Status of the T2K long baseline neutrino oscillation experiment

1
Status of the T2K long baseline neutrino
oscillation experiment

• Atsuko K. Ichikawa (Kyoto univeristy)
• For the T2K Collaboration

2
The T2K Experiment

• Physics goals
• Discovery of nm?ne appearance
• Precise meas. of disappearance nm?nx
• Discovery of CP violation (Phase2)

3
T2K Collaboration

• 12 Countries
• Canada, France, Germany, Italy, Japan, Korea,
  Poland, Russia, Spain, Switzerland, UK, USA
• 450 members

4
T2K Layout
Super-K
p
p
m-mon
n
off-axis
2.02.5o
on-axis
120m
0m
280m
2 km
295 km
Dm2atm 2.03.0x10-3eV2 En 0.480.72GeV

• Quasi-monochromatic, sub-GeV Off-Axis Beam
• 2,200 (1,600) nm (CC) interactions at Super-K
  
• 40GeV, OA2.5o, 22.5 kt-yr

5
The Far Detector SK-IV
New Electronics and DAQ installation completed in
08. Super-K is ready.
??ICRR, Univ. of Tokyo
6
SK Typical Event Display
good m-e separation

• Back ground for ne appearance search
• Intrinsic ne component in initial beam
• Merged p0 ring from Neutral Current
  interactions

7
Sensitivity to q13
0.006 at dCP0/p
5?1021 POT
(OA2.5?)
sin22q13 0.1 sin2q23 ½ Dm232 2.5x10-3
BG subtraction 10 error
of events in Enrec0.350.85 GeV
sin22q13 Background in Super-K Background in Super-K Background in Super-K Signal 40 eff Signal BG
sin22q13 nm ne total Signal 40 eff Signal BG
0.1 10 13 23 103 126
0.01 10 13 23 10 33
8
Measurement of q23 , Dm232
DE60MeV
QE

• Use 1R m-like events
• Large QE fraction
• Clear deficit is expected in the reconstructed n
  energy
• dE d(En rec-En true) 60MeV
• ? lt 10 measurement on Dm2

inelastic
En (reconstructed) En (true)
sin22q
1
R(measured / expected)
10-1
Enrec
Dm2
0
1
2
Enrec(GeV)
3
9
Sensitivity nmdisappearance
T2K 5?1021 POT (Stat. only) 5years _at_
full Intensity
Dm2 10-3 eV2
K2K SK
2.9
(OA2.5?)
MC
2.8
Stat. only
2.7
2.6
--68CL --90CL --99CL
2.5

• Goal d(sin22q23)0.01, d(Dm223) lt110-4 eV2

10
J-PARC Accelerators
The Hadron Hall
MR A round1,568m
Materials Life Science Experimental Facility
30 GeV Dec. 08
Apr. 09
3 GeV Oct. 07
Neutrino
3GeV RCS A round348m
181 MeV Jan. 07
Area for Transmutation Experimental Facility
Linac (330m)
Feb.2006
11
The Neutrino Beam-Line
?
?
?
?
?
12
First shot of the proton beam
SSEM (Segmented Secondary Emission Monitor)
On 23rd April 2009
Fluorescent Image
13
Muon Monitor
Dump
Decay Volume
10m
4m
14
(No Transcript)
15
First beam event in Muon monitorand evidence of
neutrino production
Silicon PIN photodiode
15 mV
Scintillator for reference
1 msec
FADC gate
16
Horn focusing
Horn off
Horn on
MUMON Silicon PIN photodiode array
17
Achievement in this April and May

• Nominal intensity 4x1011 p/bunch, 1 bunch/spill
  (0.1 of design intensity)
• Superconducting combined-function magnets are
  working well as expected.
• Beam monitors are working well.
• Intensity monitors, beam position monitors, beam
  profile monitors are working well.
• Beam position at the target is confirmed with the
  fluorescent plate.
• Secondary muons are observed behind the beam
  dump.
• The focusing effect of the electromagnetic horn
  is confirmed.
• Successfully passed the government inspection.

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From Now

• Complete set of 3 horns and installation of ND280
  detectors scheduled for the end of this Fall.
• 100kW commissioning in JFY2009
• Physics run from 2010 ? fist result
• Beyond 100kW 100?750kW(Design)
• Beam loss control
• Linac 400 MeV energy recovery and upgrade of the
  RCS injection system
• Long-term plan toward power frontier (MW)
• KEK roadmap