Status of T2K
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Transcript of Status of T2K
Status of T2KTakashi Kobayashi
KEKFor T2K collaboration
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June 14, 2010Neutrino 2010@Athens, Greece
The T2K Collaboration
CanadaTRIUMFU. AlbertaU. B. ColumbiaU. ReginaU. TorontoU. VictoriaYork U.
FranceCEA SaclayIPN LyonLLR E. Poly.LPNHE Paris
GermanyU. Aachen
~500 members, 61 Institutes, 12 countriesItalyINFN, U. RomaINFN, U. NapoliINFN, U. PadovaINFN, U. Bari
JapanICRR KamiokaICRR RCCNKEKKobe U.Kyoto U.Miyagi U. Edu.Osaka City U.U. Tokyo
PolandA. Soltan, WarsawH.Niewodniczanski,
CracowT. U. WarsawU. Silesia, KatowiceU. WarsawU. Wroclaw
RussiaINR
S. KoreaN. U. ChonnamU. DongshinU. SejongN. U. SeoulU. Sungkyunkwan
STFC/RALSTFC/Daresbury
USABoston U.B.N.L.Colorado S. U.Duke U.Louisiana S. U.Stony Brook U.U. C. IrvineU. ColoradoU. PittsburghU. RochesterU. Washington
SpainIFIC, ValenciaIFAE (Barcelona)
SwitzerlandU. BernU. GenevaETH Zurich
United KingdomImperial C. LondonQueen Mary U. L.Lancaster U.Liverpool U.Oxford U.Sheffield U.Warwick U.
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T2K (Tokai to Kamioka) experiment
High intensity nm beam from J-PARC MR to Super-Kamiokande @ 295km
Discovery of ne appearance Determine q13 Last unknown mixing angle Open possibility to explore CPV in lepton sector
Precise meas. of nm disappearance q23, Dm232
Really maximum mixing? Any symmetry? Anytihng unexpected?
132312sin ssse nn m prob. in term odd CP sinq12~0.5, sinq23~0.7, sinq13<0.2)
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Remarkable Features of T2K High intensity neutrino beam from J-PARC
First “Super beam” experiment w/ O(MW) beam Narrow spectrum tuned at the oscillation maximum.
First application of “Off-axis beam” (cf. BNL-E889 proposal)
Less background, High sensitivity World largest water Cherenkov detector SuperKamiokande
High efficiency for low energy Good PID (e/m) capability
Neutrino energy reconstruction by using Quasi-elastic (QE) interaction (nl+n l- + p) s~80MeV Oscillation pattern measurement BG due to miss-reconstruction of inelastic interaction
Greatly improved by using narrow spectrum
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>10times improvement3.75MWx107s
Expected Sensitivity of T2K
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Goal @ 3.75MWx107s: (sin22q23)~0.01,(Dm2
23) <1×10-4 [eV2]
nmne appearance nm disappearance
CP=0
MINOS, PRL 101, 131802 (2008)
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2.5 deg Off-axis Peak ~600MeV Quasi-Elastic interaction dominate
Less Non-QE background Muon monitors @ ~120m
Muon > 5GeV Spill-by-spill monitoring of
direction/intensity Near detector @280m
On-axis detector “INGRID” Intensity and direction (profile)
Off-axis (toward SK direction) Absolute flux/spectrum/ne
Far detector Super-Kamiokande @ 295km
Experimental Setupp p n
120m0m 280m 295 km
on-axisoff-axis
2.5o
m-mon
n m fl
ux (a
rb. u
nit)
Near detectors
Super-Kamiokande
MC (GFULUKA)
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J-PARC Facility(KEK/JAEA )
Bird’s eye photo in January of 2008
South to North
Neutrino Beams (to Kamioka)
JFY2009 Beams
Main ring
JFY2008 Beams
3 GeV Synchrotron
CY2007 Beams
Linac
Design Intensity750kW
ConstructionJFY2001~2008
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Neutrino facility for T2K at J-PARCTarget
Primary beamline (superconducting)
Electromagnetic hornNeutrino monitor bld.
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Muon monitors
Fast Extracted (FX) beam from MR (30GeV) 6bunches (8 from Fall 2010) 581ns apart
Proton beam transport Superconducting combined function magnets
Graphite target (26mmfx90cm) 3 horns @ 320kA (250kA by summer) 110m of decay volume SK direction is given by GPS survey at 2mrad precision
Construction (JFY2004~2008) COMPLETED as scheduled!
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2 Near Detectors
Scintillator tracker & Iron sandwich
UA1 magnet(Donated From CERN)
INGRID & off-axis completed in 2009 (Except side ECAL) Side ECAL installation in Summer 2010
Commissioning completed
SMRDIn magnet yoke
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Far Detector: SK-IV
ICRR, Univ. of Tokyo
50kt Water Cherenkov detector operational since 1996 11129 20" PMTs in inner detector (ID), 1885 8" PMTs in outer
detector (OD) Readout electronics has been renewed in 2008 summer.
dead time less DAQ system SK is working very stably Beam related events are selected by event timing using GPS
system.
Milestones 1999: Nishikawa&Totsuka proposed to measure ne
appearance as a next critical step toward CP measurement 2001: “The JHF-Kamioka Neutrino Project” report
(hep-ex/0106019) April 2004:
Officially approved by Japanese Government and 5yr Construction started
T2K international collaboration officially formed March 2009: Construction completed as scheduled April 23, 2009: First neutrino beam production and
commissioning started January 2010: Data accumulation for oscillation search
started! Feb. 24, 2010: First T2K Event in Super-Kamiokande! 11
Beam commissioning
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Target size
Horizontal: 1mm
Vertical: 2mm
Beam orbit is tuned within 2mm from design orbit.(Critical for controlling beam loss)
SSEM inSSEM out
SSEM foil: 5x10-5 loss→ real loss << 0.5W @50kW
No significant beam loss w/o SSEM
Beam loss along proton beam line
OTR detector just in front of target worked very well!
OTR beamPotision meas.Linearity
Beam commissioning
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MUON MONITOR MEASUREMENTS
Horn focusing effect clearly seenAlighment &Targeting check
Beam wid. ~4mm(1s)
Target size Functionality of all components confirmed Beam commissioning COMPLETED
Linear upto 70kW within 1%
Started data taking for oscillation!
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70kW
50kW
Delivered # of protons: 2.34×1019 (Jan-May) Continuous run @ ~50kW level Trial upto 100kW done
(2010)
Proton beam stability Beam position on target have to be controlled < 1mm
To control direction of secondary beam within 1mrad To avoid destroying the target from non uniform thermal
stress on target (at higher power) Succeeded to control <1mm during long term operationCorrelation btw p beam positionon target vs MUMON center
1mrad
~3mm
Horn lens effectRMS 0.4mm
RMS 0.4mmCurrent
B
B
p beam
p+
p+
Beam direction & intensity stabilitymeasured by Muon monitor
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Beam direction is controlled well within 1mrad Secondary beam intensity (normalized by proton intensity) stable within 1%
(reflects stability of targeting, horn focusing, etc) Stable well within our physics requirements
Jan Feb Mar
Detector intrinsic resolution <1.5mm
Apr May
0
-10
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Profi
le c
ente
r (c
m)
Mu(
Si)
Tota
l Q/Np
Jan Feb Mar Apr May
RMS/MEAN < 1% (whole period)
INGRID measurements
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Bunch structure clearly seen as expected Event rate is stable for wide range of intensity Beam direction well controlled within requirement (<1mrad)
Off-axis detector performances
Very small number of bad channels
Hit Efficiencies >99%For all layers (FGD)
32 0.4%
s~8%(400~500MeV/c)
dE/dx from TPC
Off-axis detector n measurements
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Event rate are stable
FGD cluster timing
FGD
ECAL
P0D
Super-Kamiokande Event Selection J-PARC neutrino events selected by event timing using GPS SK analysis is very well established
>20yrs of experiences w/ Water Cherenkov detector Event selection & cut values are fixed already
UNBIASED SELECTON Selection criteria
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For nm disappearance analysis For ne appearance search
Timing coincidence w/ beam timing (+TOF)
Fully contained (No OD activity)
Vertex in fiducial volume (Vertex >2m from wall)
Evis > 30MeV Evis > 100MeV
# of ring =1
m-like ring e-like ring
No decay electron
Inv. mass w/ forced-found 2nd ring < 105MeV
Enrec < 1250MeV
Observed SK events
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Event time distribution clearly show beam structure Observed # of Fully contained events: 22 (by Mid. May) Expected non-beam BG: <10-2evts
FCODLE
FC
LE: Low energy triggered eventsOD: Outer detector eventsFC: Fully contained events
SK events
Single-ring m-like event Two-ring event
Pink diamonds are placed on the wall in the beam direction starting from the reconstructed vertex.
Analysis Strategy Predict SK observations (nm,ne): Nm/e(En
rec,Posc) BASED ON T2K&NA61 measurements as precisely as necessary
Then compare w/ SK observation
Intensive analysis of beam, near detector, NA61 and SK are on going 23
NDNFSK R /
truerectruetruetruetrueexprec , nnnnnnn s EEfEEEPEEN SKSKoscSK (omitting integral of En
true)
Flux at SK Osc. Prob. Cross sect. Det. Eff. SK Det. Responce
Enrec: Reconstructed neutrino energy
Entrue: True neutrino energy
DNNDNDND N s obs
Far-to-near extrapolation factor
SK flux Flux at ND
Normalization & Spectrum from ND measurements
Hadron production measurement NA61
Hadron production measurement CERN NA61
Pilot run in 2007 and high statistics data in 2009 p (30GeV) + C (thin target 4% λI and T2K replica
target ) Preliminary results on p production from 2007
thin target data were released. They are being implemented in T2K beam MC.
Preliminary NA61 π+, 20% syst. error
Prelim
inary
MC=GFLUKA
Future plan Until end of June, 2010
~50kW Jul – Fall, 2010 (Summer shutdown)
New Kicker magnets and power supply installation (68bunch)
Horn power supply replacement (Old K2K New!) Remaining ECAL installation
After Nov. 2010 From ~100kW toward design power
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Summary Construction completed Mar.2009 as scheduled First beam on Apr.23, 2009 Data accumulation for oscillation search started in Jan. 2010
Continuous operation at ~50kW level Accumulated 2.34E19 protons (Until June 1st, 2010) Observed # of FC events: 22 (by Mid May)
After Summer: from ~100kW toward design power Intensive analysis going on to extract physics! Goal
Accumulate 0.75MW x 5x107sec (=3.75MWx107sec) Discover ne appearance
sin22q13 down to 0.018 (3s), 0.008 (90%CL) Precise measurement of nm disappearance
(Dm232)~1x10-4eV2, (sin22q23)~1%
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Posters on T2K1. Masashi Otani (Kyoto U.), “The Result from the T2K Neutrino Beam Monitor
INGRID”2. Suzuki Kento (Kyoto U.), “T2K Beam Study with the Muon Monitor”3. Tatsuya Kikawa (Kyoto U), “Development of the new T2K on-axis neutrino
detector INGRID proton module”4. Gavin Davies (Lancaster U.), “Understanding and Calibrating the Calorimeter
for the T2K Near Detector”5. Takatomi Yano (Kobe U.), “The Side Muon Range Detector for the T2K
experiment”6. Masahiro Shibata (KEK), “Commissioning of the neutrino beam facility for the
first superbeam experiment T2K”7. Georgios Christodoulou (U. of Liverpool), “T2K : Electron Neutrino Analysis
at the Near Detector (ND280)”8. Luigi Esposito (ETHZ), “NA61 data for T2K flux calculations”9. Tomasz Palczewski, “Particle production cross-sections by 30GeV protons ”10. Jeremy Maxime Argyriades (Geneva) “SHINE-NA61 experiment and
applications for neutrino fluxes”27