 horns)

Beam commissioning

(Apr- May 2009)


Protons extracted from MR with superconducting magnets.

Proton beam tuned within 3mm to the designed orbit

Muon monitor


Array of Si photodiodesand ionization chambers

Focusing effect of a horn with 273 kA

For precision measurements


We need:

precise beam determination in particular we need to know Far/Near ratio with an accuracy of 2-3%NA61 /SHINE experiment

talk by Magda Posiadała

cross –section measurements νe component in the νμ beam

near detectors

Near Detector ND280


ND280 off-axis detector


UA1 magnet 0.2 Tinner volume 3.5x3.6x7 m3

P0D – optimized for NC π0 production scintil. bars covered with lead & water layers

ECAL – elmgt calorimet. SMRD – muon ranger SMRD talk

by M. ZiembickiSMRD talkby M. Ziembicki

Tracker - optimized for neutrino spectrum

determination FGD (to select CCQE events) (scintil bars and water layers TPC (e/μ sepeartion and momentum measurement)

SMRD counters in magnet slits

Installation of magnet and SMRD(2008-2009)


ND280 components (now installed)


To test the performance of the TPC, electrons, pions, muons, and protons were used in TRIUMF (momenta up to 400 MeV/c).

INGRID

TPC FGD

First neutrino event in ND280


INGRID – on axis detectorto determine beam’s direction and profile

Consists of 14 modules (16 planned)

Every module (1x1x1 m3) composed of 11 alternating planes of plastic scintillators (5x1x100 cm3)and iron plates (6.5 cm thick)

Far detector: Super-

Kamiokande IV


50 kt of water, about 13 000 PMTsDetector well tested during over 10 years of data taking

All front-end electronics and on-line systems renovated

- ready for T2K.

GPS based system selects events correlated with T2K beam spills

μ

e

π0

Super-K allows to identify with good efficiency electrons, muons and low-energy π0

D. Kiełczewska

The signal searched for in Super-K:

Background mainly from:

νμN → νμN 0

νμ → νμ

eμν ν

Also from νe

beam admixture- around 0.4% νμ

Epiphany 2010 24

Neutrino energy reconstruction in SK


Protons below Cherenkov threshold

One ring events

Muons/electrons well identified and reconstructed

Expected νe appearance signal


after 5 years at full intensity (750 kW) – 8x1021 pot at 30 GeV

Sensitivity to ϑ13


5 years

Sensitivity to ϑ23

and Δm223

νμ disappearance


Minos 3.36x1020 pot

Stat. only

T2K goal:

m232

( ) : 1×10−4eV2

sin2 2 23( ) : 0.01

K2K – PRD74, 072003 (2006)SK – PRL 93, 101801 (2004)MINOS – PRL 101,13180 (2008)

--90%CL--99%CL

(OA2.5)(OA2.5)

stat. only

Summary


T2K – the first oscillation experiment of the 2nd generation has just started

Primary goals: determination of ϑ13

better precision of ϑ12 and Δm223

First beam commissioning has been successful Most of ND280 components installed and commissioned first neutrino interactions recorded in INGRID

Super-K ready and waiting for beam events Physics data taking starts > Jan. 20, 2010

essential for CPV studies in lepton sector

stay tuned

Documents

T2K experiment at J-PARC