T2K experiment at J-PARC Epiphany 2010D. Kiełczewska1 For T2K Collaboration Danuta Kiełczewska Warsaw 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 m 2 νeνe   eV eV 1 eV log m Epiphany 2010 Δm 2 23 <0Δm 2 23 >0 2 |Δm 2 23 |=2.4 x eV 2 Δm 2 12 = 7.6 x eV 2 What is the hierarchy?

What do we know about mixing? - is it maximal? which octant? We need to measure: <- more precisely solar atmospheric 0νββ D. Kiełczewska Epiphany

Global analysis on the basis of the data at Nu2008 T. Schwetz et al. arXiv: <0.15 D. Kiełczewska Epiphany SNO: arXiv: What is expected ?

63 models, arXiv:hep-ph/ We would better measure it! D. Kiełczewska Epiphany

How to measure We need:  an experiment with L/E corresponding to  transition to/from  good precision (a few %)  Reactordisappearance  Accelerator appearance D. Kiełczewska Δm 2 atm Δm 2 solar mass hierarchy CP violation νeνe   Epiphany

D. Kiełczewska Epiphany 20107

Accelerator experiments of second generation Powerful neutrino sources „off axis” beams T2K Nova site Japan USA beam since 1/04/2009 NuMi (upgraded) E ν (peak) 0.76 GeV 2.22 GeV distance 295 km 812 km Far detector Super-Kamiokande to be built of mass (FV) 22.5 ktons 14 ktons Status 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

T2K experiment (Tokai to Kamioka) Epiphany 2010D. Kiełczewska9

T2K Collaboration Epiphany 2010D. Kiełczewska10 SINS Warsaw NINP Krakow Warsaw Technical U 508

T2K Off Axis Beam Quasi monochromatic beam 295 km Neutrino energy Kinematics of  decay D. Kiełczewska  Tunable neutrino energy to oscillataion maximum  Reduced tail at high  energies helps to reduce background due to production Epiphany

J-PARC accelerator laboratory in Tokai Epiphany 2010D. Kiełczewska12

Upstream of Linac Tunnel Neutrino Tunnel 50 GeV Tunnel From 3 GeV to Materials and Life Middle of Linac Tunnel From Linac to 3 GeV 3 GeV Extraction Point Tunnel Tour JPARC D. Kiełczewska Epiphany

D. Kiełczewska Epiphany Near detector ND280 (including all 3 horns)

Beam commissioning (Apr- May 2009) Epiphany 2010D. Kiełczewska15 Protons extracted from MR with superconducting magnets. Proton beam tuned within 3mm to the designed orbit

Muon monitor Epiphany 2010D. Kiełczewska16 Array of Si photodiodes and ionization chambers Focusing effect of a horn with 273 kA

For precision measurements Epiphany 2010D. Kiełczewska17 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  ν e component in the ν μ beam near detectors

Near Detector ND280 Epiphany 2010D. Kiełczewska18

ND280 off-axis detector Epiphany 2010D. Kiełczewska19  UA1 magnet 0.2 T inner volume 3.5x3.6x7 m 3  P0D – optimized for NC π 0 production scintil. bars covered with lead & water layers  ECAL – elmgt calorimet.  SMRD – muon ranger SMRD talk by M. Ziembicki SMRD talk by 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 ( ) Epiphany 2010D. Kiełczewska20

ND280 components (now installed) Epiphany 2010D. Kiełczewska21 To test the performance of the TPC, electrons, pions, muons, and protons were used in TRIUMF (momenta up to 400 MeV/c). INGRID TPCFGD

First neutrino event in ND280 D. KiełczewskaEpiphany INGRID – on axis detector to determine beam’s direction and profile Consists of 14 modules (16 planned) Every module (1x1x1 m 3 ) composed of 11 alternating planes of plastic scintillators (5x1x100 cm 3 ) and iron plates (6.5 cm thick)

Far detector: Super- Kamiokande IV Epiphany 2010D. Kiełczewska23  50 kt of water, about PMTs  Detector 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

 e π0π0 Super-K allows to identify with good efficiency electrons, muons and low- energy π 0 D. Kiełczewska The signal searched for in Super-K: Background mainly from: Also from ν e beam admixture - around 0.4% ν μ Epiphany

Neutrino energy reconstruction in SK Epiphany 2010D. Kiełczewska25  Protons below Cherenkov threshold  One ring events  Muons/electrons well identified and reconstructed

Expected ν e appearance signal Epiphany 2010D. Kiełczewska26 after 5 years at full intensity (750 kW) – 8x10 21 pot at 30 GeV

Sensitivity to ϑ 13 Epiphany 2010D. Kiełczewska27 5 years

Sensitivity to ϑ 23 and Δ m 2 23   disappearance D. KiełczewskaEpiphany Minos 3.36x10 20 pot Stat. only K2K – PRD74, (2006) SK – PRL 93, (2004) MINOS – PRL 101,13180 (2008) --90%CL --99%CL (OA2.5) stat. only

Summary Epiphany 2010D. Kiełczewska29  T2K – the first oscillation experiment of the 2nd generation has just started  Primary goals:  determination of ϑ 13  better precision of ϑ 12 and Δ m 2 23  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